My Beetle Restoration

After a three year hiatus, I am finally back to working on this car and more specifically, the chassis. The shop is still in disarray after building out the interior, but it is done enough that I can get back to work on the 1960. This is also the parking spot for my 1973 Super Beetle that can be seen in the background of my images.

When I moved to my current location two years ago, I fastened the tunnel bottom plate down to the tunnel with self-tapping sheet metal screws to strengthen it and make it easier to move. It's been in this state until now and has been lying around in the shop. When I pulled the bottom plate back off to get started, I found that mice had been inside of it. But fortunately, they didn't cause any issues other than some poop and acorn shells. The protective coating that I sprayed on the inside also kept it them from causing any rust or other damage. I cleaned and disinfected all surfaces. I test fit the frame head bottom plate and the Napoleon hat just to refresh my memory. It will need a lot of fettling to get the pieces fitting well. The frame head bottom plate is a modern aftermarket part and is quite a bit different than the original. The Napoleon hat is a donor part from a mid-1960's Beetle and is very close to the original.

I took a couple of pics from the underside to show the fit of the tunnel bottom plate and Napoleon hat.

The next step is to weld the tunnel bottom plate back onto the tunnel.

I'm finally at the point that I can weld the tunnel bottom plate back on. First, I touched up the protective coating on the inside of the tunnel with Eastwood Matte Black Rust Encapsulator. Then, I cleaned up the areas where it will be welded.

Next, I masked off all areas where the panels will fit together and sprayed them with U-POL Weld #2 Copper Weld Through Primer.

It's been a while since I last welded and I had to buy a new welder, so I really didn't know how this was going to turn out. I started by welding the welds on either side of where I had placed the sheet metal screws. There was a steep learning curve to overcome. The holes that were created with the spot weld cutter were huge (3/8"), and many were very close to the edge of the plate. Getting the welds hot enough to penetrate the 2-milimeter plate and fill the holes without melting away the thin outer edge was very difficult. Fortunately, the replacement rails were quite a bit wider so if the welds did melt the outer edge away and spill over, it shouldn't really cause an issue as the rails will be trimmed back when I fit the floor pans. Out of curiosity, I counted the welds on each side - 63 on the driver side and 76 on the passenger side. I took my time and made sure that I didn't get the metal get very hot. After doing all of the spot welds, I ran a straight bead on the rear seam where I had cut the bottom plate. I received mixed results, but I did get it done. Lots of grinding ahead!

I flipped the chassis over to check the penetration of the welds. I was pleasantly surprised how well they had penetrated. I wasn't able to get this level of penetration with my last welder despite the settings.

Grinding down the welds took hours, but the welds were solid throughout and I only had to do a few touch-ups. I was able to get it fairly flat and even and felt good about it after it was done. After years of not getting anything done on this car, this felt like a big step in progress.

I used a Scotch-Brite™ Clean and Strip XT Pro Disc to remove any remaining paint, rust, undercoating, and mill scale on the bottom plate. These discs do an excellent job and remove very little metal. They are by far the best thing for removing mill scale.

I then sprayed primer over the bottom plate to keep it protected until I get to the paint prep stage. Quite a change from the rust-eaten tunnel I started with!

I also used the clean and strip disc on the area where I replaced the tunnel rails and sprayed primer over it.

Next step - welding on the frame head bottom plate.