Welcome to the BugShop FAQ

The text following is part of a series of articles written by John S. Henry on the restoration and maintenance of air-cooled Volkswagens. While his experience is exclusively with the Beetle, many of the techniques can be applied to other models.

This text is copyrighted and duplication, re-distribution or publication is prohibited without consent of the author.

Article: The DIY Paint Job
Last updated:12/9/01

The DIY* Paint Job
(* "Do it yourself")

{Note, click on any of the thumbnailed pictures in this article for a full sized image in another browser window}

Symptom: You want to paint your own car; you want to know what it takes to paint your own car; you need to be talked out of trying to paint your own car.


“I want to paint my own car, can you tell me what's involved?”

“Why can't I paint my own car?”

“How hard is it?”

“How much does it cost?”

“What is the best kind of paint to use?”

“Can I paint in my garage, or should I do it outside?”

These are all questions that I have either received in e-mails or seen float past on the newsgroups.  And while I am no bodyshop expert, I have dabbled in enough of auto painting that I feel like I can offer some useful info.  My goal is to try and break down at least some of the "mystery" of auto painting.  What goes on behind those expensive, closed doors at that autobody shop?

First of all, like many of my articles some pre-preaching.  I firmly believe that there are only two ways to paint a car.  One is to do it the right way, to use all the right materials, methods, tools and techniques.  The other way is just cover the car with a substance that makes it a different (or same) color and do that as cheaply as possible.  There is no in-between.  And yes, the latter of the two methods is probably cans of Krylon spray paint, or whatever brand is on sale.

Why do I believe this?  Because anything less than the "right way" (proper materials, tools, techniques, etc.), isn't going to last all that much (if at all) longer than the "Krylon" method.  Perhaps that isn't true in every case, but if you can paint a car with a rattle can for $30, or you spend $150 for some off brand auto paint and a borrow a compressor and spray gun, and use no primer, and get oil and water in the air you use to spray it, and don't mask off what you should; it isn't going to be 5 times better than the $30 Krylon job.  You either do it all right, or just go the cheap route.

And I'm not undermining the spray paint job.  It may meet your needs, you may read this article and take away many techniques that you could use with the department store rattle cans.  I really think with enough preparation, the Krylon job could be done to look halfway decent.  Certainly isn't going to last long, but it might look ok.  But if you go any further, you must go all the way in my opinion.  Spending good dough on auto paint, but not doing the right prep, or using the right gun, or not taking off parts you should, is a travesty in my book.

And while this article will find its primary home at my own VW Beetle Restoration website “The BugShop”, there is really no Beetle, or even VW specific stuff in here.  For more Beetle particulars, as well as other important info on painting, I encourage you to explore my website, in particular the last two articles on “Doing a #4 Resto”.

But to start here,  let me give you some background.  My “Painting Resume” if you will.

1982 or thereabouts; I scraped away all the yellow latex house paint from my first car, a ’68 Beetle, rented the Charleston Air Force Base Auto Hobby shop paint booth for a day, and sprayed a gallon of “Rally Yellow” DuPont Enamel on top of department store rattle can primer.  Result:  From a distance OK, lots of “Orange Peel”, some flaking and peeling of only a year or two later.
1984-ish; paid an old  high school acquaintance $50 to paint the ’68 again, a slightly “dimmer” shade of yellow (I had to buy the paint).  Sprayed over sanded yellow paint from the previous job, some department store primer and various other stuff.  Result: much better than my previous effort, lasted about the same.  A pretty dull finish overall.
1987; over auto parts store rattle can primer, paid a shady shop worker $700 to shoot a Corvette White enamel on my ’67.  Result:  Pretty nice, a couple runs he fess’ed up to.  Paint weathered OK, but flaked and peeled in a few places.  Lost it's shine pretty quick.  And that bra was a big mistake, ruined the paint underneath within a year.
1999; paid a friend who owned a body shop somewhere around $4100 to paint my prized ’57 Beetle.  This after I had the entire body sandblasted, and he spent many hours “skimming” shallow dented panels to produce a show car finish.  Shot with all Spies-Hecker 2 stage acrylic urethanes (series 293).  Result: It looked like a $5000 paint job, the finish was like a mirror and to date has held up very well and looks as good as the day it was new.
2000; painted my own ’85 VW Cabriolet in my own garage with Spies-Hecker urethanes (primer, base and clear coat, same paint as was used on my ’57).  Spent about $400 for paint and related materials. Result: other than the hood that I hurried the prep work on, it really looks pretty decent.

For what it is worth, only the last two efforts above are the right way.  In hindsight, the first three might just have well been cans of Rustoleum, and I would have had a lot of money left over to buy other neat VW stuff.  But "can I do it the 'right' way myself?".  Sure you can.  If you invest the $$ in the proper tools and materials, invest the time to learn the techniques, have access to or own the proper environment AND set your expectations accordingly, you can do it.  This article is about how I "did it myself".

I bought my '85 VW Cabriolet in 1993, it had 96,000 miles on it.  Over 7 years, I did all of the maintenance, put a new top on it, made a few mods along the way, and basically loved driving it.  But in 2000, with 225,000 miles on it, the body was looking pretty tired.  New England winters were taking their toll on the body (as had an old lady in Ford Explorer at my church, numerous shopping carts and bikes, an as-yet-unidentified vehicle and, yes, me).   And in one bizarre incident, after replacing the reverse light switch (left the car in reverse) and an emergency brake cable (left the emergency brake off), I reached in through the open passenger window and started the car..... and proceeded to watch it back all the way through the closed garage door behind it.  The car needed help, one more salty winter and the body was going to be beyond help.  Bubbly "cancers" were starting to show on the doors.  The lower corners were getting the traditionally brown-orange rust color.  I had to do something...

I resolved that due to my financial situation, I could not afford to drop the car off at Tom's shop again and contribute another $2500-$3500 towards his retirement.  Of course if I did, it would look great, but the first time I passed the salt truck this winter, I would hate myself.  So resolved to take what I had learned doing my Beetle and hanging around Tom's shop, reserve a long weekend and paint the car myself in my garage.  I would do the best job I could, and be happy with the results, whatever they were.  This was critical.  "I will be happy with the results, whatever they are." "I will be happy with the results, whatever they are." "I will be happy with the results, whatever they are." "I will be happy ...................

So let's get started.  This article will discuss different areas of materials, tools and techniques, then will go into the specific steps I used.  The fact that my car was a water-cooled VW is pretty irrelevant here I think, the techniques could be applied to any vehicle.  Just below is a hot index if you want to jump to a specific section.

About the Paint
What to take off the car
Tools- Compressor
Tools- Compressor Lines
Tools- Spray Guns
Mask (and other safety considerations)
The Spray Environment
The Steps
The verdict (what I would have done differently)
Other resources

About the Paint

Believe me, I am just a cheap as the anyone.  If I'm going to pay $80 for a quart of paint, I better know what it does, why it is so expensive and what my alternatives are (competitors selling for less?).  Real auto paint is expensive, that is just a fact a of life.  Get ready for some serious sticker shock when you go to the autobody supplier.  Automotive finishes are a science, that is, "measurements of polyurethane microgel deposition and clearcoats with the oscillation technique to determine the viscosity-temperature behavior correlate well with technical properties of the final films".  Huh?  Well, I am not an expert, but here is some of what I have learned:

In the beginning there were lacquers, they usually needed to be rubbed, polished, and waxed to have a good luster and shine.  Then came Synthetic Enamels.  They had a resin base as opposed to a nitrocellulose one.  This resin benefited from heat-accelerated drying, or it would remain soft for a long time.  It needed no polishing.  Acrylic lacquers came next, which used an acrylic resin as a base and a plasticizer to keep the the paint from becoming too brittle.  Acrylic lacquers were used extensively by General Motors in the 50s and 60s. Acrylic enamel came next, it is modified with acrylic resin and is insoluble in solvent when cured, unlike lacquers.   In roughly the mid 70s., polyurethanes emerged.  Their durability over the enamels and lacquers (they are much more "flexible") made them desirable.  The technologies were further refined in the development of acrylic urethane single stages, and base / clear finishes which are the most durable paints available today.  Modern paint additives for curing and hardening further improve the paint's performance.

