Thread: Very Unique Bondo Problem! Paint Screwing it up?

Originally Posted by team canada

and it looks like you've got almost a half inch layer on there.

About the thickest it gets on this piece is 1/4" I've done 1/2" on my dash just fine though. But yeah I'm getting some bondo glass if I need to do some thick bondoing next time! I bet its faster to sand, too!

Originally Posted by team canada

Second, the soft spots you saw could possibly have been from simply not mixing your bondo and hardener thoroughly enough. Might be from the adhesion promotor, might not be, but that would be my guess... (but next time don't use the bondo at all at that stage).

I think i mixed them pretty good, but you're right, maybe not good enough. But the spots...I could see them before I even put the adhesion promoter on. They were kind of shiny, but they were still hard, so that is kind of odd.

Originally Posted by team canada

Then when you're ready to paint, if you're going to be using that duplicolor paint again, stick with duplicolor primer. It's always best (but not imperative) to match your paint with your primer, plus the duplicolor primer will provide a nice base to spray over anyways.

Ehh, I used that primer last time from duplicolor. It was called "Sandable filler primer," and it came out an orangish red. It was really nice and easy to sand and all. But it was laquer based. And that screwed everything up badly! So any alternatives? Or was I just doing something wrong? Because when I was using that primer I hadn't tried any adhesion promoter underneath it.

Thanks for all the great info guys!

Originally Posted by Altimat

I use PlastiKote sandable primer in black. That way if you do ever chip it its still black at least. And you get a better idea of your final appearance while you work.

Alright! Can I get it at Walmart, or a place like Autozone? Or do you get it from a specialized paint place?

I think I bought it at Autozone.

All they have is Duplicolor stuff at Autozone...but I found out my problem. And I know why my last few bondo projects have turned out fine. Bondo is porous and paint seeps in. I knew that, but never thought it would make the bondo soft. My problem was that the bulldog adhesion promoter was getting seeped in making it soft. The reason my stuff worked before was because I had already allowed a lacquer based primer seep in and then had sanded it off because it sucked. The laquer primer was still in the pores and it didnt soak stuff up after that. Aparently I need to seal the bondo and then put sandable primer over it and paint it. They have Duplicolor brand Sealing Primer. So i'm gonna get that. And then use Sandable Primer. They also have Sandable "filler" primer. Should I get that or just the sandable primer? After a few coats of that I'm gonna paint on it. I think i got all this figured out now. So just a FYI, BONDO SOAKS PAINT IN AND WILL GET TACKY AND NOT DRY.

You want a sandable "filler" primer, and you do not need a sealer. The sandable primer serves this function, and is used in this way over fillers (bondo) all the time. A filler primer will build thickness, which is what you want. Just make sure to allow sufficient time between coats. Think of primer as a thinner sprayable filler.

Ahh too late I got sandable primer, not sandable filler primer. The only difference the guy said was that it was that the filler stuff is a bit more thick. It was orange though. And that would look bad if I got a scratch, so I went with the black stuff. Yeah and the surface is really hard again! So if I have time I will sand on the paint a bit, re-bondo, primer it, and paint on it weeee

Unless you guys think the paint isn't too slick and I could just apply bondo directly on it? I bet it will adhere. Let me know! Thanks!

Don't bondo over paint. Its best if bondo is just applied over the base material.

What about bondoing over primer if I find a little dip or a mistake? I haven't done it yet, haven't had time but just wanting to know for future reference. Also, I did do a little bondoing over half paint/half bondo ( I couldn't sand it all down good, it would just get stuck in the sandpaper ), and it seems fine.