Mod Podge can be painted on glass with acrylics. Decoupage can be made with Mod podge, a versatile substance. All in one glue, finish, and sealer, this medium is perfect for all your projects. A clear protective coating can be left behind by using it over glass.
Paints such as acrylic, tempera, and other types of paint cannot be sealed with hairspray, which is why they are not suitable for use on rocks. Paint and hairspray react badly to each other, and some formulations of hairspray may cause your paint to melt or become gooey.