I have an issue similar to outlined in Can I mix acrylic paints into resin?
I have a bottle of natural liquid latex rubber, the kind that dries in the air. Can I add acrylic paint to make coats with colour, instead of the natural translucent with pale zombie tint?
How much should and can I use? Is there anything to know about the paint to decide if it can go in? I'm especially interested in dark steel, gunmetal and other metallic colors.
Acrylic paints, or modified acrylic paints, are often used to color latex, but not for what you want to do.
Latex is a little finicky. Many colorants will cause it to do unwanted things, like coagulate quickly into a sticky, gloppy mess, fail to dry properly, or change its characteristics. There are colorants designed specifically for latex. My understanding is that some of these are acrylic-based (basically a suspension of acrylic paint in latex with additives like ammonia to control coagulation). Some people do add acrylic paint to latex, often diluting it with a little ammonia.
A big exception to acrylic paints is metallic paints, which is your objective. Many of these cause the latex to coagulate. You would need to test the specific paint.
As a general rule, it's usually easier to color latex with pigments than liquid colorants. Also as a general rule, you don't want to adulterate the latex with too much of anything. The latex is mostly water. When it dries, there's much less volume of rubber. So the colorant will represent a much bigger proportion of the rubber mixture, and have a big effect on its characteristics. It usually isn't a good idea to add more than about 5% colorant. Fortunately, it doesn't take much colorant.
