This is a rubberized compound. I don't see why it can to be used over powder paint. crystal clear. I've used it lead jig heads. This is an outside covering for leaks .Shelf life , I've had my can for 3 years, you must seal the can as quickly as possible it dries when exposed to air. I use a small amt, in a plastic cup, and cover can and seal firmly. You need a miniscule amount to cover one blade. I use an artist brush , buy on Amazon very cheap. Discard after use. After 3 years the jig heads are fine. PS The first can I purchased I left the the top off over night .In the AM it was rubber. It's sold in all major stores. I bought a small can to seal some leaks in my roof, did a good job. Thank you for your questions. The only complaint I have is that is not a smooth finish because of the texture of the rubber.