Prior to painting styrene do you do anything to the styrene like applying primer or something other then the suggessted washing. At times my paint wants to separate like the surface has oil or something on it. I am brush painting using craft paints. Also sometimes the paint wants to peel off if rubbed to hard.
First off, make sure that your craft paints are either enamels, or acrylic enamels. Non enamel acrylics don’t usually adhere well to plastic.
Second, clean the surface, before you paint it. Soapy water, rubbing alcohol, water. Just make sure that there’s no skin oils, or mold release on the surface.
I have had one, and (so far) only one case of paint not sticking to piece of plastic. It was on the very edge of a piece of sheet styrene, that was part of a detail I’d built. It was the only part of the whole piece that wouldn’t hold paint. I had to put some primer onto that part, and then repaint it.
I use cheap acrylics from Wal-Mart or A.C. Moore. I never have a problem with them on styrene. They work fine on hydrocal and gypsolite, too.
I normally don’t have a problem with craft paint sticking to plastic. However, as a added measure of security, I spray the plastic with Kyrlon gray primer first.
Nick
Ive used the model masters acrylics… and had great luck with them. Like Greyrider said, make sure to use the acrylics… adn wash first.
You MUST wash and rince styrene and metal thoroughly and use lint free or powder free gloves if you have to handle the model after cleaning. Sometimes even soapy water won’t remove some silicone parting agents. I use rubbing or isopropyl alcohol after a soapy bath. Also a prime coat should be used.
Also, if you are spraying the paint, use several thin coats instead of one thick coat.
You could also hit the part with some 800 grit sandpaper to give it some tooth, that way the paint has something to stick to. I know some styrene is very smooth, and the above suggestions should do it, but if not, sandpaper can be your friend. Use something very fine though so that the sanding doesn’t show through, like 800 grit or finer.
I almost always use either a gray or red oxide spary primer, then brush paint with acrylic paints. It gives me a tight bond with the surface. It is necessary to scrape away the paint where the glue will be applied or else the joint will be weak.