The gouge on our fender is...
The gouge on our fender is easily seen here; what can't be seen, though, is the amount of distortion throughout the area that was filled with Bondo sometime in the past. We elected to replace the entire area with a fresh patch panel.
Some of you guys have asked about my '29 roadster, Project Potvin, and why it hasn't been featured lately in any tech stories I've done. The truth is I've been building a Hemi-powered '52 Ford F-1 pickup for the past few months, and we've been splitting stories up about my progress on it between STREET RODDER (see the Hemi story on page 192 in this month's issue) and Classic Trucks magazine. The project is coming along great, and it should only be a few more months until I can jump back on the roadster. My first plans are to convert the tube chassis from transverse springs to torsion bars, so keep your eyes on these very pages.
In the meantime, I've been tackling the sheetmetal on the F-1, which has proved to be a very tedious and time-consuming process. If you recall the sandblasting story I did on the '29 (July '07 STREET RODDER), you'll remember how I tried to remove the old paint and body filler on the car myself, got frustrated, and ended up getting the entire kit and caboodle sandblasted. Well, here we are again, roughly a year later, and I still haven't learned a thing.
This gauge from Miller was...
This gauge from Miller was used to measure the thickness of the fender, so the patch panel could be made from the same gauge sheetmetal. Eighteen-gauge is typical for most body panels, such as hoods, doorskins, fenders, and the like.
The entire truck was covered in three coats of paint and, in some cases, up to 1/4-inch of body filler, of which I decided I could sand off myself and save the trouble of taking it all to the 'blaster. The good news is, most of the sheetmetal has been sanded down to bare metal and actually wasn't all that laborious. The bad news is, some of the steel is worse than I thought.
All four fenders need at least one, and in some cases two, major patch panels, as well as a fair amount of hammer and dolly work. That will all be followed by a skim of body filler and then a fill primer. For now, I decided it made the most sense to start with the front fenders and work our way back, that way we could hang all the front sheetmetal if need be to finish fabricating the inner fender panels, and the like.
The damaged area that needs replacing first is the upper side of the passenger front fender, where it looks like it had a slight run in with something that created a gouge down the side. For the most part, the area could have been skimmed with filler and fixed; unfortunately, the sheetmetal was extremely thin, due to fatigue and stress to the area, and started to split when a hammer and dolly was taken to it. With that, it was decided to replace the entire damaged area with a new piece of steel.
We measured the damaged area...
We measured the damaged area and made a patch panel the corresponding size out of 18-gauge sheetmetal.
The shape of the patch panel...
The shape of the patch panel was then transferred onto the fender with a Sharpie. At this point, you can see the area that will be repaired.
Cutting away the damaged area...
Cutting away the damaged area of the fender can be done in a number of ways. A plasma cutter would work great, but there is a support bracket behind the fender surface that we didn't want to damage, so a 3-inch cut-off wheel was used.
The patch panel could now...
The patch panel could now be trimmed to fit with the damaged section removed. A pair of third-hand magnets held the panel in place while the spots that needed trimming were marked.
Once the patch panel was trimmed...
Once the patch panel was trimmed to fit, the edges were deburred, both on the fender and the patch itself, and final fit was then possible.
We put a little shape into...
We put a little shape into our patch panel before we started tacking it into place, but it was still necessary to hammer-and-dolly a few spots to keep the surfaces aligned.
A pair of Intergrips was used...
A pair of Intergrips was used on one side where the two surfaces didn't align.
These miniature clamps align...
These miniature clamps align two panels, edge to edge and surface to surface, leaving a 0.040-inch gap for full weld penetration.
A pair of Intergrips ensured...
A pair of Intergrips ensured the panels remained aligned, while a magnetic copper welding backer prevented weld burn-through by providing a backing surface to which welding material will not stick.