Is chalkboard paint washable?
Herein, do you need to seal chalkboard paint?
The first reason is to seal a porous surface (such as a painted chalkboard) so that you can easily erase your liquid chalk markers. A single coat should do if you are sealing over top of your chalk markers so they can't be erased. Be sure to follow the manufacturer's instructions on the spray can.
Also to know, what surfaces can you use chalkboard paint on?
Chalkboard paint can be applied like regular paint, but Radek says it should not be applied directly to plastic, bare wood, or metal without priming the surface first. Radek says that once the paint is cured, the surface should be prepared for chalk by rubbing the side of chalk over entire surface and erasing.
Optimal coverage requires two or three coats of chalkboard paint; allow each coat to dry for at least three hours before applying the next. Even after the final coat dries, allow the paint to cure for several days before writing on it with chalk.