But by far, the most important thing when choosing a paint is this: you must use a paint system when you paint your car.   That is all of the material, primers, sealers, surfacers, base coats, clear coats, reducers, thinners, hardeners, etc. must all be of the same manufacturer and compatible with each other.  This is why you need to consult with a paint supplier as to what is right is right for your car.  This is why you can't primer your car with Autozone's sandable auto primer (on sale for $1.99 a can!!) and spray it next year with God-know-what brand auto paint you haven't decided upon yet.

How much will the paint cost?  Material budget for single stage should amount to $250 - $400, depending on color and size of the car. Now this includes primers, reducers, paint catalysts (if needed) and materials like paper, tape, sand paper, sanding/grinding discs and filler.  Yes, you will use filler, no matter how perfect your car is.  Add an additional $75-$100 or so for clear coat. Always read the label directions for mixing, application, and safety.   Better yet, get your hands on the manufacturers handbook for the paint line.  Most all decent paint manufacturers have a book that specifies the mix volumes, "pot" life, drying time, etc. for each product (paints, primers and undercoatings) in the line.  Many traditional paints such as acrylic enamels and lacquers are still available, but most agree that urethanes are the superior paints today. They are relatively easy to shoot and are very durable.  They are also more expensive and typically have more dangerous vapors.

How much paint will you need?  I used a single quart of unreduced paint for my '85 Cabrio.  That quart alone was about $80.  Now keep in mind a few things that affect, either positively or negatively, the paint usage.  One, my car was a convertible (no painted roof), two, I used a gravity feed HVLP gun, three I had literally no practical experience painting cars and four, I really only sprayed one heavy color coat.  You may also find, depending on where you buy your paint, that you may be forced to buy much more stuff than you need.  For example my supplier could only supply primer in a gallon can, and the filler as well.  Some suppliers can mix paint in any quantity you want however, my friend Tom mixes paint right at his shop, but then again he usually only mixes smaller quantities for collision repair jobs. And remember that there is no way to fix a paint job that does not have adequate coverage except for repainting the entire car.  That said, I still dropped $400 for paint and materials for my small 'vert, but I have a bunch of primer and a bunch of filler leftover.

Another lesson learned, do not store your paints and supplies in garages that drop below freezing.  Some paints will be unusable after they have been frozen.

What to take off the car

The simple rule is the more you can take off the better.  Many times it is far easier to remove something than to try to mask it off correctly.  Bumpers, lights, door handles, body moldings, antennas, grilles and mirrors.  If you are at all familiar with how you car is put together, this should be relatively easy.  Removing windows is preferred, but not necessary.   Allow at least a full 1/2 day for this.  Take your time and mark anything that could be confusing to put back on.

The real mark of a cheesy paint job is overspray on moldings or mask marks on something that could have been removed with a single screw.

Here's a pic of my '85 cabrio just as I was starting the "weekend paint" job.  Note that the moldings have been removed and you can see a couple areas where rust in the early stages was being addressed.  The forward part of the front wheel arch had some perforation and there was a big old crease dent in the extreme end of the rear quarter, upper, that I had my body shop owner friend pull out with the Eagle.

But back to the windows for a minute, here's a great trick for painting around them: fixed windows like the front and rears, usually have a seal with an extended lip that sticks out over the body a bit.  Sure you could mask that off real precisely at the rubbers edge, but you will still see a masking line there when it is all said and done.  A common trick shops use involves using a 1/8" -3/6" (3mm-4mm) diameter cord, like a nylon sheathed close line.  Pull the rubber lip back and go along shoving the cord under the lip with a popsicle stick, all the way around.  Cut the cord at the end so the ends just touch under the seal.  Shove it under the seal just enough so that when you let go of the lip, its outermost edge is being held up off the surface of the body by about the diameter of the cord.  If you shove the cord back in too far, and the lip will roll over and down "swallowing" the cord.  You don't want that.  Now mask off the rubber seal, rolling the tape just around and under the suspended lip edge a tiny bit.  You should be able to see the cord all the way around.

Now when you spray, the body surface normally covered by the lip will be exposed a bit, allowing paint to "mist" up under there, well beyond where the edge of the rubber lip normally lies.  When the paint is dry and the tape and cord is removed, the lip will lay over newly painted surface and your car won't have that "amateur" paint job look to it.  (Sorry I don't have a picture of this technique... I'll try to get one later)


Ok, this is only distantly related to paint, but worth mentioning.  Stripping is about removing existing paint and coatings from your car before you paint.  Remember, no matter what kind of paint you shoot on an already painted car, it will only be as good as the paint products under it.  My rule of thumb is that unless the car is covered in known original paint, in pretty good shape, I would strip it to bare metal.  You really don't want to waste your money and hard work on a $300 Earl Sheib paint job underneath it all, do you?

There are 3 basic ways to strip paint:

  • Mechanical, abrasive stripping (grinders, DA sanders, wire wheels, ScotchBrite pads, etc.)
  • Chemical (liquid) Strippers
  • Abrasive Blasting
For any large area stripping, and for many other things, I am a huge fan of abrasive blasting.  More on that below.

There are many good mechanical stripping tools/products, but what every professional body shop I have seen uses to strip paint is the good old "DA" sander and 80 grit paper.  If you have a good air supply and a good DA (and 8" one will do a lot of work very fast) this is the way to go.  Still not as fast as abrasive blasting and hard, if not impossible to get into tight corners and irregular areas however.

I have only used chemical strippers once, it was enough to convince me that I didn't want to use them again.  A huge environmental, messy disaster.  It is all too easy to get liquids down into areas that you cannot see, rinse, reach or paint, and then after the paint is shot, you see the effects of that.  I know there are many folks who swear by them, and no doubt some who can use them effectively.  But I'm not one of them, we'll leave it at that.

Abrasive stripping is by far the fastest and most effective way to remove old coatings.  Now you may have heard that abrasive blasting heats and warps metal, and that you will "find" sand in your car for years to come.  Well, in my experience, neither has been true.  Taking your work to a competent shop will insure this.  I had my '57 Beetle media blasted, inside and out, top and bottom.  The shop ("Prep Rite" in Tewksbury, MA) uses a fine aluminum oxide media, blasts it at 25 psi and 300cfm (yes, no typo, 300 cubic feet per minute).  There is no heat build up and no warping.  About 20 minutes with my own shop vac and crevice tool on it with my '57, and it was the last I saw of the blasting abrasive in that car.  A good shop knows how to plug orifices with tape to keep from filling them.

Can you sandblast yourself?  Sure you can.  All you need is about a 30 cfm air compressor and blasting gun.  You need a huge, expensive compressor.  If you have that and are willing to invest in a blasting gun, it may be for you.  If you are like me with a 3.5 hp compressor, your uses for sandblasting will only be stripping small parts or small panel areas.  I have one of those "blast out of a bucket" rigs that you can get at Sears for about $20.  They actually work very well.  That is if you can get the proper abrasive.  I am fortunate in that a hardware store near me sells "Black Beauty" (silicon carbide, black sand) in 100 lb bags for $9 a pop.  In 3 grits.  In some areas the stuff is very hard to get.  JC Whitney and Eastwood sell it, 50lbs for $80 (plus shipping).  I have used my blaster for rust bubbles on panels, the inside of the ashtray on my '57 oval, a metal brake fluid reservoir, and stuff like that.  Anything larger I farm out to my shop.

I paid the sandblasting shop about $650 for the work on my '57.  Now that was the entire body, inside and out, top and bottom, except the areas inside covered by carpet and headliner.  Dash, fenders and lids, both sides; doors, all but the inner cavity; plus a spare gas tank and a spare decklid.  Money well spent in my book.  See page 9 the '57 Resto Anthology for pictures.

There are other blasting abrasives out there that some shops use.  Soda blasting is very popular, it is a very fine powder that pits the metal very little.  But I have heard that some sodas are technically salts, that can get embedded in the metal and cause rust under the paint later.  One shop in Rhode Island, I heard through the grapevine, went out of business after millions of dollars of damage lawsuits came their way.  I doubt that is true of all soda blasting, but do your homework.

