Yes, Gorilla Glue is 100% waterproof.
This is because it is made with water-activated polyurethane.
Water-activated polyurethane is an industrial-strength waterproof sealant that is used to seal active leaks in all sorts of scenarios including water treatment tanks, concrete walls, manholes, tunnels and more.
When it comes into contact with moisture water-activated polyurethane expands creating a watertight seal that doesn’t break down over time when exposed to damp.
Be aware that Gorilla Glue is not great at waterproofing polypropylene (PP) or polyethylene (PE) plastics or rubber which has a lot of oil or plasticizer in it.
The reason for this is that the glue will struggle to bond effectively with those types of surfaces.
Gorilla glue works best on surfaces including metal, concrete, stone, wood, ceramic, foam, glass and more.
To use your Gorilla Glue effectively to create a tight waterproof seal follow these steps:
- Lightly dampen the surface where you are going to apply the glue with some water, this is necessary because Gorilla glue is cured (activated) with water.
- Apply a thin layer of glue on the surface. Bear in mind that the water activation will cause the glue to expand by around 3x so do not apply too much glue (however if you need to you can wipe off excess glue with a cloth within 15 minutes of the initial application).
- Clamp the items together, or use heavy objects to apply pressure, for at least an hour. Ideally, a full 24 hours is preferable.