Epoxy over Ospho. Yes or no?

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DanMcG

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I got my stepside box back from the sand blasters and I had intended on wiping it down with Ospho, bang out the dents, then hit it with an epoxy primer. I've reading a lot of posts on the internet about them not being compatible with each other.
Do anyone do it this way with good results?
I'd skip the Ospro but it might be a month before I'm ready for the primer and would hate to have it flash rust.
 

4WDKC

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I got my stepside box back from the sand blasters and I had intended on wiping it down with Ospho, bang out the dents, then hit it with an epoxy primer. I've reading a lot of posts on the internet about them not being compatible with each other.
Do anyone do it this way with good results?
I'd skip the Ospro but it might be a month before I'm ready for the primer and would hate to have it flash rust.


I have a friend that always tells me not to use epoxy primer, he says etching primer gets a better bite to the metal and the primer filler/sealer will seal it.
 

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I always see guys anymore who say not to use self etch said they don't think it works or trust it. I use it in rattle cans for small things, and I have used epoxy but no long term results, I've never had anything long enough to see how it holds up later.

Honestly why not go ahead and prime and not ospho? I thought that was to treat and remove rust, not to protect from rust? If it's because of body work, I'd prime it, bang it out whenever and if need be sand and re prime, alot of guy body work right over epoxy and once done re epoxy
 

yevgenievich

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Regular primer will let moisture through without sealer and metal will rust. Epoxy on my camaro has held up fine for last 8 years. I ground off rust and most of paint and then rolled epoxy on. Kept it from rusting and sealed. Ospho supposed to be able to be followed by primer, not sure how well with epoxy. Maybe change plans to later use etching primer and sealer instead of epoxy primer
 

chengny

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I got my stepside box back from the sand blasters and I had intended on wiping it down with Ospho, bang out the dents, then hit it with an epoxy primer. I've reading a lot of posts on the internet about them not being compatible with each other.
Do anyone do it this way with good results?
I'd skip the Ospro but it might be a month before I'm ready for the primer and would hate to have it flash rust.


Ospho (phosphoric acid) is used as a rust converter, not as a rust preventative. If you get your frame back (and it's down to white metal), but you won't immediately be able to apply your final coatings for awhile, then you should get some kind of light primer coat in the interim.

I have been using a Rustoleum product called Rust Reformer for quite a few years now. While I am not generally a big fan of Rustoleum (and I don't believe Rust Reformer can actually reform rust), that particular product does work great as a rust preventative.

I like to get my parts blasted in big groups. I bring them to the local grave stone place (the lettering on the headstones is done by sandblasting) on days when work is slow - maybe nobody died. The guys in the shop are getting paid anyway, so they clean my parts up for a very reasonable price. Say like $20 for a radiator support frame and a set of rims. Almost like a flat rate for however much I bring in. The more stuff I bring in, the cheaper the cost - and they will charge me something every visit. So it is in my best interest to get these parts cleaned up in big batches.

When I get the stuff home and look at how much painting will be involved, I know that some parts will have begun oxidizing before I can coat them. Out come the rattle cans of Rust Reformer. I warm the cans in a sink full of hot water (to get a finer mist and better pressure behind the spray) and lightly coat all surfaces of each part. Doesn't take much. And, since the product is flat black, any holidays are readily apparent when applied on the freshly blasted steel. Only takes about 1/2 hour until completley dry and then I can forget about painting till I have time - and not worry about rust flash. All it takes is one humid night in the summer and that freshly blasted white metal is covered with light rust by morning.
 

DanMcG

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Maybe change plans to later use etching primer and sealer instead of epoxy primer
Thanks, I'm looking into that now.
You rolled the paint on your camaro? did it lay flat when it was all said and done?
 

rpcraft

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To be fair you can roll on the rust reformer too. It'll require less setup and still be pretty easy to apply, and if you get a good clean application it will settle some and look top notch
 

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I did zero actual body work, just rough sand and clean rust off before applying. It came out ok. It had orange peel, but was expected. Not much I could do in apartment complex parking lot.
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Thanks, I'm looking into that now.
You rolled the paint on your camaro? did it lay flat when it was all said and done?
 

rpcraft

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Pros get orange peel fairly regularly in a paint booth, I figure the difference is they don't usually get bugs and dirt as well, lol.
 

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They also get a lot more money than you did!!!LOL
 

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I don't know of any paint company that recommends etch primer over sand blast profile. These parts should be epoxied. Your best bet would be to get them back from blaster and put a couple good coats of epoxy on them as soon as possible. Then at your leisure you can poke out dents and do your body work on top of the fully cured epoxy.
 

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