J-B Weld WaterWeld, 1 Hour Cure, Epoxy Putty Stick - 2 Pack, Off-White (8277-2)

I got this Waterweld to plug some tiny holes in a concrete drinking water cistern. The stuff works great. You need to use it correctly however. My concrete is Spaulding so if the loose gravel is not removed or sealed first, the Waterweld epoxy will incorporate the grit and not stick properly. I've used this stuff on cleaned concrete, PVC, ABS (all under water) and rubber (at the waterline) and it has held more than a year. I used it originally in summer 2023 and didn't use it all. I wrapped the remaining unmixed epoxy in plastic, used the remainder in the summer of 2024 (worked fine). Then bought another 2 pack in the summer of 24. I have more repairs to complete in summer 2025 and have one tube left. I'm sure it'll work fine when I get to the job this coming summer. If I need more, I will definitely buy this type/brand as it's served me well.

First off i do like the product, it seems to work and hold strong. I used it to cement/glue some rocks and wood together in my aquairum. After finishing it seems well put together to where i trust it with fish in the tank. But It was hard to get it to stay on the rock as it didnt want to get off my gloves that i used to apply it. That was the most difficult thing about the process and it easily stains objects like rocks, wood and potentially glass if you accidentally get it on them. I add to use some glue to add moss on the spots i used it and accidentally touched to hide it as it itself and its residue are noticeable.

turns rock solid after 24 hours if using part of make sure the rest is air tight for use later.

Normally this stuff works well and sticks to most anything. Did not work on my Fiberglass water tank the developed a leak. Sanded the spot. Cleaned with MEK.. applied JBWeld and 24 hours later filled the tank and the leak re appeared.

A very useful product for filling those knicks and scratches on boat undersides. However kneeding the putty to properly release the curing catalyst is messy and if not done right you won't have a solid repair. I found extended time kneeding the putty sends it into a rapid curing mode making filling a void challenging but not kneeding the putty sufficiently substantially extends curing time or even improper curing leaving a soft repair.