does anyone know who makes an acrylic paint that represents old, gray, rotted wood? I need it for an FSM kit.
Instead of using acrylic paint for that effect you might want to consider an India ink/alcohol wash. It's great for giving wood a real aged look.
Agreed. No one paint will give you rotted wood.. But if you do go paint, thin say, concrete gray way way out with water like it's ink. Apply it. Then thin way way out, say, some back, some brown and streak these over the gay, assuming the items have been scored up enough to look weak and splintery ...If it's for a plastic item, not wood or paper, it might not take too easily.
should I wait until the concrete gray is dry before I streak on the black, then wait for the black to dry before I streak on the brown?
It would probably be a good idea. Because washes are thinned, they might just blend together into a muddy mishmash of color if previous layers aren't dry. Steve S