This is the left side front bulkhead, the forward end of the heater channel. Under the gas tank. With body on the chassis, the master cylinder would be just to the left in this picture (LHD). You with me? This picture isn't great, but there is rust perforation visible just on the lower, right edge.

This is after the rusted area was carefully excised out with the Dremel tool and a thin carbide disc. The rusty surface you see behind is actually the end of the heater channel. It left about a 1/4" space between it and the bulkhead panel that has been cut away. A classic body cavity situation where water probably collected and sat at the forward most point. As you can see with the screwdriver, the bottom of the bulkhead panel has also rusted through slightly, perforating the bottom. This was not discovered until I poked all around the area.

Many would be tempted to just tar or bondo this up, and that is better than doing nothing at all. But it will buy you only a little time at best.

That little bit of red paint that you can see on the left of the cavity is actually Eastwood's "Corroless" that I applied with a brush when the whole left quarter was removed. With the quarter panel removed, I had access to that "in between" space in the front bulkhead. I am not very concerned with the surface rust in this cavity because I know that this car will be babied and. if I can help it, will never even be driven in wet weather. 

Yes, this is the bottom of the body. I took this picture by laying on my back. The body is up on sawhorses about 3 1/2 feet off the ground.

I used the Oxy/Acetylene torch and some brass rod to close up those rust perforations underneath. Brazing is actually very good for doing this when the perforations are fairly small and localized. It is very important though when using brass to completely remove all of the burned "flux coating" before painting. This stuff will corrode, expand and bubble over time, destroying any paint or coating that is over it. On a fresh weld, it appears as a black or brown coating and chips off almost like glass. The whole car will be sandblasted and I will instruct the shop to pay special attention to this area to insure all the flux is removed.

This picture shows the first piece of metal that I cut to patch in. It was the "first" one because I made such a mess trying to weld it on that I ended up ripping it off, cutting more of the original panel off and making up a new, slightly bigger piece. In the end, this patch didn't go well, but I thought it was still worth showing these pictures as the correct steps to patching a rust perforated area. Those are little office supply binder clips holding the piece on, it was cut from an original panel that I removed from the nose. 

This picture isn't great, but it shows the "donor" piece all dressed for welding. The edges of it and the existing panel have been ground down to shiny metal. On the lower edge of this piece where it will sit up against the flange of the panel behind, it has been drilled to allow some simulated spot welds to be used. The area around the holes has also been ground down to shiny metal. I'm using a heavy woodworking clamp here to hold it in place.

I'm still not sure what happened, but I couldn't get the MIG weld to "take" anywhere on this panel. I kept getting "cold" welds that just popped off with a "tangggg!" when I pressed on another part of the panel. I cranked up the power on the MIG and got it to go a little better. Then I was trying to do a butt weld along the top, but the panels didn't quite meet and left a small gap. This was a disaster. I started burning bigger and bigger holes along the gap with the MIG. Finally, I just grabbed the Oxy/Acet torch and some brass rod. It is much easier to "fill in" with brass (at least for me anyway) but it also invariably warps the panels a bit too. But I keep telling my self that it was solid and nobody would every see it.

If you ever see my car at a VW show, don't ever let me catch you looking under here.