Anyone else have this problem ?

Thanks for the feedback guys! I'm gonna look into that vinyl dye stff.

I had that same problem at one point.. then I did some closer looking at my paints and realized that most of the paints come in Enamel, Acrylic, and Acrylic Enamel. Make sure that you don't have Acrylic enamels, because they just don't cure on the flexible rubbery plastic pieces. (never had any problem with the Model Masters Acrylics though)

So, you're talking about painting flexible rubbery plastic stuff, right?

If so, you could add a little bit of liquid latex to the paint, or you could use something called aerosol vinyl dye, that buzzy has used before:

I like the sound of that... hell I just bought a super glue bottle that has a brush on the cap.

Don't water them down.

I don't know if this is the answer your looking for but there is a thor custom on here by japormanji and he says that he coated a part of it with a thin layer of superglue first so that the paint would stick and then seal it after its painted.

it's been a while since I've done this sort of thing (a year). I know some figures themselves too forever to dry no matter the paint. I never primed the pouches and that so maybe if you try it on one you don't mind sacrificing it may help.

I've been using Testers, Tamiya,and Games Workshop Citadel acrylic paints. All with thining them with water and getting the same end result.

what type of paint are you using? For those water based acrylics may work better as solvent may interact with the materials and even melt them. I've had that problem on hair.