Our decision to use a brand-new Dynacorn '47-50 Chevy truck cab from Chevs of the 40's instead of a readily available vintage cab for Project Shop Truck was motivated by the challenge of creating a street rod truck entirely from aftermarket components. One of the advantages of starting with brand-new sheetmetal (aside from the personal satisfaction of eventually meeting our challenge) is that we avoid having to do a ton of metalwork. Unlike most project trucks, our steel five-window has never done a day's work in its life, has never been in a traffic accident, and has never been the victim of anyone's amateur bodywork. But that doesn't mean that there weren't any improvements to be made. As with any reproduction body, a little sheetmetal massaging will be needed before Project Shop Truck rolls into the paint booth.
Being a fairly faithful reproduction, our cab featured a hole for the fuel filler tube in the stock position on the right side of the rear of the cab. Patching that hole to clean up the lines of the cab is one of the most common modifications made to these trucks, and Jonathan Williams at Hot Rods by Dean (Phoenix) had the job done quickly.
First, it was necessary to...
First, it was necessary to remove the inside lip from the circumference of the hole using a reciprocating saw.
The ragged edge was deburred...
The ragged edge was deburred using a die grinder.
Jonathan Williams, of Hot...
Jonathan Williams, of Hot Rods by Dean, followed that by grinding the area around the hole to bare metal to prepare it for welding, removing the paint with a cleaning disc.
He used this sheetmetal gauge...
He used this sheetmetal gauge to determine the thickness of the steel. The patch should be the same thickness, or as close as possible, as the surrounding sheetmetal-in this case 20 gauge.
The cab bows out vertically...
The cab bows out vertically and horizontally at this corner. Williams fed the square piece of steel through the English wheel...
...in both directions to shape...
...in both directions to shape it into the right curve.
The circumference of the patch...
The circumference of the patch was drawn onto the sheetmetal, using the hole in the cab as a template. Notice the arrow drawn inside the circle, which will ensure that the patch gets positioned correctly.
After the circular filler...
After the circular filler patch was cut out with a pair of snips, the edge was deburred using a grinder.
The position of the hole made...
The position of the hole made it impossible to clamp the filler patch, so it was held in place with tape until a couple of tack welds could be added. The patch was ground just a hair smaller than the size of the hole, to give the weld good penetration. If the patch was too tight and unable to move slightly during welding, it could pop out of position and overlap the outer steel.
Using a hammer and dolly on...
Using a hammer and dolly on the tacks stretches the welds, which also helps keep the patch from overlapping.
This is your only chance to...
This is your only chance to see Williams' nice weld. Moving to different areas while welding keeps heat from building up in one portion and warping the metal...
...The angle grinder ground...
...The angle grinder ground down the weld.
The contour of the filler...
The contour of the filler patch has to be consistent with the surrounding metal. Williams used a hammer and dolly, along with this slapping spoon to shape the steel, feeling with his fingers to judge the job.
The larger area around the...
The larger area around the patch was cleaned up with the dual action (DA) sander.
Body filler was added to the...
Body filler was added to the area and then sanded smooth.
Williams alternated between...
Williams alternated between 80-grit sandpaper on the DA sander to knock down the material, and 120-grit on a handheld sanding pad to smooth it out.
When Williams was satisfied...
When Williams was satisfied with his work, the truck went into the paint booth where it was masked prior to being primered.
Most of the material we were...
Most of the material we were using, including the abrasives, the masking paper and tape, primer, and chemicals were from Summit Racing Equipment. Chris Walker, painter at Hot Rods by Dean, mixed the 2K Urethane Primer Surfacer and Urethane Activator according to the manufacturer's directions.
After three coats of primer,...
After three coats of primer, all that work is completely concealed and Project Shop Truck is one modification closer to being complete.