With the sheet metal at the rear of the car nearly completed I moved forward to the front section where I need to fabricate the firewall and cowl area.
Photo #1 below: I began the firewall by cutting out the rough shape I want in some 1/4" flake board I had laying around. I then clamped this template in place, as shown in the photo, and marked the edges where I needed to trim off the excess. Note that I am going to recess the firewall behind the 1x1 firewall hoop rather than in front of it.
Photo #2: The outline of the template was transferred to 18 gauge and cut out with the air nippers. Note that the shape is different on the left side than the right. This is because the stock exhaust manifold on the passenger side exits much further to the rear of the engine than does the driver's side. At some point in the future I make a set of headers which could eliminate this problem but for the short term I'm going to stick with the stock manifolds. So I needed to shape the firewall accordingly.
Photo #3 shows the firewall clamped in place and being readied for welding. You can see in this photo where the passenger side exhaust exits.
Knowing I would have to work with some body filler on the rear deck curve and knowing that my novice status as a sheet metal welder might lead to a few hairline cracks somewhere or other among the 23 small pieces that are welded together on each side, I decided to experiment with a technique first introduced on HR.Com by KristKustoms and followed up on with some posts from Willys. While they used the technique for dashboard work, I wanted to try it for non-structural exterior body work. Instead of just using normal body filler over the deck curve I am experimenting with the use of inexpensive synthetic cloth (wal mart $1/yard bin) and resin. I am hoping this will not only provide solid bulk fill but that it will also deter any potential hairline cracks from showing through the paint. I simply mixed up the resin as directed, brushed it on the pre cut cloth pieces until they were soaked and then let it set up as usual.
Photos #1 and #2 below show a couple views of the experimental cloth/resin application.
Photo #1 below: The driver's side deck curve is shown here after being welded and ground down. Although it may not show real well, there will still be fill required to make the curve nice and smooth. You can still feel the "high points" wherever two pieces of 18 gauge were matched up and welded together and if this section were painted as is, the peaks and valleys would jump right out at you. However, I'm pretty happy with how the rough shaping came out. It will be a pretty good base to work from. But I am VERY glad to have this particular bit of the fabrication behind me.
Photo #2 is another view of the finished curve.
Photo #3 is a closer shot of the transition area around the driver's compartment.
Photo #1 below is a shot of the final tail piece hammered in shape over the tailer hitch ball.
Photo #2 shows the tail piece tack welded in place.
Photo #3: At the top of the curve there is another tricky transition from the curve to the driver's compartment, the hoop around the back of the seats and the rear of the door. I first made a template out of heavy paper and kept nipping away at it until I had a fairly tight fit on every edge. I then traced the template outline onto 18 gauge and cut it out with my air nippers (which I used to cut almost all the sheet metal pieces). Here the transition piece is clamped in position for welding.
Photo #1 is the second piece of the compound curve being tack welded. Since this piece was still on a relatively flat portion of the curve, not much trimming was needed. This piece is just under 4" wide.
Photo #2: Now we are into some much more difficult cutting and shaping. As the slope of the curve increases the narrower each piece must be and more metal needs to be trimmed off each piece to make it fit. Most of the pieces around the curve were 2" wide. Basically the cutting and fitting is by trial and error for each individual piece as no two pieces are exactly alike because the deck curve is intentionally a non-uniform curve. This is very slow and painstaking work to try to get the pieces to butt up to each other. Also, each piece must be tack welded in place before work on the next piece can begin. It took me approximately two full days to do the driver side curve. The passenger side went slightly faster once I had a better idea what I was doing. All told, there are 23 individually shaped pieces on each side of the car. My best advice is take a very large patience pill before tackling this job.
Photo #3: At the very bottom rear corner of the curve is a very difficult transition from the curve of the quarter panel to the curve of the rolled rear pan and wrapping around the 3" radius of the deck curve. Since the curve of this transition piece is very quick, I looked around the house for a very small metal or hardwood ball (my first thought was a croquet ball). Then I stumbled on my collection of trailer hitch balls which worked quite well for this particular task.