I'm painting some rocks for a school project, little ones around a garden, and I'm looking for a good sealant/clearcoat. The rocks are pretty porous, but the paint is water-based, so it will easily come off.
I'm looking for a sealant/clearcoat that will work well. I'm also using the same paint markers on plastic. I sand the plastic, spray paint it white, color it, then clearcoat. I need a clearcoat that won't crack the paint like the one I had was. If there's one that would work on both surfaces, even better.
The Posca markers are water-based paint markers and the clearcoat was Rustoleum Satin Clear Enamel. I took an outlet cover, sanded it, spray painted it white, let it dry for about 20 hours, then painted it with the Poscas, let that dry for about 4 hours, and then used the clearcoat. I put a small fan on to dry, only for the clearcoat (is that maybe what made it crack?).