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.

This was so easy to use and worked really well! I am not even close to being a plumber, but this sealed my leak up. Used on old copper pipe in my basement. Drying/curing time was fast and the leak stopped almost immediately. There was enough to seal around my pipe with some left over. Not sure it would be enough to do 2 full fixes but a good amount.

My pool filter cracked from failing to drain it properly up at valve housing. Was told not repairable. I tried this and it worked like charm.

had a cracked thru hull fitting I needed to get through the weekend and this stuff cured underwater and held solid. kneaded up easy and set firm in about an hour like the packaging said. used it on a leaking pipe under the sink too and same result.

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.