Body filler over Epoxy?

[BadaSs_Cal]

I keep looking it up and people swear by it both ways!!
It makes sense because filler would stick better to metal.. But after sanding my bedsides down there are a couple rust spots under previous filler work (they used alot!) SO epoxy under filler makes sense too to keep out moisture...


I was hoping to spray the whole thing down today, just finished welding up all the trim holes.. and slowly do my filler here and there when I have time... then put down my high build... then seal and paint

What say you guys? thanks in advance.

thanks guys.. can a mod move this for me to the proper area please.. also Im using the TCP DTM Epoxy Primer..I know not the most advanced but in my price range. thanks

[pockets]

if there was rust under the previous filler, it tells me a) they didn't remove the rust prior to doing the filler work, or b) they left the filler exposed for far too long. Or both... given that they seemed to have just slopped it on in the first place I wouldn't doubt either.

The epoxy primer that I used back in the service was more for adhesion on bare metal than anything else, and went on fairly light, unlike say a "regular" primer. It has some corrosion resistance qualities, but that wasn't it's primary purpose. Same goes for other primers. Most are not designed to protect against moisture for long periods of time. That is what the top coat is designed for.

[Longhorn Man]

I'll bet if you had posted this in the paint and body forum you'd get a lot of input.

[68gmsee]

^ Yep. I've posted in paint and body before. You don't have a lot of visitors but there's a lot of knowledge.

[leddzepp]

moved.
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[hugger6933]

I use PPG epoxy primer. The tecsheets say[the best I remember] that you can put the primer on the body filler or put filler on top of the e-primer. I have done it both ways and don't see much difference. Jim

[lilpoindexter]

I used ppg epoxy primer on bare metal, body filler on top. Next time you're in the junkyard, take a look at the cars where a chunk of bondo has fallen off, and BAM rust underneath.
That primer is nice, thick and hard.

[cableguy0]

Epoxy over bare metal. Filler sucks up water like a sponge. Filler over epoxy is fine.

[treveiger]

saving

[BadaSs_Cal]

so are you guys putting on Bondo right over epoxy that is just dry? The plan was to epoxy the whole thing... and scuff up a little at a time and do some filler here and there while time permits...then use the sealer filler over it... then seal the whole thing.. is that a good idea?

[shortbed70]

I also use filler over epoxy but make sure it has cured good then scuff enough for mud to bite too. You can't expect anything over an 1/8" to stick long anyway so do your metalwork first then epoxy and mud
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[mrhino]

I used SPI epoxy, and they highly recommend Filler over their epoxy. then spray epoxy again over filler. then 2k if needed

[BadaSs_Cal]

Originally Posted by mrhino

I used SPI epoxy, and they highly recommend Filler over their epoxy. then spray epoxy again over filler. then 2k if needed

Hey your garage is looking like mine! Great looking body work on that gate. The po used resin with duct tape over that to smooth out mine... comes off easy.. but what a nice surprise to find the CHEV letters under there.

[chas350]

In the collision market filler is usually put directly to the steel, as time/money constraints demand it. But on restorations epoxy primer is often used first, to seal moisture away from the metal, making a longer lasting repair. Epoxy has to cure usually 24 hrs before applying filler over it, but also for the best adhesion to epoxy the filler should be applied within the epoxy re-coat window while it is chemically soft enough for the filler to bond well chemically. But brands will vary and tech sheets need to be read and followed.
I recommend and use SPI brand epoxy. It sands easily, unlike most other brands.
Good luck

Go here for more info on the use of SPI products: http://www.spiuserforum.com/forum.php

And here to purchase SPI:
http://www.spiuserforum.com/forum.php

[mrhino]

Originally Posted by BadaSs_Cal

Hey your garage is looking like mine! Great looking body work on that gate. The po used resin with duct tape over that to smooth out mine... comes off easy.. but what a nice surprise to find the CHEV letters under there.

Duct tape is always one of my Favorite ways to smooth & fill.

The crap people do.

[Crabass]

Not all body fillers are the same-----some are moistureproof and some not. The most popular and well known filler (which shall remain nameless) is essentially talcum powder mixed in with polyester resin, no barrier to moisture (the "sponge" effect mentioned by Cableguy).
I have had very good results with a product called "All Metal" that is waterproof and seems to bond just about as well as epoxy (got a bit on the very slick chrome of a liftgate handle many years ago and left it to see how well it would stay.........still there completely intact even after I've tried to scrape it off with my fingernail). It cures very hard so is not easy to work, can get a bit brittle if applied too thick without some reinforcement, and is more expensive. It's all I ever use now, but I don't do much body work compared to many of the members on this forum.

One thing to keep in mind is that you have to seal the metal from ALL sides to keep moisture and O2 from doing their ugly thing!