Paint wrinkle--how can I stop it?

I'm getting ready to paint my bike, and am doing the prep work.

Last night, I took one of my side covers (which I had previously filled and sanded to remove scratches)and painted it with a clear primer specifically made for plastics.

In the areas where my sanding had cut through a couple layers of paint, the old paint started coming up in a wrinkled pattern. I think that at some point, a PO had painted this thing with lacquer, and it is now coming up when I spray on this paint.

I had this problem previously with another bike. Then, I was preparing to take the parts to a guy who was going to paint them for me. He recommended a specific type of primer paint to use--that would be compatible with the two-part paint he would use later. Same problem--the primer lifted the previous paint. I took it to my paint guy, and he said he had something that he could spray on that would not lift the old paint, but would act as sort of a buffer between the old and new type of paint.

Does anyone know what this is, and where I can find it? I hate to think that I'm going to have to sand the whole cover down to bare plastic. Any ideas?

The stuff you're referring to is called a "sealer" - not a "primer sealer", mind you - and sometimes are water based.

Shooting rattlecan primer on the parts, eh?

What's happening is that the reducer in the enamel-based primer you're using is eating into and "lifting" the laquer.

You're shooting the primer too wet.

The common - and cheap fix for that is to shoot the initial several coats of primer DRY - WAAAAY DRY, so that it minimises the chemical interaction between the old laquer and the new primer.

But now that the old laquer has been chemically activated by the enamel reducer, it'll be tough to get it to behave itself - you can try setting the part in the sun for a day or two to allow it to re-dry as much as possible, then MIST light coats of DRY primer - read that hold the nozzle WAAAAY back - to see if you can build a layer without re-lifting the laquer.

Sealers are generally gun-based - don't know of a rattlecan-available type.

ADDENDUM: Wet sand the affected areas with #400 to feather back the lifted/rough spots. Let dry in the sun as long as practical - at least 1 whole day. Take your primer and holding the nozzle back at least 8-10 inches, VERY lightly mist a single stroke of primer over ONLY the lifted/feathered areas.

Put the part down and GO AWAY for at least an hour.

If the piece hasn't lifted again, apply another mist stroke and GO AWAY again.

Repeat 6 times.

Let dry overnight.

If it hasn't lifted by the next day, apply a LIGHT mist coat to the entire piece. GO AWAY.

Come back in 2 hours. If it still hasn't lifter, apply another mist coat. And you got it - GO AWAY.

Let it dry through the day - and if all's well the next morning, apply one more light coat and...

It sould be ready to sand lightly and apply paint.

Or, for all the time spent, you can just get a bucket of water and a piece of #400 wet and sand 'm down to bare plastic - probably take you less time.

Post edited by: Pterosaur, at: 2007/05/04 14:40

Thanks, P.

I will take a look at it tonight and see if I can sand the whole darn thing, I guess. :lol: :side: :silly:

Hey, not to worry...

I messed up one time, slathered a bunch of aircraft stripper on a set of sidecovers and a ducktail and meandered off to watch a football game and drink beer.

Three piles of semi-gelatinous goo, a putty knife, three days and a can of bondo later, I actually got to shoot some primer...

(sidecovers after stripper applied) :blush: