The Stovebolt Site Forums The Shop Area Paint and Body Shop No primer on big bolts?

I am finally getting into the bodywork on the 57 GMC 370 LCF.
I am very surprised, there is only one coat of paint, very thin now. Looks to be the original paint, never re-painted.
With just a small amount of sanding and you are to bare shiny metal. I have not found any signs of a primer coat anywhere.
Since GMC's were built for work back then, think the factory just said heck with primer??

ALL trucks were built for work, and GMCs were supposed to be the best [higher priced anyway ], there was primer from the factory, all I've seen from the TF years had a black primer coat, like EDP and quite tough, can't imagine an LCF would have been treated different

Bill

I think a lot of people expect to see a heavy layer of undercoat
supporting the finish. The EDP coat was sufficient and was all
that was used under the factory paint.
DG

You know how it is, when you start removing stuff and really getting into one. You will notice all the details. Such as someone else has redone something, bondo, wiring messed with, layers of paint, dozens of small things.......
I have not found one thing that did not look like it came from the factory. Such as the small metal covers that are screwed over the door hinges.
It's a mystery. I am not doing any sandblasting. Just water sanding by hand. When it feathers out, there is no black or any other color. It just feathers out from red to bare metal. The doorjambs or anywhere show no signs of primer.
I have done a lot of the old 2 cylinder John Deeres of the same vintage. They used a super great, yellow primer.
I just thought this was strange. Maybe the EDP is there, and I am just not seeing it?

hmmmm, faded red paint job ... maybe GMC still used the red lead kinda primer and it's just not visible as a separate layer?

Bill

You know Bill, I had the same thought. I think you are right.
One time I though I got a glimpse of something that looked like the old red oxide primer. But dismissed it.
Yes, the faded red is unbelievable thin. It only take a few strokes with wet 220 grit to get through it.

60 years ago primer was applied for something for the paint to stick to and the old red oxide primer was not very thick. Not like today's primer that is also used to cover imperfections.

Crenwedge, at least some things have gotten better. I get primer from my Son's bodyshop. It is unreal how it covers sand marks and imperfections. He uses a 3-part primer. It's a primer-reducer-hardener mix.
You can wet sand/block it once, then spray another coat and block/sand with 500 grit. Then you have a super smooth surface to paint on.
(But it is expensive stuff)

My 46 GMC had red oxide primer, so I think your 57 definitely would have had primer.

I have encountered red oxide primer on all of the 1941-42 panels that I have worked. It is often relatively thin.