Crushed walnut shells are also used as abrasive blasting media.  Mostly they are used for engine and machinery stripping though, where errant, left-behind particles will break down and not harm machined metal surfaces.  They are expensive and there is no reason to use them for car body panels.

But overall, whole car stripping aside, sometimes you just have to strip one small area to address rust (especially if you are going to spray over original "factory" paint).  Here's another pic of my '85 cabrio, detailing close up of a patched perforated area.  For this I used only my angle air grinder with a grinding disc.  This newly patched area is roughly ground down.  It will be sprayed with etching primer sealer (as will the entire car), but will not need to be "finished" as the wheel arch molding covers up this area.  The back side was wire brushed and covered with undercoating.  If you look close, you can see another area that was patched at the extreme lower front end of the arch.

Tools- Compressor

"How big of a compressor do I need to paint a car?"  This is a common question.  Well it all depends on the paint gun you will use, and possibly any air tools that you may use to prep the car.  Compressor outputs are rated in cubic feet per minute (CFM) at a given pressure in pounds per square inch (PSI).  Air powered device air requirements are usually spec'ed the same way, in CFM at a given PSI.  Most spray guns of any kind operate in the 10-50PSI range.  Compressor outputs are almost always specified at 40, 90 and for bigger units, 175 PSI.  You want to insure that the rated output of the compressor you use is at, or preferably above, the air volume requirement of the gun.

Well how big of a compressor?  How many horsepower?  How big of a tank?

Well, to understand the relative function and effect of the compressor components, think of a compressor as a water pump and a big barrel.  The horsepower spec determines how much water the the pump can move, let's say in gallons per minute (analogous to CFM).  The barrel determines how much water the thing can "store up".  Now lets say your pump is rated at 10 gallons per minute, and you have a 100 gallon tank.  It will take your pump 10 minutes to fill the barrel (this calculation has little relevance to the compressor example, as the water isn't actually being compressed and the pump output rate isn't affected by the amount of water in the barrel).  The pump shuts off when the barrel is full.  Now lets say that you have a "tool" that uses 5 gallons per minute, and you attach it to a spigot on the bottom of the barrel.  Once you start using it, the water level in the barrel falls and the pump starts again.  But since the water going into the barrel is going in at 10 gal/min, and the water going out (what your tool is using) is at 5 gal/min, the pump easily refills the barrel and shuts off when it is full.

If your tool uses exactly 10 gal/min, the pump will kick in when the water level falls, but since the input and output are equal, the pump will run continuously while the tool is being used and the water level will not fall.

But if a tool is connected that uses 20 gal/min, the water level will fall, the pump will kick in, but since the tool is using water from the barrel twice as fast as the pump can return it, the water level will fall in spite of the pump running continuously, and eventually the tool will run out of water to use.  But you can actually use the high demand tool for a short period of time, and/or intermittently.

That is an over simplified example, but it helps explain the principle of the compressor and the relationship between pump output (usually directly related to horsepower).  Compressor put output actually falls off as the pressure in the tank builds.

What you need to keep in mind though, is that a spray gun is a continuous use type tool.  Like a sand blaster and a "DA" sander, it uses a steady stream of air.  Many tools are intermittent use tools, like framing nailers, impact wrenches and air hammers.  What this means is that a compressor with a sufficiently large tank, can easily operate a tool that requires more air (CFM) than the pump can supply, if the tool is used only intermittently.  But for continuous use tools, an adequate CFM rating is required, and a large tank really can't make up for any shortcomings there.

So what size compressor are we talking about?  Well, let's look beyond spray painting, as a compressor is a tool that will be used for many other things and is a good investment (tell your wife that).  Most "do it yourselfer" type intermittent use air tools like impact wrenches and air chisels will use around 4 CFM at 90psi.  A 4 CFM compressor may be as small as 1.5 hp.  But you wouldn't want to buy a compressor with the bare minimum you expect to need.  My recommendation is that a minimum sized compressor for home use should be 6-7CFM at 90 psi.  This would be a 3-5 hp unit.

Now paint sprayers require a wide range of CFM, depending on type.  It used to be that HVLP (high volume, low pressure) paint guns needed massive amounts of air, like 15-20 CFM, but only at 10-30 psi.  Note that the CFM/PSI curve of any compressor is not linear, but you can extrapolate the values out a bit.    If the compressor you are eying is rated at 6CFM at 90 psi, and 8.5CFM at 40 psi you can make a graph to estimate what it might deliver at 20 psi for example.

So in this graph, it should be clear that the compressor would probably deliver 9 CFM at 10psi for example, or about 7 CFM at 50psi.  The curved blue line is, at least in profile, more like the actual CFM/PSI response curve of a compressor.

A 3-5hp compressor with a 25-35 gallon tank is a good homeowner unit, and can be purchased new for around $350.  In my opinion (and order of preference), Ingersoll-Rand, Cambell Hausefield and Sears are good brands.  One mail order tool outfit who sells a good selection of compressors and will ship them for free (yes, free), is Harbor Freight Tools.

If you will be using more air, possibly with larger scale sandblasters or more demanding spray guns, the next step up in compressors is usually to a 2 stage and possibly 240 volt unit.  Yes, you can get single stage units on big "fat boy" tanks up to 6-7hp, but the realized increase in CFM is seldom worth the added cost over the $350 units.  Once you get to the 2 stage units (most all of them 240 volts), you see a huge increase in CFM (11CFM at 90psi and up), an increase in max psi (up to 175) and of course, an increase in price (usually start at around $800).

Tools- Compressor Lines

Air quality is very important to a quality paint job, and your two enemies are water and oil.  Oil may be in your air lines if you use an in-line oiler and air tools.  I use an oiler at my regulator station.  For this reason, my hoses invariably have oil residues in them.  So I have a "paint only" air hose that I use for spraying, and connect it only to an air tap after the regulator and before the oiler.

A good way to get water out of your lines, especially if you live in a humid climate, is to make sure the compressor tank is de-pressurized, open to air  and dried out before you use it.  A couple days before you paint your car, open the tank drain valve on your compressor and leave it open.  If possible, open the pump outlet too (you can insert a blow gun and rubber band the trigger).  Don't pressurize the tank until an hour or so before you expect to spray.

And another neat trick, I learned from Thom Fitzpatrick; if you have an extra long spray hose, coil it up in a big washtub, and fill the tube with ice and water.  This will act as an "intercooler" for the lines and will wring moisture out of the air before it reaches the gun.

Tools- Spray Guns

Inexpensive spray guns that will do a decent job are available for around $50.  Professional guns cost around $500.  I have used a couple "old fashioned" suction feed gun as well as a gravity feed HVLP gun.  I also have a small suction feed "touch up" gun.  I find the HVLP gun to be much easier to use and more predictable.  Harbor Freight sells a DeVilbiss "clone" HVLP gravity feed gun for around $50, I have one and used it to paint my Cabriolet.  Their product number is 43430.  The air consumption of the gun did tax my 3.5 hp compressor a bit, but I could easily pause for a minute or so and let the compressor "catch up" when I needed to.    The air consumption spec on this gun is 9.5-14.8 CFM at 15-50 psi.  I think I ran the gun at about 40 psi and my compressor is rated at 8.5 CFM there.  The gun has a small regulator and gauge at it's base which is very useful.

My HVLP gun is shown in the pic on the left (click on it ot see a bigger image).  The little white ball looking thing at the very bottom is a "last chance" filter and water trap.

Using the spray gun and cleaning it properly, are challenges unto themselves.

How They Work

Most all spray guns have two stage triggers.  When you pull the trigger a little bit at first, air flows from the tip, but no paint flows.  Pull the trigger farther, and paint begins to flow.  You can "feel" the added load of the second stage when you pull the trigger.  All the guns I have used have had adjustable paint flow "pins" on them (the pointed steel rod that obstructs the paint tip when the trigger is released).  Opening up the paint flow tip means that more paint flows out when the trigger is pulled back all the way.  Other adjustments commonly found on guns are airflow adjusters (the regulator at the bottom of the handle in the case of my HVLP gun) and and pattern adjustments.  The pattern adjustments adjust the air "fan" pattern that directs the paint.  On my HVLP gun, I can adjust from a spot, to a tall oval "eye" shape.  I can rotate the orientation of the eye shape by loosening the collar on the tip and rotating the fan head.  It may be hard to visualize these features if you haven't ever played around with a paint gun, but when you get your hands on when, they will make sense.

