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What kind of primer?

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
I'm having to strip the bed on my Ranchero. It will need priming, but I'm confused about all the primers I see. Self etching, sanding, epoxy, and automotive primer. Also, I'm not equipped for spraying big stuff and will likely be using aerosol cans.
 

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AC932

Contributor
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Sep 17, 2018
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247
Etching and Epoxy primer are pretty much the best choices for your first coat on bare metal.

Self Etching should only be used on bare metal, it actually chemically eats into (like using an acid wash) and bonds to it for better adhesion. Epoxy doesn't really eat into the metal, but does seal it very very effectively, and can be used over old paint.

The sand and fill and "automotive" are fine for bare metal, but their main purpose is to improve your top coat appearance. That's why they're sandable. I've had best results with these over an epoxy or etching primer, where they fill in the little defects and make your paint coat smooth. You're doing a truck bed, so I don't imagine this is a factor for you right now.

All that said, I did my bronco with the Rustoleum Sand and Fill rattle cans. Filled in all my little pinholes in the bondo and I'm not getting any more chips than I'd expect with my mileage.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
I revert back to the "check your painter supplier or painter"
Make sure all the products are compatible. Some are not and that can cause a failed paint job.
 

1970 Palmer

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Mar 2, 2020
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I revert back to the "check your painter supplier or painter"
Make sure all the products are compatible. Some are not and that can cause a failed paint job.

X2, Exactly.

Follow your product's MDS (material data sheets) for instructions.

I believe you will find that etch (the old school methods), and (today's) two part resin epoxy primers do not mix without issues.

Bare prepped surface (fiberglass/aluminum/steel), epoxy primer, any necessary filler, block sand, seal coat (just diluted primer), sand to 320/400, top coat with your choice of single stage, or BC/CC.
 

mebco09

Full Member
Joined
Aug 13, 2018
Messages
460
If you don't have the equipment to use a spay gun, I'd use one of the 2k epoxy packs.

https://www.eastwood.com/eastwood-s...MI0o6eq-2L8wIVg5qGCh0RDQfQEAAYASAAEgLPr_D_BwE


Sent from my iPhone using Tapatalk

This ^^^

Probably 2-3 cans for that truck bed. Use epoxy for sure. The other "automotive" spray primers are really just aerosol body filler in a can, and they may absorb water.

Hold onto your wallet though. I think 2K epoxy was $26 bucks a can at Wesco auto body, and hit-and-miss on availability.
 
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blubuckaroo

blubuckaroo

Grease Monkey
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Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
Ok, I have another primer Question...
If you've already got paint or epoxy primer on the surface, and you're fixing a dent, filling a hole, or other work where you're exposing the metal, can I just use a "rattle can" self etching or sandable primer on the spot before painting?
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
what ever you use to cover the body work you should seal with epoxy primer before the overcoat. as you stack different materials under the overcoat the more likely you can run into incompatibly issues. you don't want this when your spraying your final paint. Most good paint is a system from one manufacturer starting from bare metal to the final coat. as you mix and match you risk having problems that you cant cover up once it is at the final spray. epoxy primers were conceived to help with this issue as once cured the solvents in the top coat don't penetrate the barrier coat.
 
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blubuckaroo

blubuckaroo

Grease Monkey
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Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
I thought that epoxy primer was put on the body after blasting. You're saying that daily after work on that body, epoxy primer is mixed and sprayed on each small area?
 

Madgyver

Bronco Madman
Joined
Jul 30, 2001
Messages
14,678
Ok, I have another primer Question...
If you've already got paint or epoxy primer on the surface, and you're fixing a dent, filling a hole, or other work where you're exposing the metal, can I just use a "rattle can" self etching or sandable primer on the spot before painting?
yes, as long as it is etching primer. use discretion when choosing when to mix more epoxy primer. I'll do rattle can etching primer for small break throughs.
 

Madgyver

Bronco Madman
Joined
Jul 30, 2001
Messages
14,678
I thought that epoxy primer was put on the body after blasting. You're saying that daily after work on that body, epoxy primer is mixed and sprayed on each small area?
you could tint the primer surfacer with a single stage color to create a sealer coat.
 

EPB72

Contributor
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Joined
Jul 13, 2019
Messages
801
Loc.
Pleasant Hill, CA
I thought that epoxy primer was put on the body after blasting. You're saying that daily after work on that body, epoxy primer is mixed and sprayed on each small area?

YES ... epoxy after blasting...I use SPI so what i write applies to that...PPG is OK as well,,but I've heard from a few they prefer transtar epoxy over PPG

Metal work ,blast possible more metal work,,epoxy.

If your ready for any filler work apply on top of epoxy in the epoxy recoat window usually wait 24 -36 hours and upto 5-7 days after that you would have to scuff re shoot area and apply filler ,,,after sanding and happy with all filler work reshoot epoxy ..this is where you could either block sand and prime and block and prime with epoxy Or could use a 2k or high build primer and block as needed {but if you go that route don't put filler on top of 2k or high build}

once all done blocking to your liking then apply epoxy as a sealer then SS or BC/CC
 

mebco09

Full Member
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Aug 13, 2018
Messages
460
YES ... epoxy after blasting...I use SPI so what i write applies to that...PPG is OK as well,,but I've heard from a few they prefer transtar epoxy over PPG

Metal work ,blast possible more metal work,,epoxy.

If your ready for any filler work apply on top of epoxy in the epoxy recoat window usually wait 24 -36 hours and upto 5-7 days after that you would have to scuff re shoot area and apply filler ,,,after sanding and happy with all filler work reshoot epoxy ..this is where you could either block sand and prime and block and prime with epoxy Or could use a 2k or high build primer and block as needed {but if you go that route don't put filler on top of 2k or high build}

once all done blocking to your liking then apply epoxy as a sealer then SS or BC/CC

Yes to all of this, but make sure you read the product info sheet for recoat windows. Some might be as long as 5-7 days, bit others are as short as 72 hours, some might be less.

It gets tough to use modern paints and do this as a hobby. You have to schedule your work time around recoat windows, and hope other things don't come up to get in the way.

AND- you will be money ahead buying a decent primer gun and buying bulk materials. That way you don't have to pop the catalyst on a $26 can every time you need to touch up some sand through spots.
 
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