Plastic filler before of after?

[phasemaster1]

Alright need input, is it ok to apply plastic filler before epoxy coating or should I apply epoxy then sand and add filler? Thanks

[dhutton]

Some will tell you one way and some will tell you the other. I prefer filler over epoxy. No need to sand if you apply the filler within the recoat window.

Don

[snappytravis]

Whatever brand paint you use, You should always get a product data sheet. P sheet from your paint jobber.

Epoxy Primer mixed 2:1 with - Custom Aerosol Products ...
www.custom-aerosol.com/pdf/PPG-DPLF-epoxy-primer-product...

If you look this up it is on ppg epoxy primer. Just my personal experience I have been doing bodywork for about 25 years now and It's pretty dry climate in Wyoming. I did my bodywork on my Camaro then use dp epoxy primer and let set for a day or so. Then I went back with k38 then blocked and reprimed.
Your dp gives you adhesion and corrosion protection. If you are in a humid climate where it will start to rust right after the panel has been stripped bare. Then you probably should use epoxy right away. Then do your filler work over the epoxy. There is a window to topcoat of 5 days. If it takes you 2 months to do your bodywork then you need to scuff all the dp epoxy before you topcoat with the high build urethane primer. Hope this helps you a little bit. 9 out of 10 times when there is a failure in paint, It is because of product knowledge. Get the P sheets and read them, don't go off what someone else says. They are not the ones that have to sand it down when it fails or buy more product. Good luck

[phasemaster1]

So far I've done filler over epoxy. I've got a couple spots to hit.

[SS PUNISHER]

I've seen enough rust under filler to know that I won't apply it over bare metal. Not on anything worth keeping anyway...

[Evldoer]

Put filler over the epoxy primer. its good to have a barrier laid down first to seal the metal. Especially if your filling over a weld seam, you need something to seal it off so the filler will not soak up moisture through any pinholes in weld seam.