Basic bodywork question

I may be opening a can of worms by asking...but I have been told serveral ways to do this and I want to get some opions.

I have some fenders that I need to do a little filler work on. They are bare steel now. Should the filler be applied to bare steel, or would it be better is a primer or etch was applied first? Or, is it more a personal preferance?

 

You can buy sealer that seals the metal and then do the body work right over the top of it.

 

Here's my nickels worth:

1. Clean and sand bare metal - 180 overall and 40-80 in areas where you know you need filler.

2. Prime with Epoxy primer.

3. Fill areas that require it.

4. 2-4 coats of good fill primer overall.

Most refinish companies recommend epoxy primer under filler. Never apply filler over etch primer.

If the epoxy primer sits for too long (over a week) it should be scuffed before any thing goes over it.

Good luck.

 

Ditto what Jake said.
I had my A Sedan blasted and the blaster coated it with epoxy then I brought it home, for filler work.

 

Epoxy is definitely the way to go (under the filler.)
Just be aware that you have to wait 24hrs. with most before filler is applied.Otherwise, it can shrink under the filler.

 

Filler goes over bare steel. Make sure there is no rust or holes behind and it will last.

 

I put my filler on bare steel that has been sanded with 180. My 2 cents worth.

 

The great debate is if you epoxy prime, and then work your filler within the "cure window," you are going to scrub off primer as you sand and work the high spots, and re-wipe. You'll still have areas under the filler in bare metal, if that's what you are worried about. When blasting an entire car, it's better to get some kind of coating on it to stop flash rusting, and they say you can do filler work over epoxy primer but a small repair area that you are sanding to bare metal and working, priming is not really as important unless you are going to let the open areas sit for any length of time.

Personally, for me, if it's clean prepped metal, the filler bonds to it, and as you do your paint work everything underneath is sealed. But you ask ten cooks how to make soup, you'll get ten answers... Good luck.

 

would you sand or scuff the primer before applying filler over it?
David

 

I can't get it to copy and paste, but go here:

http://www.evercoat.com/faq.aspx

Evercoats FAQ says either way is good. Big thing is clean and get it covered.

 

Personally, I put filler over bare steel. Epoxy primer doesn't feather edge very well, and once you're done blocking it, you've taken all the epoxy off of the surrounding steel anyway.

 

Only if it has set too long, but it won't hurt as long as it has cured.

 

Many different opinions. I have had filler over epoxy sealer for the past five years and have had no sign of any problems.I to researched the question of filler over epoxy. Follow your filler and paint manufacturers application sheet. I know for sure evercoat rage works over epoxy, I had talked to them on the phone. Let your paint cure ( I let mine cure for 7 days) and scuff before filler app.

 

its more of a personal preferance if you as me. I like to do it over bare metal . never had a problem.<!-- / message --><!-- sig -->

 

I don't do much body work anymore. But when I do, I mud over bare metal.

Stay thirsty my friend....

 

By the way, when necessary, I thin filler with fiberglass resin. Try it.

 

40 years in the trade, and I've never seen epoxy used under filler in a body shop. Haven't ever seen a filler failure that I could in any way link to lack of epoxy. I did see a demo using epoxy a few years back. The filler pealed back off the edges when the guy sanded it.

 

Thanks guys, pretty 50/50 on answers. I've always done it over bare prepped steel, but I had a couple guys say it's best over primer. Just got me thinking (a bad thing)

 

It's a way of "replacing " the galvanneal coating on modern sheet metal if you grind aggressively. Over time people have gotten the idea that it improves adhesion, and that it's the "correct way". Pretty much a myth, but you know how that goes. I call it an expensive and time consuming "fix" for a nonexistent problem.

 

I prefer using it over metal. I think you get a stronger bond that way.

 

Old school over bare metal; new school over self etching and epoxy primer. Both work, my .02.

 

my '50 has bondo from the early '60s applied directly to bare steel and is still solidly on the body. See avatar fender and front door

 

Both work, but most companies that make the filler recomend filler over the primer.

 

Absolutely to go epoxy primer sealer and then body filler. Filler has liquid in it and since you could maybe seal in moisture go with sealer first, always worked for me and no problems....

 

the only time i put filler over epoxy is when i do sail panels, rockers, and windshield pillars and anything else that is leaded from the factory. i just etch prime my bare metal, grind for body work. when bodywork is feathered, clean, then scuff entire panel with 220 grit dry and red scratch pad, re-etch, let flash, then 2 part prime. 2 coats on bodywork, then 2 coats on entire panel.

 

you can go either way. I know this is a shocking suggestion, but read the directions on the filler you're using. I generally find that following the directions works for this type of stuff.

 

If the bare metal is rust free you will need to grind , sandblast the area's you want to put filler in as it needs to have something to grip onto The Bearded I Kustoms

 

I have 25 yrs. in the trade, I have never seen it either. I have only put it over bare metal. Proper prep work is essential.

 

I have done it both ways, and if done right it will last for years either way. Just make sure it is clean no matter which way you do it and it will last.--TV

 

X2......My experience exactly.