For this DIY installment, we’re literally getting under the hood of our 1953 Chevy “Bomb” Truck. After looking at its current condition, we decided that it was necessary to address the tired, hole-tattered firewall so we decided to have it removed and replaced.
Just like many projects, we discovered that the firewall was riddled with holes and dents from past abuse and poor installs, so it was time to get things prim and proper. To do this we decided to utilize a thicker piece of 16-gauge cold-rolled sheetmetal. Prior to that, we started off by using a Miller Electric Manufacturing Company’s Spectrum 375 Xtreme plasma cutter to do the dirty work of removing the old firewall and then the Miller Multimatic 200 to burn the new firewall back together. In short, it sounds like a snap but there was more to it than meets the eye, so we’ve included some of the steps necessary to make the magic happen.
1. Using a Miller Spectrum 375 Xtreme plasma cutter, we made quick work of burning out the old firewall. As always we suggest wearing protective clothing and eyewear, and be sure to have no combustible products anywhere in the near vicinity of your working area.
2. With the firewall cut out, it was time to start creating the new firewall and inspecting the surrounding areas of the cut out area for any proof of rust or weak metal.
3. We used a wire wheel on the electric angle grinder to clean off the edges. A clean, fresh point of contact is necessary to ensure that the welds have a good bond with no impurities.
4. While holding up our fresh sheet of 16-gauge cold rolled steel sheetmetal, we marked out the shape of our firewall. This step is much easier to do with a few helping hands, so have some beers ready and call a few friends.
5. Here we are drawing the cut line a 1/2 inch in from the outer edge.
6. Using our trusty electric shears, we cut through the new 16-gauge sheet like a hot knife through butter.
7. Using Miller’s Multimatic 200 with the MIG gun attachment, we made short work of welding the new panel. And for those wondering, the Multimac plugs into a 110V power supply and not a 210.
8. All welded up solid and looking great. We welded it one tack at a time every inch or so to minimize warping.
9. Using an electric grinder (and a 36-grit flap disc) we conservatively smoothed out the welds.
10. Our Harbor Freight mini DA pneumatic sander and an 80-grit disc was just the ticket for doing the final finish detail work on the weld seam.
11. Complete! With the new firewall freshly installed, the engine bay takes on a whole new life and the difference is huge.
Part 2: A Fresh Metal Headliner
Typically on Chevy trucks produced from 1947-1955 they require a separate upholstered headliner piece to be installed in order to cover up the inside of the roof skin. This panel attaches to the inner skin of the back of the cab—as well as to the edges of the roof—so we decided that in lieu of having an upholstered panel, we wanted to weld in a secondary inner roof skin that would make for a nicer, seamless, painted headliner.
For this task Brothers Truck parts supplied us with a secondary roof panel skin (PN ORPP053), but this time we used it on the interior side of the roof, instead of the outside. Since it is was made for the outside of the cab, it needed to be shrunk down some in length and width. To do this, we slit the front corners, and used our Harbor Freight English Wheel equipped with sheet rubber on the upper wheel to allow for the panel to be gradually bent in a single direction—instead of all directions creating a crown. Once the inside of our cab is all body worked and painted it’ll look custom but also natural, as if it should have come from the factory that way!
1. Our friends from Brothers Truck Parts supplied us with a new roof panel skin.
2. After taking the appropriate measurements, we trimmed the excess off of the roof panel. We also slit the front corners, and you’ll see why next.
3. Since this new roof panel skin from Brothers Trucks is normally intended as an outer piece, it was oversized for use as an inner headliner. After trimming the excess and slitting the front corners, this allowed us to use our English Wheel from Harbor Freight to roll the sides in. For this we put sheet rubber on the upper wheel so the machine would only bend the metal a single direction.
4. We rolled the edges in a couple inches on either side the panel. After a few test-fits we clamped it into place to create the final cut lines.
5. With all cuts and rolls into place, it fit like a glove and it was time to tack it in, weld, and grind. Now it’s ready for paint, and we’ll have a clean interior headliner that can be painted to match the exterior skins.
Supplies and Fabrication Provided by:
Miller Electric Manufacturing Company
Brothers Truck Parts