Please help - surface imperfections coming out from underneath the primer!

Have you used Motip primer before?

Their website claims it's good for use on metal, wood, stone and some other stuff but no mention of plastic. Is it possible it is attacking/crazing the plastic?

Hello Greg!

Thanks a lot for your message. Yes, I have used Motip primer before and I know it messes with the plastic some - the way I see it it gets better adhesion this way. But on most models I don't get any problems, even on the VW it's only the two spots on the roof that give me problems. I would like to know what exactly is happening here, so that I could stop it.

Thanks again and have a nice day

Paweł

Pawel, I've come across this once or twice on a build and no amount of sanding and filling seemed to help. It wasn't as wide spread as it appears on your roof but my conclusion was that it was foreign material in the plastic itself from the factory. Only my conclusion.

Sorry my guess was wrong, Pawel.

I do hope you get this figured out, it's a mystery.

Templar has an interesting theory. Or maybe somehow melting and rehardening the sprue changed the plastic in some way to make the paint attack it even worse?

I haven't been around for quite a while, hope you don't mind the reply... I think you're going to need some type of barrier coat to keep this from coming back. Or, use paints that aren't solvent based. I'm no expert but it seems that you run across plastic or spots in plastic that do this sometimes. Sometimes just breaking the surface of a piece of styrene by sanding seems to cause this so it may have happened anyway but I suspect using the melted plastic as a filler had something to do with it. I would suggest sanding smooth, very smooth, and spraying or brushing on Future. Or whatever it's called these days. And if that's available to you. If not, then you may need to use water based acrylics. At least on that part of the kit. Tony

Hello!

Thanks for all the comments!

templar1099 - I think it definitely has to do something with the plastic under the paint, I just wish I knew more about what's happening here. And how to stop it!

Greg - no problem, if somebody asked me I'd probably start with similar asumptions.

Tony - all replies are heartly welcome here! I agree with you on the plastic. I've had a similar thing once when I took an old part, laying there for years, sanded one detail off and then tried to paint it - the contour of the old detail showed through like twenty thin layers of paint! That one finally disappeared, let's see how this one will go. I have also thought about some protective layer, but I'm afraid that Motip might at least partially get through and then we would see really bad cracking of the surface... But I'll try that one too.

Thanks again for the comments and have a nice day

Paweł

Best wishes!