I know there are a ton of paint experts and some powder coat guys here... so here's a question for you. On our Bonneville car... we want to powder coat the roll cage, and inside the frame rails and belly pan and even under the frame/belly pan (they are one piece). Here's an early construction pic where you can see the frame rails and belly pan that is welded to the frame rails: But the frame rails are exposed, and we want those to be body color. We will have to do a little bondo work on them to make them perfect... then prime, paint etc... Way 1) We would have EVERYTHING powder coated... and then scuff the powder coat up on the exposed frame rails... lay some mud down, block that, cover it with primer... block sand, prime... block sand, prime... etc... then paint. Will this work? Or Way 2) Should I have the powder coaters put some of that tape stuff on the outer rails so we have bare metal there to paint to? Or... Way 3) Should I have it all powder coated, then strip the powder coat off where we want paint? If we do it Way 2) or Way 3).... we can have a tape line were it won't be visable... but is there any problem with the paint being partially over the powder coat? Your help is muiappreciated! Sam
Im no expert but i dont see any reason why you couldnt paint over powder coat as long as it was prepped sufficiently.
Way 1) We would have EVERYTHING powder coated... and then scuff the powder coat up on the exposed frame rails... lay some mud down, block that, cover it with primer... block sand, prime... block sand, prime... etc... then paint yes you can paint and do body work over powder coat.
Sometimes powder can have good cohesion but poor adhesion, which is to say a hard shell that remains (for a while) unbroken but does not stick to the metal underneath. I'd suggest getting friendly with your powder coater if you can, and asking them to be particularly fussy about the degreasing and baking steps of the operation.
I did my roadster the way you described in #1 about eight years ago and everything is still doing fine. Nothing special, just scuffed the powder coating well and sprayed the primer, blocked, then shot the base coat, and then the clear. Nothing to it.....
the local shop here offers a powdercoat 'primer' type finish that i believe is designed for what you want to do Sam. i would check with some of the shops in your area, has to be something like that availible up there.
we use what we use everyday.... regular ol' body filler. Evercoat Z-Grip or Rage. scuff the powder coat with 80 for deep dents finish off with 150. i like to go to 220. OR scuff it with 150 for putty and finish with 220 then a high build primer. block it, seal it and shoot it. Ricky---- is right too there is a powder coat primer as well.
Just remember you can't sand/grind/cover (bondo) ANY welds ANYWHERE on the chassis. ALL welds have to show in their original condition.
If the powder is nice you can spray it down with solvent, let it flash out, spray an adhesion promoter like Bulldog, then paint it. You'll see an extended dry time in the order of 24-36hrs before the paint is fully hardened. The result? You'll need a very sharp object to chip it off. Did this on a set of wheels and the screwdriver for hubcap removal didn't even effect the paint. Why? I dunno...
you can also use a product called "All Metal" in the areas you want to smooth out, it's an aluminin based body filler and will conduct the electrical charge, I've molded a few frames for my bike customers so they can be powdercoated and this has worked for me, than do the scuff and paint like normal.
Well then how am I going to make my bird shit welds look nice? My plan was to grind all my welds down, bondo them up, and then airbrush nice TIG looking welds on all my roll cage joints after I have it powder coated. I'm a much better painter than I am a welder. Plus, after all, it's just the SCTA tech guys looking at it, it's not like I'm racing at my local drag strip where they get REAL picky. Sam
They say ya shouldn't apply filler over paint (even scuffed-up) so I don't know You might could use a polyester spot/glazing putty over the scuffed powdercoat if you're ony spreading it on paper thin.
I've painted over powder coated frames three times . I sanded it with a DA and 400 paper , did my spot putty work ,sand ,prime ,sand again and then you can do whatever paint you want . The cars I did have been on the road since '94 ,'96 , and the last one was done last year , no problems with any of them . Good luck.
I'm just fuckin' with you guys... I know how to weld. I do try to come across dumber than I am... it enables me to sneak up on the competition. Sam
We have our parts blasted and then our powder coater does a 5 step wash before coating. It's a great base coat if you want to repaint
Painting over powder coating can be done. Couple challenges include getting a good anchor so your liquid coating will adhere well. You will also want to select a coating with strong performance characteristics as liquid coatings are not as durable as powder coatings typically. You will also want to evaluate the condition of the substrate if it is in poor condition your probably better off starting a new. If you want heres a full overview of whats involved with painting over powder coating.
@SamIyam I had some rocker covers a few years back that had been powder coated yellow. It took some experimentation but I finally got paint to stick and this is what I found. I had to lightly scuff them (300 grit) then I had a rattle can of Zinc Chromate primer on the shelf. So I hit them a couple of thin coats of the primer then I was able to prime and paint them. That is what has worked for me anyway.
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