Tank sealer - new over old?

[Nick]

Anyone ever use new tank sealer over old tank sealer?

['Ol Scrambler]

Not a good idea to try coating over old tank sealer, this would surely result in poor adhesion of the new coating. The method I have used is to pour a strong paint remover containing Methylene Chloride (if you can still find one), or you might try KBS Coatings "KBS Strip". You will need enough to coat the inside of the tank completely and roll the tank frequently to keep all surfaces coated. Being patient and allowing time to loosen the old coating will give the best result. After an hour or so, circulating a chain inside the tank will help lifting the coating away from the surface. The softened coating may come off in pieces that you can extract with long needle nose pliers or another suitable tool. Once you have removed the old coating, cleaning the residue by sloshing some Acetone around inside may be a good idea.