My Beetle Restoration

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.

The frame head bottom plate I am using for replacement is a Klokkerholm panel made to fit 1956-1965 Beetles. It is very different than the one on my car originally, but this is really the only available option. I purchased two donor frame head assemblies, and both the bottom plates were two rust-damaged to use. These are also very difficult to remove from donor pieces because of all the seam welds. The best option for me is to use this generic one and make it work. There are huge gaps in several places like where it fits over the end of the tunnel and where it fits against the front axel mounting plate.

There is a 2-milimeter gap under the replacement plate between it and the tunnel rails. I decided to make spacers and weld them to the plate, so I removed the EDP protective coating sprayed on by the manufacturer and sprayed U-POL Weld #2 Copper Weld Through Primer on the areas to be welded.

I made the spacers and both spot-welded them to the bottom plate and seam welded them. It is overkill, for sure, but I want to have them firmly attached to the plate. After grinding down the welds, I sprayed them with the weld-through primer as well. I also sprayed weld-through primer on the end of the tunnel bottom plate where it will be welded to the frame head bottom plate.

The last steps before welding the plate on was to drill holes for the areas to be spot welded and to remove the primer on the outside of the frame head.

The replacement was initially bowed and didn't fit flat against the tunnel and was even more bowed after welding on the spacers. To flatten it and pull it down to the tunnel, I used some 2 x 4's and clamps. With this and some adjustable metal clamps I was able to get a close fit.

I started with the spot welds. I was somewhat successful and didn't make too much of a mess of them.

I flipped the chassis over and welded the areas where the bottom plate fits against the axel mounting plate and the tunnel bottom plate. These were all seam welds. My welding turned out messy, but I was able to get good coverage and penetration.

I first ground down the spot welds. Not a hard job but it took a while.

The seam welds on the bottom took hours to grind down due to my lack of welding skills. Lots of shaping and metal sculpting was required. In the end, I had acceptable results.

I re-welded the seam weld where the frame head bottom plate is attached to the tunnel bottom plate. The straight weld just didn't turn out very well and a bead weld should be a better weld visually and structurally. I will not ground this down very much as it will be covered with seam sealer and is fairly flat already.

The next step is fitting and welding the Napoleon hat!