I have some of the body parts to my 46 primed with some red plain primer. Can I shoot epoxy primer over this or do I need to sand it off before the epoxy? Ed
Sand it all off! 1. You don't know if it was applied correctly, might not be adhered well, and flake off 2. You don't know what's under it....poorly done filler, rust, primer is porous and absorbs moisture, so even if it looks good, might be rust lurking under it. 3. Do you know what type of primer it is? Lacquer, acrylic enamel, alkyd? Epoxy might not like going over it! 4. Nothing better for corrosion resistance, water resistance, and adhesion, than epoxy primer, why would you want anything else sitting on your bare metal? 5. Paint is so expensive now a days, why would you want anything inferior under it?
1. I applied it and it was correct. 2. Applied over bare metal that was treated with OSPHO. 3. Acrylic enamel primer. 4. I shot this because I did not have time to mix epoxy primer and did not want flash rust. 5. That is why I'm trying to find out if I need to remove it. How many of you guys are professional painters.
Ahhhh you didn't say you did it yourself! So, if you know what it is, that makes it easier. Personally, I do epoxy (HOK EP-2) almost exclusively. No harder to mix or spray than any other primer, just a bit more clean up, as it is so sticky! If your acrylic is over a year old, and you used a hardner in it, it "might" be OK to go over it with epoxy as a sealer. You have a pretty good chance for success. I tend to be very cautious, though, and I would remove most of it just to remove ANY chance of paint failure. Even when you do things 100% correct, there are still times it fails. So removing even the smallest chance it will not work is good insurance for saving time and money. For example, I'm painting a 73 Riviera for a good friend. Going over a mix of original lacquer plus some panel repaints over the years (paint unknown). Got to go to bare for me to be at ease....the Pearl White paint I just bought cost about 1400$. Don't want to eat it if there is a problem! But a little time with a DA and some 80 grit will remove that old primer. I wouldn't worry about removing every spec of it, though, as I would with an unknown. Good luck!
With what you said and assuming you did apply it correctly, the answer depends on the amount of moisture over time the car was exposed after priming. And that includes humidity. Take into consideration regular primer is not a moisture barrier and while it will slow it will not stop moisture from reaching the metal below. And if the moisture does reach the metal the regular primer will also hold the moisture releasing slower than if the metal were bare. So you really have to be the judge. If it has been inside the whole time in a low humidity atmosphere and never wet you might be OK by just scuffing and applying epoxy. But if you brought it to me, without stripping I would make no guarantee no matter how you told me it was stored. And yes, I am a professional painter.
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