How do I apply a finish to as well as paint plaster?

I made a large sculpture out of styrofoam, which was then covered in some kind of plaster. I would like to paint it. I'm not sure exactly what kind of plaster it is, but it's white, and powdery, and you could chip off little dried pieces that can be crunched up into powder, but it's not weak, like it's on a pretty tall, thin sculpture and it hasn't cracked or anything after transport and sitting in a garage for months. I think I would have to apply some sort of sealant, or finish in order to paint it properly, but I have no idea!
Also if you are going to reference some sort of resin that I should use please tell me common brands or whatever so it would be easy for me to find at say, home depot or wherever

Burf7 years ago
Give it several coats of either clear acrylic or clear polyurethane paint. Once it has completely cured, you can paint over the clear coat with any compatible paint.

This will not do much to improve the strength of the plaster but it will give you a nice base to paint over.
l8nite7 years ago
It really depends on the look your going for, most plasters will take a stain or craft paints, you may need to do a couple of coats to get a rich color. Id recommend doing a test piece though
jtobako7 years ago
You can probably treat it exactly like a new wall-a layer of primer and then the base coat of paint or just plan on using two coats of base color paint.