As I mentioned a quality butyl tape is VERY, VERY flexible. This photo represents well over 1000% elongation of the original squished thickness and this pre-EPA butyl is still stretching and much of it has not yet failed.


You will also notice that it is still perfectly adhered to the deck and the cleat and never let go of either despite its very low 10-20 PSI bond strength, when compared to some polyurethanes gelcoat destroying 700 +/- PSI adhesion.


Butyl tape also cleans up easily. Remove the fitting and clean the surface with mineral spirits and a rag. That's it!


Because butyl can be softened with mineral spirits the one place I won't use it is on fuel fills or fuel vents. If you normally clean your decks with potent solvents, doubtful, then just be careful around the butyl bedded hardware.