And again, I am far from a paint expert, but I will tell you what my spraying technique is.  First and foremost, especially if you are starting out with a new gun, practice on something you don't care about.  Get a big sheet of plywood or cardboard and play with the patterns, air and paint flow.  Ideally, then try to paint some smooth metal so you can get a sense for how much paint you can shoot before things get drippy.  Get a feel for the 2 stage trigger action and see how adjusting the paint flow knob changes it's action points.  As for air pressure, what matters is the gauge pressure while you are holding the air trigger down, not while the gun is off.  Suction feed guns usually use about 50psi of pressure at the gun, HVLP guns vary between 10-50 psi.  Remember you are trying to strike an ideal mix of air and paint.

Too little paint, and well, nothing gets covered well.  Too much paint, and things get heavy, drippy, saggy and sputtering. Too little air often yields splattery and "spitty" paint coverage (not enough air to atomize the paint and carry it through the air).  Too much air and the paint "scatters", is all "rough" and misty at the edges of the spray pattern.  You really just have to play with all the adjustments until you get the results you want.

One common problem with my suction feed guns was when the cup air inlet hole got clogged with paint.  When this happened the output got real spattery.  Took me a while to recognize this symptom and correct it.  If you use a suction feed gun, keep the air inlet hole (usually a very small hole on top of the gun cup "cap").

When painting a car body, a vertical "eye" pattern, with a sharp cutoff at the edges usually works best.  The pattern should be convex, with slightly more paint in the center than the edges. The idea is with a 1/2 overlap, on successive passes, you evenly distribute the material.  Don't stop the gun pass at the edge of the panel or area to be painted, go past it.  This is important to insure uniform coverage.  Go left and right only, no zig zags, cross hatches or "outline then fill in" techniques.

And lastly, here is an important tip I learned from my body shop owner friend.  As you paint, get used to keeping the air flowing at all times.  Feather the trigger on and off on it's last little bit of travel to turn the paint on and off, but keep the air flowing and keep moving the gun past the newly painted panels.  What this does is keep an airflow across the painted panel.  This helps evaporate the solvents out of the paint faster and reduces the chance of sags and drips.  Know what I mean?  Just don't let off the air, after you have painted the panel, keep "spraying it with air" for a minute or two afterwards to help the paint set up faster.

Setting up and Cleaning

First and foremost, understand that using (that is filling, spraying and cleaning) spray guns is very time consuming.  It is not something you do "in a pinch" or in a spare 15 minutes.  Filling and cleaning the guns can be very frustrating and messy.  The first time I did it, I couldn't believe what a huge mess it all was.  But watching my friend Tom work, and learning a few tricks along the way, I got pretty good at it.  First of all, make sure you have the following materials before you even start:
  • A gallon of fresh clean thinner.  The solvent that is made to "cut" the paint that you will be shooting, you should get it at the same place you buy your paint.
  • A clean, glass kitchen type measuring cup (yes, BUY one, don't steal the wife's!!)
  • A stack of clean, large (like 12 oz or better) paper or plastic cups.  If you use plastic, test one first with your thinner to make sure it doesn't dissolve it.  Some cheaper plastic cups will dissolve.
  • Paint strainers, a box of them.  Cheap, get them at your paint supply store, and I think Harbor Freight sells them. (see pic above)
  • A whole bunch of clean popsicle sticks or something else to stir paint with and dispose of.
  • A bag of latex painters gloves.  Home Depot sells a bag of about 100 for cheap.  Harbor Freight does too.  Get them, very important, keeps skin oils off freshly prepped surfaces too.
  • A large jar or can to pour waste solvent into.
  • (for HVLP guns) Some kind of rig to hold your gun while you put paint in it.

  • You must get all these things together before you start painting or the whole thing will be a disaster, trust me.  And setting up to shoot paint is a time consuming procedure, do not rush into it or start when you don't have ample time. 

    Auto paints are nasty stuff, and those latex gloves really save your hands, use them.  Thinners will remove any trace of oils from your skin, and your hands will be dry and cracking for days, even with lotion on them.  The gloves are dirt cheap and easy to put on and take off.  I got some really cheapy paint strainers from Whitney or Harbor Freight, and would use two at a time (stacked) just for good measure.

    The rig I made to hold my HVLP gun (click on the pic on the right) was basically a big wooden two prong fork that was screwed upright to the forward edge of my workbench.  I could slip the gun down in the notch, with air hose connected or not, and it would hold it upright while I filled it.  Work out some kind of solution like this a day or so in advance (the body shop uses little formed plastic "holsters" for the guns), dropping guns and spilling paint is no fun.

    Most all paints will need to be mixed with something, either a reducer and or hardener/catalyst of some kind.  And the volumes will have to be measured.  I really don't like creating waste, but I found using throw-way plastic cups to be very efficient and fast.  You can mark translucent ones with a marker, or use a glass one for measuring.  Either way, mix the stuff per the manufacturers directions (with mask and gloves on!) in a disposable cup.  I learned by where the ridges are on the plastic cups, if they have them, what is 100% and what is 50% for a 2:1 mix ratio.  Another way to do it if your cups have no reference ridges is to mark a "master cup" (use measured water to insure the volumes are correct first, like pour 6 oz in, mark level, then pour 3 oz more in, mark level, for a 2:1) then each time, slip it into a new cup, hold it up the to light, and mark the outside cup with the marker and use it.  I would pour the clear reducer into the mix cup first, then the paint from the can, referencing the marks on the side.  Do not get reducer (or catalyst/hardener) in your paint can!!  Stir the paint with a popsicle stick, place a paint strainer (a paper cone with a gauze/mech cloth over a big hole in the bottom) in the paint gun cup and pour the mixed paint in the strainer to fill the gun cup.  Throw away the popsicle stick and used cups.

    A note about paint "pot life".  It varies by type and manufacturer, but usually non-catylized paints have pretty much an infinite pot life.  Paints that are just mixed with reducers or thinners are usually like this.  You will find "Pot life" specs in you paint manufacturers reference book.  Ask at the paint supply store if you don't know.  If you have a paint with a short pot life, you want to make sure you know this in advance so you can use all that you mix (and this may be a factor in how much you mix at once) and not have it start to harden in the gun.  And again, be warned that some urethane primers cannot be cut by thinner once they harden!

    Now, about the cleaning part.  First of all, all guns are different.  Refer to any documentation you may have about yours with regards to cleaning, or at least disassembly.  Do this well in advance of putting any paint in the the gun.  Usually, you want to clean any part of the gun that comes in contact with paint.

    My goal is always to clean the gun thoroughly with as little thinner as possible.  Here is the basic procedure that I use with both my suction feed and HVLP gravity feed guns:

  • Put my mask and goggles on if they are not on already
      • Remove the paint cup, place it upside down on the paper cup/strainer that I used to mix the paint previously to let as much of the leftover paint drip out.  If you have few ounces of left over paint and it is non catalyzed, you can pour it into a baby food jar and keep it for touch ups later.  Whatever you pour it in, try to absolutely minimize the amount of air that is in there with it when it is closed.
      • Take the cup off, and for suction feed, hold the intake tube on the gun over the strainer/cup and pull the trigger, this lets any paint in the passages backflow out.  For HVLP/gravity, point the nozzle of the gun down over the cup, pull the trigger.
      • Dump about 2 oz of thinner in the cup, and slosh it around.  For the HVLP/gravity cup, I hold a finger under the bottom hole.  The goal is to get most of the leftover paint thinned out and removed.  If the outside of the gun is really drippy, I put a paper towel in the cup, soak up some thinner and wipe down the outside.
      • Dump the thinner in the waste can.
      • Wipe out the cup with a fresh paper towel (OK to still have paint smears in it)
      • Put another 2 oz of thinner in the cup, put it back on the gun.  Hook up the air and spray holding a rag or paper towel in front of the nozzle (mask and goggles!!).  Watch for the spray to become "clear", with no paint color in it.  For clearcoats, just run the gun for about as long as you did for paint.  Usually at the end of this procedure, I grab a fresh paper towel and spray it, then...
      • Use the thinner sprayed paper towel to wipe down the whole gun, handle, nozzle area, anywhere there is paint.  If you have paint on your gloves, wipe them too.   This is the final wipedown, clean counts.
      • When you are done with the outside (use a fresh paper towel if needed), take the gun off the cup, stick the paper towel in, soak it and wipe up the cup real good.  For suction feeds, make sure the top lip of the cup where it mates with the cap is clean, as is the air inlet hole and surrounding area.  Everything should be clean.
      • If this is the last gun clean of the day, I take the nozzle off, take the paint control pin out and clean it with a thinner/rag.  Hold your air nozzle up to the light and make sure all the tiny air passages are clear.  Lastly, put the blow gun on the air line and blow out the nozzle and cup.

