Wet Painting Over Powdercoat

[johngmartin]

Questions for the wet-painters out there: Anything I need to know for wet painting OVER an existing powdercoat? Should I sand it a bit and put a layer of primer on it? Or don't do anything and just add a few coats of the new color? How many coats do you think I would need? Recommendations on good brands of paint?

Backstory: I have a friend who has a HVLP wet paint booth setup to paint guitars, but doesn't have any experience with powdercoat/bikes. I have a steel frame with a good coat of powdercoat (unchipped, no decals) that I volunteered as a guinea pig.

[8aaron8]

I'm not sure I understand what you're trying to accomplish. Are you wanting to practice painting bicycle frames?

[johngmartin]

I have an existing steel frame that was recently powdercoated but never built up. A friend just got a wet-paint booth running, but he has only been using it to paint wood (he has no experience with wet-painting over powdercoat). I was thinking about changing the color of the frame, and he offered to re-paint it for me with his wet-paint setup. I am just wondering if we can just spray right over the existing powdercoat, or if we need to sand it or prime it before spraying it...

[eBAUMANN]

You can spray over no problem, Marty/Jordan low did that to a few geekhouse frames for NAHBS last year.

[buldogge]

Just wet-sand it with some 600 to knock the gloss down and then treat the PC as primer and start your wet coat.

The only issue I could see would be existing material thickness, especially if the frame is lugged...pc is put on in greater thickness then wet paints and can often make for poorly defined shorelines.

-Mark in St. Louis

[ultraman6970]

sand... paint over but depends a lot of the color of the pc, sometimes you have to primer then apply another color to block the previous one, then paint the color you want.

[Peter P.]

I can only tell you I had a new frame delivered to me that was wet paint clearcoated over a powdercoat color.

Within weeks the clearcoat started to peel and blister. The builder took the frame back with no qualms and had his subcontractor redo the work. I never found out what the cause was.

So just be aware that a wet paint topcoat CAN fail to adhere to a powdercoat base.

[johngmartin]

Awesome stuff, thanks guys.

[mistermo]

Spectrum powdercoating in Colo Spgs does wet clear over powder. Their work is fantastic.

[8aaron8]

I would agree with one of the above comments about sanding with a very fine sandpaper 600+ to knock of some of the luster. I would also make sure that the wet paint is laid on thin because as someone said the paint build up can ruin the look of the lug work.