encountered some tough coating to remove?

RonnieH

Promoted Users
Hey guys, Got my 34 Ford coupe project getting close to paint time, but I just encountered some really hard, tough paint thats on the hood panels. Haven't run into this coating anywhere else on the body but this is some tough stuff. Looks as if it's really pretty old probably so I thought I would just sand or grind it off while doing some small body work areas on the hood panels. You can hardly scratch this stuff with a 60 grit angle grinder ! Guess its a pretty old epoxy coating ? finding some body filler or glaze work under some of it where I did a little repair work. Besides the spots that I needed to grind down to metal and work out, the rest of the hood looks really nice. Would it be advisable to, or not to, consider just scuffing it up and recoat it all with fresh epoxy when I prime the repaired spots ? Or should I try to completely strip this material off and start fresh ? The small areas that I'm repairing actually had small "spider cracks" around them where this old epoxy cracked. Thats where I found out how hard it was to grind these spots down to bare metal... Thanks for your advice..
 

crashtech

Combo Man
Sometimes paint that is tough to grind will powder right off with some high quality 80 grit on a DA. I would prefer to remove any coating with unknown age/properties.
 

Chris_Hamilton

Trying to be the best me, I can be
Ronnie I've encountered the same thing in the past. Probably the primer that you find on old stuff sometimes. Some sort of acid etch has been my guess. Most likely is not epoxy as epoxy didn't really start getting used until the mid to late 80's. And epoxy while tough is not impossible to get off.
Anyways 80 grit on the DA is what I use and takes it off. (like Crash stated). And like Crash said above, get the metal clean. Even though it's tempting to leave some, always better to get it completely free of any coatings. You can also get some of the "cookie discs" and use that for stripping. Much safer than 60 grit on the grinder. Google 3M Clean and Strip, you'll find a variety of choices.

Supergrit has good prices on stuff Check it out here:https://www.supergrit.com/products/products_3MSpecials-paintstrip

60 grit on a grinder is going to leave some nasty scratches. You'd be time ahead to switch to 80 grit on the DA. Safer and better for the metal on a now rare (and desirable) car like your 34 Ford.
 

RonnieH

Promoted Users
Wow, I put 80 grit Abralon on the DA and you would think its a buffing pad. Just polishes it . I finally put 40 grit on a 16" board and can eventually make some hash mark patterns with it.Thinking about doing this all over and coming over it with fresh epoxy. Never ran across something this tough.
 

Slofut

Promoted Users
Is it silver or black? Could be that damned mcu. Wait though..."finding some body filler or glaze work under some of it where I did a little repair work"
If you did the bodywork underneath it, then you put this coating over it correct? Can't remember?
 

RonnieH

Promoted Users
Its grey. I haven't done any work on it yet, what I meant was in grinding on the spots that need some work, I found where someone had done a little filling or glazing under it. The dented places had formed "Spyder cracks" in this stuff around the area. Just trying to get through it in a couple places that need some minor work. Has a couple golf ball size shallow dents. I am using Norton 80 grit paper discs now like Chris recommended and making a little slow- slow headway. This car came out of Canada where some one started the project and then stored it. Nothing like this stuff anywhere else on the body other than the four hood panels. Anyway, Ive got the spots I need to repair down to metal and clean, and the rest of it sanded and clean with some good hash marks all over, Thinking about coming over it now with epoxy and repairing the couple of spots and moving on. Of course two of the panels have louvers covering them, which makes for nearly impossible DA usage. I even slipped one end of them inside my blast cabinet and gave that a try. Completely impervious !! Almost like some kind of ceramic coating....
 

Slofut

Promoted Users
Yep, im very inclined to think silver Mastercoat mcu by PM Industries. They call it a primer, and it works as you describe. Virtually impossible to sand or blast off. Its actually grey and unlike any other mcu ive used. I would prob proceed as you’ve described. Do get several good coats of epoxy over it.
 

RonnieH

Promoted Users
That’s gotta be it! Cause I was trying to blast the spot that had some filler under it and the blaster was actually eating the filler out from under the coating and leaving the coating hovering above it. Toughest coating I’ve ever ran into. Some places has a little orange peel in it and it’s almost impossible to sand it out even with 80.
 
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