    Important note: Some catalyzed primers and paints (the "HS" primer Spies-Hecker I used for one) will not breakdown with thinner once dried.  It is very important that you clean these guns immediately after use.  If the paint hardens in them, they are junk and you have to buy a new one.

    Mask (and other safety considerations)

    Yes, you must have a mask, and more than those "nuisance dust" kind.  Auto paints contain solvents and compounds that will seriously affect your health, even if you just breath the fumes once.  But you can get a good mask for cheap.  The stuff you should be particularly cautious of are two part paints containing isocyanates and hexamethylene diisocynates.  The catalysts used in these paints usually contain diisocyanate prepolymer, and it's the that is the main concern. It attacks the central nervous system, and can cause permanent injury. A good air flow, and a fresh air mask should be used. If you don't have any bronchial problems, then an activated charcoal mask can be used.  Make sure the mask you use states that it is intended for these paints, if you are not sure, ask at the place where you bought it.

    I bought a disposable 3M mask at my local autobody store.  It was charcoal activated and was good for 30 hours of "out of the bag" use.  It comes in a resealable ziploc type bag, and is effective as long as it is not out of the bag for more than 30 hours.  It cost about $18.  It has a large rubber mouth/nosepiece fit very well and was very comfortable.  With the proper mask, you should be able to smell nothing.  I can wave a dripping, thinner soaked rag in front of my face with my mask on and smell nothing.  I think I figured I used only about 5 hours total of mask time when painting my car.

    A fresh air mask is a ventilation system that usually has a full hood and a pump, placed outside the painting area, that pumps fresh air to the user.  These are the safest systems, but can be quite expensive.

    NOTE: There is some discussion as well as some disagreement among painting professionals about whether these kinds of masks are acceptable for use with paints containing isocyanates.  I will tell you that I called 3M and asked them about this specific mask and the guy said that it was appropriate for use with isocyanate paints (virtually all urethane paints contain isocyanates), but to be honest, he didn't give me a great deal of confidence that he knew what he was talking about.  You make your own decision.  As I paint very infrequently, I have made the decision for myself that this mask is OK based on the information that I have.  For more info in isocyanates, see this website from NIOSH on "Preventing Asthma and Death from Diisocyanate Exposure", and as always, remember that you are responsible for your own actions.


    Sanding is probably 50-70% of the prepwork for painting a car, and after you do it, it will seem like it was more like 98%.  Sanding is the resurfacing of body panels, making them progressively smoother by rubbing an abrasive sheet on them and removing material..


    Aluminum Oxide is usually best, it is cheap and it holds up well to wet sanding.  It is the black faced stuff.  It comes in various grits, represented by a number.  The higher the number, the finer the grit.  Depending on your job, you may use grits from 80-1500.  If you are going to buy some sandpaper and want a good "set" of grits, get 80 if you will be doing any powered stripping (like a round pad on a DA sander), else get 120, 220, 600, and 1200.  If you ill be using a DA sander, those adhesive backed discs are really good, quick and easy to change and very effective.
    Sanding Tools
    The "DA" sander is the bread and butter surfacing tool of the body shop.  It is an air powered sander.  If you have compressed air available, you should get one.  Harbor Freight sells a good Ingersoll-Rand 6" one for around $50 if you can catch a sale.  I had one of those Chiwaniese made $19.99 ones (4CFM @ 90PSI) for a while and it was pretty worthless.  Beware, these sanders can use a lot of air, check the specs and compare to your compressor output.  My 6.8CFM @90PSI compressor cannot keep up with my I-R sander (rated at 4 CFM "average" air consumption by the way)  But if I take occasional rests allowing the compressor to catch up, it works ok.  Some 8" DA sanders require 15-20CFM at 90PSI. 

    "DA" is for Dual Action.  The sander pad gyrates around a pivot about 1/2" off the center of the disc, and the disc itself rotates about its axis.  This may be hard to understand without seeing the sander up close, but what it does is insure that the sanding pattern is truly random and does not leave swirl marks.  DA sanders are great for stripping paint to bare metal with 80 grit paper.

    Can you use an electric wood workers sander?  Well, yes, but it is not ideal, in fact it is pretty poor.  The stroke length on them is usually pretty small and they will not be nearly as effective as a good DA sander.  I have used them (in my pre-air days) with only limited success.

    Sanding blocks are another staple in the body shop.  They are rigid or flexible tools that you can wrap sandpaper around and use it to sand panels.  But since very few auto panels are flat or close to it, they have limited use.  There are some flexible, rubber blocks that are pretty good for roofs, hoods and such, but hand sanding is still needed.  Too large and or two rigid of a block will tend to sand down, or reduce the "crown" (upward bubble or curvature) of a panel.

    Scotch-Brite (3M) pads are a recent abrasive tool/material that are really handy.  They are basically like thin, abrasive mesh pads that can be used for sanding.  They tend to last much longer than paper, don't hold media and clog up like paper, and can conform to irregular surfaces.  They come in different "grits':

    • Coarse, brown  07480
    • Medium, maroon  07481
    • Very Fine, blue  07515
    • Super Fine, gray 07516
    Search the web on those numbers and "3M" and you should find some suppliers.  Also, my local Home Depot has started carrying smaller bundles of at least the medium stuff in the paint dept.  They can also be used wet.
    Wet Sanding 
    "Hold on a second.  Doesn't sanding infer paint prep and bare metal?   Harmful to unpainted surfaces?  WATER!?"

    That is what I used to think.  Well, you do have to keep the water wiped up especially where there is bare metal around.  But why "wet" sanding?  It is because when you get to the finer sandpaper grits, basically anything finer than 220, the media dislodged (the "dust") collects on the surface of the dry sandpaper and immediately clogs it up.  This is called sandpaper "loading" by many body guys.  Start and real soon you are just rubbing compacted dust on your panels.  By wetting the paper, and the panel, you allow the media to be rinsed away as you sand.  It actually works very well.  Also you get a better view of the sanded area (the sanding dust is rinsed away).

    Make sure the sandpaper you use is specified for "wet sanding" use.  Most aluminum oxide, fine grit papers are.

    Hand wet sanding is a skill that every body man has.  Here is the way it was taught to me.  First, start with a piece of sand paper about 4" by 6" (roughly 100mm x 150mm).  Now fold it about one third of the way from one of the short sides.  Take any rings off your sanding hand that you might wear.  Hold your hand out, palm down, flat. Put the larger section of the paper across your upper palm (NOT your fingertips), and the shorter folder part sticking up alongside your lower index finger.  Now close you thumb in against that shorter folded part, using your thumb to hold it against your index finger knuckle.  Dip your hand into a bucket of clean water, and sand the panel.  You might want to pre-wet the panel with a spray bottle of fresh clean water.  Sand with your open palm and do not use your finger tips.  If you did exactly what I described, and the paper is no more than 4" on the short side, it doesn't even reach to your fingertips anyway (unless you have really small hands).  Your fingertips will apply too much "point pressure" on the panel, you will not get a smooth flat sand.  You should be using your upper palm and the inside faces of your lower fingers to apply pressure to the back of the paper. 

