Using Underwater
Yes, Flex Paste will work underwater and on wet surfaces. For best results, you may want to do some etching in order to increase adhesion. Also, you may need to apply a little extra Flex Paste when working underwater.
Here’s everything you need to know about Flex Paste
How long does it take for Flex Paste to dry?
How do I use Flex Paste 9 oz cartridges?