From what I've read you don't scuff the epoxy.  Filler goes right over top of it.  

Michael H. wrote:

Good to know.  Do you scuff your epoxy primer?  If so, what grit do you use?

 
Yes you have to scuff it once it's past its cure time.  I like a scuff pad because epoxy doesn't sand very well.  It'll ball up on the paper.  A scuff pad works very well.

Different epoxies will have different cure times.  I've never waited to respray anything over night so I haven't pushed the limits of those cure times versus needing resanding.  With PPG epoxy you can kind of tell if it's dry enough that it needs scuffed or not.  Hard to explain.

Repainting my f150 the epoxy is fully cured before I have time to get back to it.  My garage isn't big enough to work on it and keep my mustang inside so I haven't pushed to move one out and the other in.  Making painting progress really slow on the truck.  So I have to plan out what I'm doing and how much time I need to do it.  It took me pretty a whole day to paint the hood on the truck.  Sadly I got debris in the clear.   I may two tone the hood or respray it.  It's just a daily driver but I'm not pleased with it.  Lol

Last edited by RTM (7/23/2026 3:52 PM)

TKOPerformance wrote:

RTM wrote:

Different epoxies will have different cure times. I've never waited to respray anything over night so I haven't pushed the limits of those cure times versus needing resanding. With PPG epoxy you can kind of tell if it's dry enough that it needs scuffed or not. Hard to explain.

Repainting my f150 the epoxy is fully cured before I have time to get back to it. My garage isn't big enough to work on it and keep my mustang inside so I haven't pushed to move one out and the other in. Making painting progress really slow on the truck. So I have to plan out what I'm doing and how much time I need to do it. It took me pretty a whole day to paint the hood on the truck. Sadly I got debris in the clear. I may two tone the hood or respray it. It's just a daily driver but I'm not pleased with it. Lol

Its just a DD, but that also means you'll have to look at it every day.  I get it.  
 

 
Trust me I know and the debris is on the drivers side of the hood right where it'll laugh at me.  Lol

I was thinking about the comment on applying bondo over semi fresh epoxy.  I don't think I've ever done that for fear of reactivating the epoxy.  I've always let the epoxy cure for a few days before applying any filler over it.  Now I have sprayed epoxy as a sealer right before I spray a basecoat.  If I do this I tend to thin out the epoxy to get it to lay down flatter, less orange peal.   On my truck I've sealed it after sanding all the old paint down.  As long as I don't break through the high build primer then I won't need to respray epoxy again.

I'm far from an expert.  I just feel epoxy takes longer to cure than a coat of bondo does.  I guess it would. E okay because bondo won't seal or trap anything or it shouldn’t.  I just wouldn't go to sanding the bondo right away but that's just me.  Not sure if it's right or not but has worked for me. 

By way if you ever want a nice gloss black look.   You can spray clear coat over the epoxy.   I use to spray rear axle housings like this and small parts.  It was mostly because I had several things going on and would have left over material. 

Today I finished the bondo work on my truck cab corners.  Epoxy before sanding primer. Ready for final sand and paint.