Factory Five Roadster Build Part 5 - Skinning The Snake

Here's a close-up of the rear cockpit corners. The lower panel is attached to the floor panel, and then bows out over the horizontal frame bar to come back in line with the small upper corner panel. Don't be afraid to massage these corner panels. We tweaked the bends a bit, and played with the ends and how they overlap to get the best fit.

The trunk area is by far the easiest to work on since every panel is dead-flat. Again, use the tapping screw holes as a start to Cleco the panel into place, and then start drilling. The trunk floors are simple to do as well; just drop them into place and drill through the already drilled aluminum into the frame members.

After drilling about 90 percent of the panels (some aren't installed until after the body is on), we sent out all of the visible engine-compartment panels for powdercoating at Competition Coatings. The color the wife chose is called Silver Sparkle and has quite the flash to it when the sun hits it. Here we have the powdercoated panels back and temporarily in place for final fitting. We'll have a complete story on the powdercoating in a future issue.

With the firewall and foot boxes temporarily in place, we added Mr. Gasket's G-Sport brand G-Muff Titan-Lite (PN 11027, $28 per roll) sound deadening product. G-Muff comes in a 12x32-inch roll. The Titan-Lite is 40 percent lighter than its competitors and can be stretched from 40 to 100 percent of its size-great for compound surfaces. We used it throughout the aluminum installation phase of our project.

The top-most hole in the driver's foot box was originally designed for the factory wiring harness grommet, for those using the wiring harness from a donor late-model Mustang. Since we're using an aftermarket wiring harness, which is much smaller, we remembered the Seals-It firewall grommets we saw at a trade show earlier this year, and called the company for one of its firewall grommets (PN GS404-16; $27).

The grommet fits perfectly into the opening and reduces the four-inch hole down to one inch for a much smaller wiring harness.

When you're finally ready to rivet the aluminum panels, apply a small bead of silicone (more as a vibration absorber and sealant than as an adhesive). You can apply the silicone to the panel or to the frame, whichever is easier. We found a silver-colored silicone at a home-improvement store, and it blended in nicely with the aluminum panels.

Since our build is going to incorporate windshield wipers and a heater (both of which mount directly to the firewall), we felt the additional thickness of the FFMetal 0.090-inch firewall would be a wise investment at $64 shipped to our door. The FFMetal firewall is twice as thick as the original and is ready to support any bracket or device you want to attach to it. I even got the son to help out in the garage for a bit this time. (I think he just liked using the pneumatic rivet gun.)

Due to the thickness of the powdercoat and the occasional burr, a quick pass by hand with an 11/48-inch drill bit to clean the holes is sometimes necessary. Notice we staggered the rivets on the firewall to space out the rivet's area of retention (like bolt spreaders on a valve cover). This was a tip we got directly from FFR's Joe Fournier, and it worked extremely well.

As the foot boxes and other areas are completed, it's a good idea to apply a bead of silicone to all joints, and then smooth the silicone over with a wet finger, just like caulking a bathtub. The silicone seams prevent heat and water intrusion and make for a much more solid car.

The rivet mandrels end up everywhere, especially if you use a pneumatic riveter (which we highly recommend to keep repetitive stress injuries at bay), so be sure to sweep your workspace at day's end or you might end up with one of these in your daily driver's tire-or worse, your bare foot.

The passenger foot box has a rather large opening for the intrusion bar to pass through at the front of the box. You'll also see other areas where there are gaps between adjacent panels and between panels and the frame. These areas can be sealed with silicone if the gap is small enough, or a scrap of aluminum can be riveted into place or secured with silicone to seal up the openings.