A few tapes are sold to go on wet surfaces or underwater: patch-and-seal tapes from Gorilla, Flex Tape and T-Rex. Gorilla’s two wet tapes and Flex Tape set similar conditions: a smooth, non-porous surface, the water pressed out, and no pressure; Gorilla adds no seams. The hanging tapes below say to apply them to a dry surface.
Tapes sold for wet surfaces
| Tape | What the maker says | Limits the maker gives | Apply at |
|---|---|---|---|
| Gorilla Waterproofing Tape (Black, Clear, White) | “patch holes, cracks, gaps and tears, even underwater” | Surfaces clean, smooth and non-porous; water pressed out; not for seams, pressure (such as garden hoses) or hanging; may not adhere to silicone | Best at room temperature |
| Crystal Clear Gorilla Tape | “can be applied to wet surfaces and also works under water” | Clean, smooth, non-porous; water rubbed out; not under pressure or on seams | 10 to 120°F, best at room temperature |
| Flex Tape | “conforms to virtually any shape and surface, even underwater” | For wet use: smooth, clean, non-porous, room temperature; “a temporary, emergency repair”; not for garden hoses or engine repairs | 20 to 120°F (FAQ and guide) |
| Flex Tape Mini Strips | “can be applied to wet surfaces and even underwater” | May resist porous, siliconized or water-repellent surfaces; “For temporary use only.” | 20 to 120°F (data sheet) |
| T-Rex Extreme Strength Waterproof and Repair Tape | “Sticks to Wet Surfaces”; sticks “even in underwater applications” | Its data sheet’s general note still says surfaces should be clean and dry | 50 to 100°F |
| T-Rex Ferociously Strong Waterproof and Repair Tape | For “wet, rough and other hard-to-stick-to surfaces”; “even works under water” | “not designed to withhold water pressure” | 0 to 130°F (page) |
| T-Rex Clear Repair Tape | “Can be applied to wet or dry surfaces” (data sheet; it adds to follow the usage instructions for wet use) | “works better on non-porous surfaces” (FAQ) | Down to below freezing, its data sheet says |
From each product’s page, data sheet or FAQ. Gorilla Waterproofing Tape was sold as Gorilla Waterproof Patch & Seal Tape; the old page now leads to the new name. Flex’s product page says to apply at room temperature for wet use, while its reference guide says hot or cold, wet or dry. T-Rex’s FAQ says its regular T-Rex Tape can go on wet surfaces but holds best applied dry.
How the makers say to do it
- Clean first. Flex says to clear grease, oil, dirt, debris and algae. Gorilla says to rub the area clean with a sponge or cloth for an underwater repair.
- Go past the hole. Gorilla says the tape should be larger than the repair and extend beyond every edge, with rounded corners, and that overlapping tape may cause leaks.
- Press the water out. Gorilla says to rub the whole tape hard, especially the edges, and hold for 2 minutes. Flex says to press firmly for 1 minute or longer and remove all water, air pockets and creases.
Tapes that need a dry surface
Hanging tapes and strips are a different job. Gorilla’s Max Strength, Invisible Hold and Multi-Purpose mounting tape pages say surfaces must be flat, clean and dry, and its Max Strength tape isn’t moisture resistant. T-Rex says its mounting tapes need surfaces clean, dry and free of moisture. Loctite Power Grab wants a clean, dry, frost-free surface and isn’t suitable for water immersion. Scotch’s indoor tapes say smooth, clean and dry. Command says to make sure the surface is dry before applying its strips.
T-Rex’s FAQ answers yes to wet surfaces under its mounting tape heading, but those words match its waterproof tape, and the mounting tape’s own page and data sheet say clean and dry. We list T-Rex mounting tape as needing a dry surface.
For a bathroom hook, Command says to use its Bath products, which have water-resistant strips, and that regular hooks and strips may not perform as well in humid areas. See hanging on tile.