[Mach1460]

Ive been reading old posts and doing some research on this because the 2k urethane grey primer I have from Eastwood reccomends using a self etch primer first. Well i already have my plastic filler work done over bare metal.

(yes im a new-bee, and this is my practice car, next time ill be spraying spi epoxy over the bare metal before anything but for now this is where im at so listen up)

From what ive gathered all acid etch does is "chemically" give bare metal a surface for primer or paint to bite on to. Some posts/sites ive read say just sand the bare metal to 180-220 grit and it will have plenty for the 2k urethane grey primer to bite on to.

I have also read that acid etch is not a good idea over filler. Well what I have read is that acid etch is just crap period. haha

Currently my panel, which is half RageGold filler and half bare metal and is sanded to 180 grit--- Will I be ok just spraying my 2k urethane primer, block sanding, then using 2k sealer ?

Id really like to get this project back on the road , so toss me a rope everyone!

[Mach1460]

Heres a picture of what im dealing with ( just for fun cause pics make every post better)

[TucsonJay]

Acid etch primer... just like the old metal prep... does one more thing. It changes rust (iron oxide) into iron phosphate. That is just a dead gray material that will not cause any problems later... like rust might.

You should also know that rust starts on a microscopic level, so if the metal sits bare for a while I would either sand it thoroughly just before paint... or use some sort of acid neutralizer like those two products offer.

[Mach1460]

90% of what I've read about acid etch says it doesn't hold over time and will "solvent pop" even after a few years,and that's why no one uses it anymore, now every one uses epoxy.
That's why I don't want to use it.

[bighotroddin]

Most production shops would spray a 2K acid etch primer on that and then a 2K primer surfacer primer. Although the shortcut is to use a spray bomb acid primer or the direct to metal primer. Both of these can be subsituted if the reapir is about small like a door ding but for something like you are doing I would not recommend it.

What Tuscon Jay is is true.

For reference you cannot use acid acid etch over epoxy.

After block sanding if you have any areas that are high with metal or filler showing either spot prime those areas or if it is good just spray a coat of sealer before the color coat.

[Mach1460]

So I can spray a 2k acid etch over plastic filler? My main question is can I spray 2k urethane primer over bare metal that its sanded to 180 grit? I believe all the facts that tuscon said but it was not quite what I was looking for.

[bighotroddin]

It isn't going to hurt spraying acid etch over the filler.

I would never just spray 2K surfacer primer over metal. Really need some corossion protection and something to bite in.

[Mach1460]

Thanks for the replies, turns out on the tech sheet it says its ok to spray over filler. I missed that when I first read through it. I guess it pays to pay attention