This afternoon, I began the repair of the floor pan. This will be the largest structural and physical repair on the car that I do myself. I wanted to get the battery box done first because it needs to be solid to mount the car on the rotisserie for bottom work or for transport, and now that is done, so I am more or less out of excuses for waiting any longer. The quicker I can get the floor and longitudinals done, the sooner I can get the car in Frank Gibson's hands for the rest of the bodywork and paint.
Before I cut any metal, I made sure to review the articles by Ron Roland in the "Nuts and Bolts" column of 356 Registry, spanning volumes 15 and 16. There is extensive review of the floor pan and longitudinal replacement process, with diagrams. If you don't have these volumes of the registry, there is a slightly more concise version of all the articles summarized in the 356 Porsche: Technical and Restoration Guide vol. 1, published by The 356 Registry.
The articles make it clear that you shouldn't attempt to cut out everything at once. Rather, you should cut out the minimum amount of metal necessary to work on a particular section. Even though the remaining metal is rusty or even has holes in it, it contributes to the structural integrity of the car. Especially on open cars like cabriolets or speedsters. Ron heavily suggests leaving the doors on through the entire process to make sure gaps remain correct between the door and the body. I have to go get my doors from Frank to put them back on the body to do this. However, Ron also makes the point that coupes are much harder to bend or twist because of the roof, so I'm not as worried as I would be if this were a convertible.
Before the replacement floor can be welded in, the flanges on all sides of the car body that the floor sits on must be repaired. In my case, some of these flanges are pretty rusty as much as several inches up the side of the car. Especially in the front. Ron anticipates this, and so do the reproduction parts vendors; they supply 90 degree 18-20 gauge angle iron to weld to these sections to form a secure mounting area.
Before removing anything, I made careful measurements on the positioning of both the pedal board mounts and the seat mounts, so they can be put in the proper place when the new floor is in. I started by removing what was left of the front driver's side floor panel section. There was already a huge hole, so this wasn't so bad.
I used my air powered reciprocating body saw and cut-off tool, it took only 15-20 minutes. Then, I ground off the primer on the front left inner longitudinal, going as high up the side as I had to in order to find good metal. After this, I drew a line demarcating my cut point, and started removing the lower edge and flange of the inner longitudinal. This revealed the nasty outer longitudinal behind it. No surpises here, I knew this metal was pretty much the worst section of the car before we started any of this.
Tomorrow I will continue removing the lower section of the driver's side inner longitudinal, and then maybe even get to replacing it. The replacement metal will be scribed along the cut line, cut to fit, and then butt-welded and ground smooth.