    With everything nice and wet, the paper should glide smoothly over the panel.  It may not seem like you are sanding at all, especially with 600 grit or finer.  But don't press too hard.  Use your other hand to wipe the panel (rings off!) after you sand, you should see media on your hand.  When you get going, you should work up a nice "sludge". Sand until you don't see any orange peel (it shows up well when the water dries) and small imperfections are smoothed out.  Use the edge of a rubber sanding block to squeegee off the excess water, or wipe with a rag.  If the water you are using has a high mineral content, don't let it dry on the car. It could leave spots which may bleed through the new paint.

    Now if the panel suddenly grabs the paper and strips it from your moving hand, the panel has just become too dry, you need more water.  Rinse your hand and the paper in the bucket every 30 seconds of sanding or so.  Replace the water if it gets really cloudy.  On a cold or cool day, use warm water.  If your hands tend to dry out easily (this will make them dry out even faster), you might want to use a pair of latex gloves.

    Wet sanding with Scotch-Brite is similar, although they don't need to be rinsed as often.  You may have to use your fingertips a bit in crevices and near abrupt body panel contours.  When you are done, dry everything thoroughly with clean cotton rags, use compressed air to blow out small crevices and holes.  Pay special attention to bare metal areas.

    Guide Coating
    This is a well known trick in body shops to help you see just how much media you are sanding off, and is usually done on those ultra picky paint jobs.  The idea is after initial primering and sanding, to spray a thin layer of a paint that contrasts with the primer color.  If you are using white or any light primer, black works great.  Darker (red?) primers, white works well.  My body shop owner friend says that any cheap 99 cent spray paint will do.  He just mists a light, not-necessarily-uniform coating on the panel.  No get your gun ready and spray another full coat of primer over that.  when dry start sanding.  As soon as you sand through your new coat, you will begin to see the contrasting guide coat coming through.  Stop.  You don't want to sand any further there.

    This works very well for large, nearly flat panels and using rubber block sanders.  It will help you find subtle high and low spots that I guarantee you would never see until you had that final super shiny clearcoat on and thought you had sanded perfectly.

    Here's some more pics of the '85 Cabrio.
    In this picture, the stripped areas of the body have been skimmed with Evercoat's "Rage" filler.  I'm not going to get into using filler here (see my "#4 Resto" pages for some detail on that) but I will say that because I was using a a high solids ("HS") primer surfacer, I didn't need to use a glazing putty over the filler.  The front wheel was removed only to allow easy access to the back side of the wheel arches.  You can see that the whole side panel has been sanded and that new layers of filler have been applied.  Applying filler is often a multi-step process.  Also note that the bumpers, grill and fascia inserts have been removed.


    Masking is the application of tape and paper and other blocking materials over areas that you don't want to get painted; and it is a science unto itself. 

    Rule #1: Always use fresh masking tape.  Perhaps you didn't realize that masking tape was "freshness dated", but it is.  No, it doesn't have a "best if used by:" date stamped on it, but it does get old.  Old masking tape may seem OK, but it is less flexible, hard to get off the roll in a length without it tearing, and perhaps most importantly, the adhesive has dried out a bit, it will be harder to remove and it may leave adhesive residue behind.  You don't need this headache, buy a couple fresh rolls of tape.  And yes, you can get "ordinary" masking tape at Home Depot, it will work just fine.   1" and 2" wide rolls seems to be good choices.  You will use a lot of it.

    Rule #2: Masking off an entire car, even if you took almost everything off the outside, will take a long time.  Depending on your project, it may take as long as the panel sanding and preparation itself.  Don't rush into this.  Look at your car, and imagine you are airborne paint droplets, and you are free to go anywhere you want.  You will go anywhere you want.  Overspray on wheels, interiors, door jambs, engine bays, wheel wells, etc. looks terrible and is the mark of a truly amateur paint job.  Take you time, mask off everything.

    So what to use for masking paper?  Well, here's something that worked well for me.  I bought a table top masking station from Harbor Freight, with two rolls of masking paper for around $32.  Did it work well?  Well yes, but only after some serious modifications.  As expected, this thing was a Taiwanese piece of crap and required serious re-engineering.  Wing nut ears crumbled and broke off in my hands.  Now as I write this, I don't really recall exactly what I re-engineered on this, but click on the picture for a full sized image and you can see how I set this thing up.  I think I might have actually re-located the tape reels or something and used my own piece of threaded rod.  I just remember some cussing.  Once I got it working, it worked well but needed one other mod.  It needed to be clamped down to some stationary surface.  The idea is that you grab the paper edge and just pull off a length, taped along both edges, and with a twist and pull, you tear it off like wax paper from that box in the kitchen.  But you have to pull pretty hard, and the weight of the station itself isn't even close to being enough to hold it still.  I clamped mine on a reasonably heavy rolling table but still had to put my foot on the table base as I pulled to keep the table from following me.  Plan on clamping this thing to a fixed workbench or bolting it to the floor somehow, you life will be much easier. And i just went to the Harbor Freight website to see if they still sell these.  I only saw a couple "floor standing" kind.  I can assure you that they too will not stay stationary when you pull paper off, plan accordingly.

    What is special about the paper?  Well for one it is cheap and roll goes a long way.  I bought two rolls for a bit over $5 ea., and in spite of having to cover a whole convertible top, still only used one roll doing my Cabriolet.  This paper is heavier than newspaper, and has a light wax coating.  This keeps it from absorbing water that might splash on it when you do any final wet sanding after masking.

    I mention this masking station in detail because I absolutely cannot fathom painting a car now without one, that is trying to tear, cut and fit newspaper by hand instead.  It would have taken me ten times as long to do the masking.  In spite of the headaches getting it all working, it was well worth it.  So you can learn another few things here and maybe get through it a bit faster than I did: 

      • If you get one, take the time a day or so before you start to get it assembled and set up.  Make sure you can pull off paper easily and the the tape applies itself evenly along the edges.  Plan on an evening just to do this.
      • Figure out a way to clamp or bolt it down securely. 
      • Buy a couple fresh rolls of 1" wide tape for the station, mine didn't come with any, and you'd want fresh tape anyway.
      • Get two rolls of paper when you order the station, they are cheap and you don't want to run out

    Masking the '85 cabrio....

    No, I didn't put all that filler on the hood.  I have long suspected that this car had an engine fire before I bought it, there are many layers of filler and primers on the hood.  But here you can see that masking has begun, and as stated above, the paper dispenser is invaluable.  Note that there are no flaps on the windshield, every paper edge is taped down.  Also note that virtually everything has been removed from the grill, cardboard is used to block off the lower fascia holes.  The hood is propped up to allow painting of the hood side edges as well as the upper fender edges inside the engine bay.  You may see a lot of filler, but nowhere is it more than about 3/32" thick.
    Masking the door openings proved a bit challenging but not all that hard.  I took the doors off to make it easier to work on them (laying them flat on a rolling table) and to make spraying the door jambs easier.  The sill panels and edge welting have been removed and the carpeting rolled back. Again, note that there are no loose flaps, every edge is taped down.  If you look real close, you can kind of see the "lifted" edge of the windshield seal lip, the cord is under there.  There is still lots of filler and finish work to be done to this side of the car at this point.
    At this point, the car is nearly ready for primer.  Note that the whole top is masked off as are the wheels.  The rocker panel paper "skirts" are in place and the doors and deck lid are prepped and ready to be painted off the car.  The red primer you see on the rear wheel arch (this one was pretty wrecked) is Spies Hecker's "Red-Brown" anti corrosive primer.  It can be sprayed on bare metal, but it cannot be sanded and finished.  So it is only used sparingly in places that will be covered  by arch moldings or where the finish is not important.

    The Spray Environment

    Hopefully it goes without saying that you want as clean an environment as possible to spray in.  Personal safety considerations aside (like mask, gloves, goggles, etc.), you should have three main objectives:

      • Reduce if not eliminate foreign airborne particles 
      • Insure proper ventilation
      • Control temperature
    So you don't have a professional down draft spray booth, huh?  Neither do I, but I have been in one several times and studied it.  A down draft spray booth is basically a sealed "garage" like structure with large doors at one end.  It has a ventilation system that draws air from vents at the top, center of the box, to vents along the bottom of the side walls.  Thus, any airborne particles are drawn down towards the floor.  Both the incoming and outgoing vents are filtered.  The booth also has a heating system that can crank up the temperature to 110-140F very quickly to "bake" the paint.

