The Stovebolt Site Forums The Shop Area Paint and Body Shop Question for MARTINSR or anyone who knows..non TRUCK

My buddy was painting a motorcycle recently and ran into a little problem on some plastic pieces - let me explain....

All parts were stripped, cleaned (DX330), primed (K36) wet sanded and sealed (k36). The entire bike received the same process. This was followed by a basecoat (DCU?). Now here's part 1 of the issue - on the gas tank cap and the mirrors (plastic parts) the basecoat lifted drastically - looked like really old skin . Now that I think about it - all the bike - with the exception of the tank is plastic - but the above parts are the only ones we had issues with.

We let it set up and the next day, instead of repairing the problem my buddy shot clear over the top (2021). Part 2: the wrinkles flattened out! Still not perfect, but flat!

I'm concerned about the clear eventually reacting too - what do you think?
Is this possibly a problem like you refered to in the "rings" post? Any other ideas?

- Ryan

I believe you are supposed to add a flex agent to all plastic painted parts, just like if you were doing a bumper on a newer car.

I agree - however, this does not explain why it lifted on these parts and not the others - further - these plastic parts do not 'flex' - the fenders and ferring flex much more....

- Ryan

Armor-all on those pieces? My painter buddy hates the stuff, does weird stuff to paint even after cleaning well. Brian

that's possible (as the owner used to armorall parts of the bike) - but why did the primer stick?

- Ryan

Not adding flex agent would not cause the paint to lift. Flex agent only (MARTINSR can bakc me up on this) aids in the installation of a flexible, say bumper, to the car when it has been painted off of the vehicle. The problem with painting plastics is this: What kind of Plastic was it? There are many different types. You can just paint them all the same way with the same product. Some plastics have to be treated differently with different products. My guess is that the products you were useing reated to the plastics but that is just my guess

Good luck and Please keep us posted to what you find out.

No "contaminant" like Armoral is going to cause lifting. "Lifting" is caused by solvent getting under the substrate. My first thought is the plastic was originally primed with waterborne primer if this primer is sanded thin or thru it WILL lift. However, if you primed it with K36 that blows that idea. So, at this point, it makes no sense what so ever.

If the k36 held up, ANYTHING you put over it should as well. The K36 should be a "barrier" to the plastic to anything applied over it. So unless the K36 was somehow "soluable" because of improper mixing or something like that, that would explain it.
But other than that, I don't have anything to offer.

It has us stumpted as well!

Well - for now it's OK - the paint layed out when cleared - so good enough. But that leads to my next question -

what are the odds on the clear doing the same thing?

- Ryan