General motors primer

[spolij]

The paint comes off easy enough but try to get the primer off. I tried everything mineral spirits, paint remover, paint thinner, even high test gasoline and a lot of sandpaper. And I'm still working on small spots.

[Bentley]

What part of the car are you working on?

[Dan LeBlanc]

When I stripped my first 62 for a bare metal repaint, a DA sander with 80 grit was about the only thing that would cut it.  Took me about 40 hours just to strip the car that had very thin, sun baked, original paint.  So, when you wonder about the cost of a paint job, there's one thing to factor in.

[MaR]

Are you talking about the brown primer?

[spolij]

Wes   part of the dash board is alumneum.

Dan   My paint was tough -66 deville - yep the sun will do that. But no problem the paint will just fall off in another 50 years or so. lol


Mar   no it's grey

[fishnjim]

Hard to tell what's what here.   The original post has no year, vehicle, etc. then someone describes a '62?
But can you tell if it's original primer or you're dealing with multi-coats or respray?

Paint systems change over time.   So if it was "E" coat*, that's dipped and baked on at factory.   I made the catalyst for that system.   Alkyd would have been earlier and would have also been baked but doesn't really dry out for about a month.   Just enough to be dry to touch and top coat on the line.   This would be what you see in pre '60s.  Most of those are red(iron) oxide.   The grey is usually silicon, zinc, and/or titanium oxide based.
The primer color changes with the top coat also.   So light gray goes under some colors, blues, greens, metallics, etc and black is used on darker or more transparent(candy).
Primers have a high solid content also, ie, more fillers, less "paint".   So that solid stuff is what clogs your D/A abrasives.   It's milled down to about < 2 microns, when it's made.   So lots of fine particulate to get off.  The dust usually, re-adheres as it comes off.   If multiple systems were on it, then they can get "sticky/smeary" if you try to cut through it all.   I'd start with a 40 grit, anything less and it'll clog faster.   
If you're doing a whole car, better to use other methods of removal.   
* - there's many generations of E coat also.   It's electrostatically applied so covers very well, also.

[spolij]

fishnjim 66 deville.