    So let's look at your situation.  Can you paint outside? Of course you can.  But what control do you have over the elements listed above?  Ventilation should be no problem, but other than that, you might have some real problems (Note: A freshly painted, bright yellow car attracts gnats in droves.  Ask me how I know).  Painting outside is seldom ideal over any indoor options, but, if you truly had to paint outdoors...

    You would want to have a surface for the car that is virtually dust free, pinning a large plastic tarp down would be a good idea.  You would want a warm day, preferably 70-80F, and virtually no wind.  That, I think would optimize outdoor painting......

    The "garage" spray booth

    Creating a decent spray environment in the garage you normally park cars in and work in is a challenge, but it can be done.  Rule number one is that dust is your enemy.  Any kind of light, small particle.  Remember, you will be spending a few days just shooting streams of air all over the place.  So job number one is to start by eradicating as much of it as you can.  Get out your shop vac and start in the higher areas first.  Shelves, hanging light fixtures, work surfaces, kneewalls.  Look for the areas that are least used.  When you are done, give the floor the weeping of a lifetime.  If possible, spray it out with the hose.  But keep in mind that if you are going to spend a few days sanding primer and filler in here, you are going to be creating a lot more dust, so you will just have to do this all over again if you aren't ready for spraying.  Best to do the "big clean" right before you spray.

    I have heard of folks draping the garage walls with plastic sheets and tarps, but I took one look at my garage and came to the quick conclusion that it would far easier to just give it a good clean.

    Make ample space to work in.  Consider moving stuff out of the garage you might not have ordinarily thought to (you might be removing some dust in doing that!).  You will ideally need about 4-5 feet of space on all sides of the car to get you, a spray gun and an optimal distance from the gun to the car in.  I have seen pics of people spraying cars in garages with barely enough room to walk between the car and wall, but I'm sure the results suffered somewhat.  Make all the room you can.  If you can't move it outside, but have some floor space to work with, move it all in a pile and cover it with a plastic tarp.

    Preparation, preparation, preparation

    Ok, we've covered taking stuff off, sanding, masking, setting up the gun.  Let me mention some final preparation details that I haven't already.

    First examine every single square centimeter of every panel you will paint.  I can't tell you how easy it is to miss a filler edge, or ding dent, or coarse paper sanding mark.  Examine everything, slide a bare hand over it slowly.  Now go get another light source, like a drop light, or even a table lamp without a shade.  Plug it in and walk around the car with it.  Lighting can hide imperfections, no matter how good the light in your shop is.  Carrying another light source around with you when you do final inspection can really uncover areas that you might have missed.  Move the light source back and forth.  Now, put the light down, and go in the house.  Have a cup of coffee, a Coke, dinner, watch TV, do something else for a while and "turn off" your painting thoughts.  Then after and hour or two, go out and inspect again.  The mind has a way of masking out things we ordinarily would know are wrong if we just stare at them continuously (ask me how many times I have proofread stuff I write half a dozen times, only to upload it to the web, read it an hour later and see all kinds of errors!!).

    If you stopped short of a panel edge in doing your fine finish work because some body molding or trim "will cover that up", go get that body molding and hold it up there, and make sure it actually will.  I have more than once neglected to finish and area because it will be a "not seen" only to find after the paint dries that it is!

    Go over your masking work again.  Look for loose tape, open pockets or holes, missed areas.  Again, imagine that you are a high velocity, airborne paint droplet.  You can go anywhere!  Make sure that all edges of masking paper are taped down, and that there are no flaps or pockets.  Why?  Because you will spraying air, and air can easily catch a flap and flip it back over fresh paint.  And, flaps or pockets can catch air and trap dust particles that might get blasted out later.  Tape every edge down! Remember, pockets and cavities in the paper is bad.

    Mask off the wheels, then tape "skirts" along the lower edges to the floor, leaving a good 6" of paper laying on the floor.  You don't want air from the gun to pass under the car because it can catch and blow up dust particles and crud that is under the car.  This is one of the finer details of masking.  See the pictures of my Cabriolet all ready for spraying.

    Now, if you have a garden sprayer (pressure bottle), go full it with fresh clean water, and adjust the nozzle to produce a fine mist.  Then wet the floor all around the car, including the paper skirts.  "Stick" them to the floor with water.  Why?  Airborne particles that get down to the floor will get stuck in the water and won't get in your paint.  This works especially well in a down draft booth.  If you don't have a bug sprayer, a hose with a sprayer nozzle carefully feathered for a fine mist will work.  Do this before the final wipe down of your car.

    Just before you are ready to spray, get a clean, lint free, dry cloth and wipe down your whole car.  Shake out the cloth real good, then do it all over again.  Then, put the air gun on the air hoes, dial up about 40 lbs of air, and blast off the whole car.  Do this while the floor is wet!  Do not use more pressure or get the blow gun too close to masked off paper.  You might tear holes or pull the tape loose. 

    Did you read the compressor stuff above?  Don't forget to depressurize and drain your compressor's tank a couple hours before you spray and then pump it back up again.  This will reduce the amount of potential moisture in the lines.

    You want to know how dust free your environment is now?  Turn off the lights in the garage and flip on a nice bright flashlight, point it straight up, hold it in front of  your eyes about a foot away and look into the beam.  See any particles floating around?  I'm sure you will see some.  If you just blew off your car with the air hose and you now see hundreds and thousands of particles in the air, you will get hundreds and thousands of particles in your paint as well.  As a benchmark, try this outside, at night, in the yard.  You'll be amazed at what you see...

    Lastly, before you spray, you want to have your work space as well lit as possible.  Get every light you can plug in (and have it still out of the way) and turn it on.  Bounce some lights off the ceiling if it is a bright color.  A mix of flourescents and incandescents works well.   You simple can't have enough light.

    Jambing and Transition Areas

    Now we already covered some basic spray gun stuff, but where do you start once the paint is loaded?  Well, this requires a little thought and a little planning.  Fully painting a car is a multi step process and the first spray step is called jambing.  No, this isn't turning up the radio real loud when the Black Crows comes on, jambing comes from the term "door jamb" and refers to the painting of those "in between" areas.  Open you car door, see the areas that the door closes against? Top, bottom and sides?  Open the trunk and hood, see any more?  What about the whole trunk area?  Didn't think too much about those areas did you?  Yes, you could paint just the "outside" of your car, but especially if you are changing colors, when you open the door it will look like crap.  Engine bay perhaps?

    Jambing is a pre-paint step that requires some thought an planning, and it can take quite a bit of time.  It will require you to temporarily mask off some areas and sometimes must be done a day before the final painting of the car.  The idea is to do all the "lesser seen" areas ahead of time, so when it comes to that final exterior paint, you can close all the doors and lids and just spray away.

    Here is the passenger side door opening after it has been "jambed".  Note that everything is carefully masked off (including the door latch post which is difficult to take off on these cars).  Only the base coat silver has been sprayed at this point, the white flecks you see are splatters from wet sanding the white primer after the door was opening was jambed and dried.  It is highly recommended to remove the doors to do the door jambs.  You can also see that the rest of the car has been sprayed in the white "HS" primer/sealer.

    Jambing brings up another not so obvious dilemma, one I call "transition zone perils".  That is, how can I spray one part of a panel one day, then another part of that panel the next and not make it look like a 2 step paint.  For example, how do you spray the A-pillar area of the door opening one day, and then the next the front quarter panel that meets that A-pillar area without having that transition area look like crap?  Well, there are several techniques to this that body shops use, and they can be employed all over the car actually.  And just straight masking the areas off usually isn't the best option.

    The first option, and usually the best, is to hide that transition area under something.   For example, if you were jambing an empty engine bay on a Beetle body (or just painting the upper rear apron), you would want your transition area to be just under the decklid seal, there is an area about 3/4" wide to play with there.  Same for the trunk area of a Beetle body.  You could mask if you wanted as no one would ever see that there is a hard mask line there when the car is all done.

