Body Filler on bare metal, or on Epoxy?

[Donny]

Folks, I have the definitive answer! After many years of media blasting tons of stuff, and seeing tons of Bondo, I can confidently state that body filler on bare metal WILL allow rust to build up UNDER the said filler.

So, after you blast your stuff, or get it blasted, get it in Epoxy primer, THEN do the bodywork. The people that say it's ok to do it on bare metal are never around some yrs later when the rust IS under the body filler.

 

[khryslerkid]

I've seen the rust under old bondo too but what kind of adhesion do you have over epoxy sealer? Would you scuff it first, would there be a "window"?

 

[Hemirunner]

So, once blasted, shoot the epoxy primer, then do bodywork. Once bodywork is done do you cover it with more epoxy primer or do you switch to some other build up primer?

 

[flypaper]

I use ppg Wax and grease remover to remove
Blasting residue then i epoxy prime..

 

[Donny]

I don't claim to be a 'Bodyman', there's enough of them out there, and they all have wildly different opinions, and none of them do Media Blasting on a consistant basis. I would think Epoxy down on bare metal, then bodywork, then more epoxy is good as a sealer before final paint. Epoxy once dried and cured in about 48 hrs is locked down tight! You will have to scuff it up to get filler to adhere, don't use Etch as body filler won't stick to etch primer.

 

[Michael789]

Agreed Donny ,you're 100 % correct on bondo on bare metal epoxy is the way to go than body work on top. Has anyone ever used the all metal method instead of straight out bondo?

 

[747mopar]

Thanks for posting your findings, this is something I've been giving allot of thought to lately since I've noticed little freckles in my paint after 2 years. The imperfections are isolated to certain areas that just so happen to be areas that required the most work meaning the filler had more exposure to humidity. I've thought about trying to fix it but I think the only way to fix it right is strip it to bare metal, it's only noticeable under the garage lights so I'm going to run it until it's ugly then redo the whole car. Lesson learned hard is one not forgotten.

 

[Speedbird]

But, but, but.
How can one know that the metal wasn't rusty before the plastic filler was applied?
I've always put the filler over paint. But I've started doing it the other way.
Now I'm all confused.

 

[pturner]

Before or After

Donny, I am using All Metal filler on bare metal anywhere filler could contact water from the backside. All Metal claims to not like or take on water or moisture as normal filler does. Then I Epoxy, then Rage filler. I have done it this way for a number of years with no complaints.
Would like to hear others info on this thread.
I am also blasting with soda to bare metal. Then washing with Holdtite 102 to get rid of soda and residue.
But remember I am also the person that loves metal work on cars, and never complains about parts not fitting exactly.
A little strange? I guess so.
PT in Tennessee

 

[dongei]

It's a good idea except body fillers are made of Ester resins ( poly ester, vinyl ester and so forth) and they don't adhere as well to epoxies. Would be better to use a ester resin as in fiber glassing to coat first. I have used this method on steel keels on boats and it works quite well.

 

[Donny]

Or just metal finish the area out, requiring little to no filler at all...ever! LOL

 

[j1tuck]

I work for PPG and here is there on line refinish program.
http://us.ppgrefinish.com/PPG-Refinish/Training/Training-Guides/Custom-Restoration-Guide

 

[the mississippi madman]

I work for PPG and here is there on line refinish program.
http://us.ppgrefinish.com/PPG-Refinish/Training/Training-Guides/Custom-Restoration-Guide

Work for PPG you say,
Can you get me a good price on formula 924684

 

[pturner]

j1tuck, I personally appreciate the PPG manual. it is the most complete information guide I have ever seen. it really makes me re-think some of my personal preferences.
Once again THANKS.
pt in Tennessee

 

[arveeotto]

Lots of good info on this site too.
http://www.southernpolyurethanes.com/

 

[j1tuck]

http://us.vibrancecollection.com/home.aspx