Sheetmetal Assembly and Painting Questions

PotvinV8

PotvinV8

Senior Member
So, I'm in the process of rebuilding the cowl section of a '29 Roadster and I'm curious as to how Ford assembled it and to what degree before paint.

A couple things have thrown me for a loop. Notably, the fact that the cowl panels bolt to the a-pillars but are riveted and/or spot welded to the firewall and possibly to the lower subrail extensions. My concern is when it comes time to paint, how is the sheetmetal between the cowl panel and a-pillar painted? I understand this seam receives a length of welting that runs from one side of the lower cowl to the other, across the top of the gas tank in between it and the lower windshield frame. Just curious to hear how others have tackled this area before I weld anything into place and can't go back.

If nothing else, I plan to shoot some weld-through primer on any surface the will get "closed up" in the process. Thoughts?
 
Ford painted the finish color after assembly with the cowl welting installed, so the welting was body color. But you raise a good point about getting some paint on welded/bolted surfaces that will not be exposed during the final finish coat. I don't know what Ford did, but I would at least get some primer on those covered areas before welding/bolting everything together.
 
In one of the recently posted Ford model A film manufacturing montages, there is a snippet of the fuel tank already mated to the front lower cowl sections and firewall being installed to the A pillar assembly. This allowed for a quick installation of a major subassembly of the basic model A body planform. This assembly is interchangeable to all model A body types and was likely one of the last things to complete a body in white assembly before it went into the paint process.
https://www.youtube.com/watch?v=NJCh6cJB27k

The welting is illustrated in the body assembly process for the cowl. The welting was made from pyroxylin coated cloth which is basically a lacquer impregnated cloth. It acted as an anti-squeek and was the only protection against corrosion between the two sub-sections of the body. The welting is a strip of cloth that is folded over a welt cord and then sewn right up against the cord. This makes for two layers of cloth in the joint. It actually worked fairly well for a lot of models A cars well up into the 60s & 70s depending on the climate region the cars were in. It certainly wouldn't hurt to coat the faying surfaces before assembly.
 
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I paint around the edges first then install the cowl to the pillars. The areas that are spot welded to the firewall I use "Weld-through" primer on the bare metal. a step up from what the factory did.
 
Tinbasher said:
I paint around the edges first then install the cowl to the pillars. The areas that are spot welded to the firewall I use "Weld-through" primer on the bare metal. a step up from what the factory did.
Click to expand...

this is a good idea.
weld through primer is bought in an aerosol rattle can. it is a good thing to have on hand during a restoration.
any panels that are attached together by welding should get a dusting of it.
it acts like a sacrificial coating to discourage rust between the welded panels in areas that are hard to get paint into.
note!
do not use weld through primer on parts that are exposed and can be properly primed it has low adhesion propertied.
 
Thanks for the info! I've been using weld-through primer on the subrails as I've been installing them, great idea.
 
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