There have been many discussions of blisters and barrier coats. Along with this are comments on soda blasting versus sand blasting. Some say that vinylester gelcoat doesn’t blister. Then again, something that looks like a blister can occur.
When dealing with barrier coats, some say that none is needed if you have a boat with vinylester gelcoat. Others say you still need a barrier coat to make the paint adhere to the gelcoat. Others say that a single coat of barrier coat is the way to go to act as a “tie coat” where the epoxy adheres to the gelcoat and the bottom coat adheres chemically to a still tacky barrier coat.
Our prior boat was a 1989 C34. We soda blasted to get the old hard bottom paint off because I wanted to switch to VC-17. We were surprised to find hundreds of very small blisters (approximately the