    Another method is to make the transition zone on a hard panel curve or rolled edge.  An example of this would be the A-pillar on a Beetle.  Make your transition area the outer "sharp" edge of the drip rail that follows the roof of the car all the way down to the lower quarter.  That is, jamb paint to the door opening side of the drip edge (might have to have the door off to do this right), then exterior paint the outside.  The transition area would be right along the outer edge of the drip rail.  On a more conventional car (like my Cabrio), the transition edge of the B-pillar (door post where the door latch is) was just the where the B-pillar rolled over a 90 degree bend and became the outside rear quarter.  Not a real hard edge, but enough that unless you look close, you couldn't tell the paint was "transitioned" there.

    Other good transition places are body panel seams, or, outside the car, under body trim and moldings.

    To address the transition area, the best way is to paint panel "A" (say the door jamb/opening) trying to minimize the overspray onto panel "B" (say the exterior rear quarter panel).  Let the paint dry, then re-sand and prep the oversprayed area on panel "B".  Then spray panel "B" trying to minimize the overspray onto panel "A".

    With base/clear (2 stage) paint systems, a method that works well is to base coat the two panels in two separate steps, then wet sand the transition area, then spray it all with the clear.  You can sometimes get better transition area "matching" with clears than you can base coats.

    One last thing to mention is "soft masking". Let's say you want to paint to line where you will be transitioning.  Get a piece of paper, masked one one edge, and lay the taped edge to the right or left of you line by about 2-3 inches, with the paper covering the line (I know, this is the opposite of what you are thinking).  Now take the un-taped edge, and roll it back over the taped edge and tape it down to the paper.  This creates a rolled paper "edge" just over your line.  The  idea is that this creates a "soft" barrier for the paint.  Some will mist under the roll and when you remove the paper, you won't have a "hard" masking line to deal with.

    But back to jambing.  Come up with a plan to address all of these odd areas.  Door jambs, engine bays, trunk cavities.  yes you can leave them the original color.  If you are painting the car the same or a very close color, maybe that isn't that bad.  But painting a red car blue, you might want to think about this a bit.

    The Steps

    OK, let's summarize the steps here.

    • Wash the car!  Sounds obvious but many people try to paint filthy cars.  Clean it very well, you might want to take things off like mirrors, handles and moldings first, but be aware that you may leave holes and openings in doing so that will et water into places it is not meant to go.
    • Remove the peripherals.  Moldings, handles, mirrors, lights, antennas, bumpers, running boards, etc.  Take you time and get everything off you can.
    • Grab a coarse ScotchBrite pad and go over the whole car with it.  This will be your first chance to carefully asses avery area, remove any stubborn dirt and uncover any areas needing special work.  You might also need to get some mineral spirits to get any road tar and gunk off.
    • Wipe down the whole car with a paint prep solvent like "Prep Sol" or "Tec Clean".  This will remove any wax or silicones that might be invisibly on the panels and might affect paint adhesion. 
    • Address any structural metal issues.  cut out rust, MIG patch where needed.  Inspect all the wheel arches and lower body corners carefully, poke anything that looks suspicious with a flat bladed screwdriver.  Better to find "punch throughs" now than when the paint has been dry for only a couple weeks.
    • Address and "bare metal" areas, that is areas where you will need  to get down to bare metal to fix.  Bubbled "cancers", to-the-metal scratches, very shallow dents or dings where you will use filler (Remember: filler should never be used more than an absolute maximum of 1/8", preferably 1/16" or less.  Work the metal to within that range, then use filler!).  Pull larger dents with an Eagle at this stage if needed, or use MIG pins or slide hammers.  This is the metal work stage.
    • Skim on filler (remember to bare metal only! grind off a bigger area if needed), let cure, coarse sand, shape, then re-skim if needed.  This too is a very time consuming step, take your time here.  Sand to perfection down to a 220 grit.
    • Apply glazing compound over filler if desired and sand to 400 grit.
    • Mask the car for primer/sealer shoot, including jambed areas.  Remember etching primer sealer over bare metal, sanded filler or glazing compound or known good paint (only factory paint in my book) only!  Take your time, mask off everything.
    • Do a final pre-primer inspection (you will still be able to fix missed areas before final paint though), blow off the whole car with clean (no oil!) compressed air, sweep the floor, blow off the car again.  Wet the floor of the garage with a garden sprayer or hose.  Wipe down the car with a clean lint free rag, then again with a paint-prep solvent.
    • Set up spray environment, establish ventilation, your mask, goggles, etc.
    • Mix your primer.
    • Shoot primer, insure that you are at least shooting all jambed areas in the first stage of primer shoot if you do it.  Almost always, you can primer a whole car at once.  Consider painting panels like doors, hoods and fenders off the car if it is possible.  (Note in the pic on the left, I hadn't primered the door jambs yet, not sure why.  I think I realized too late I had to take all those stickers off the B-pillar and had to stop).  A good primer should leave a very flat kind of plastic looking surface.  Your car will look instantly 100% better in primer, but be warned, flat paint hides a lot of waviness.  You still have a long way yo go after the primer dries.
    • Wet sand the whole car with 400-600 grit.  Inspect every panel and surface.  Wipe down and respray primer if needed.  When you are happy and the whole car is sanded to glass-smooth, wipe down the whole car with a clean, wet rag, allow it to dry off, blow it off with clean air.
    • Prep your area for base coat painting.  Set up ventilation, wet down the floor.  Wipe down the car one last time with clean lint free cloth, than paint prep (make sure it can be used on your primer).  Mix up the paint and SHOOT!  Remember the "keep the air flowing" technique discussed above.  Having shot both enamels and urethanes over the years, I can tell you that urethanes are extremely forgiving and easy for the novice to work with.  But also set your expectations accordingly.  If you have never painted a car before, or even used a spray gun, don't expect a Hemmings Motor News "Best of Show" finish.  Accept your best efforts, learn and go from there.
    • Spray additional coats if you desire.  I am not an expert here.  When I painted my Cabrio, I only had enough paint for one coat, and it would have benefited from more.  Consult your paint dealer/manufacturer for the appropriate method of re-coating.  With many paints, it is usually just a "flash dry" interval, and you can add another coat.  this usually means that by the time you have gone all the way around the car, you can keep going and spray a second coat.  But check with your paint supplier and/or body shop consultant.
    • Inspect you base coat (if you are shooting clear) and  wet sand with 600, then 1200 grit before spraying the clear.  When you are happy and the whole car is sanded to glass-smooth, wipe down the whole car with a clean, wet rag, allow it to dry off, blow it off with clean air, then wipe down the car one last time with clean lint free cloth, than paint prep (make sure it can be used on your base coat).
    • Spray clear if you are using a 2 stage paint.  I found the urethane clear (Spies-Hecker "8000" clear) to be simply wonderful to work with.  My bodyshop owner friend uses it and generally sprays a light coat, lets it "flash" dry (about 10-15 mins), then sprays a heavy coat.  The stuff when dry is incredible shiny and durable.

    The verdict (what I would have done differently)

    Well, like any project, there are some lessons learned, let me tell you mine.

    1.  Trying to paint a car in along weekend was not a good idea.  I had given myself 3 days, ended up taking another day off work, spent 12+ hours each of the 4 days, and barely had a driveable car in the end.  Don't rush this.  My car required a little metal/body work, but was for from a basket case.  Nonetheless, I'd estimate about 100 man/hours to do this right as a minimum, especially if you are unfamiliar with it.

    2.  Make sure you have more than enough paint.  I only had enough for a light single coat on the 'vert (about 48 oz with hardener).  When the paint dried, I could see "thin" areas in the daylight where the white primer was showing through.

    3.  Make sure you finish all exposed areas.  I thought one place would be covered by a body molding, but didn't bother to fit it up and see.  In the end, you can see untouched filler (but painted and cleared) on one fender.

    Those were the basic mistakes I made.  But overall, I was pretty pleased with the way the car came out.  Not a show car, but it looks nice, and it was don "the right way".  And I learned a lot doing it.  I can expect this paint job to last a while (although as I type this, the '85 is for sale, I bought another Cabrio, a '91). Take your time!  taking parts off, masking, sanding, spraying.  You CAN do this yourself!!

    Other resources

    Here is a link to a great list of autobody terms from autobodystore.com.  Another one here, from Canada's "Cascade Collision services" website.

    Copyright© 2001; John S. Henry 

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