Cracks in spa shell - trying marine epoxy

[JasonGraham]

I have a 35-year-old CalSpa on my back patio, cost me $3000 in 1988. Maybe a decade ago it developed a small leak, not in the equipment section. I could pull off two other panels and pull out some sprayed-in foam but could not isolate/identify a leak area. There are about 6 to 8 small cracks in the shell, so maybe one or more of those is the cause of the leakage. The 4th side is 8 inches from the house wall, so inaccessible.

So I've been adding "Fix a Leak" 3 or 3 times a year, and it DOES work. This week I drained the spa, hand sanded the cracks, and used JB Weld Marine Epoxy in an attempt to seal those. After letting the marine epoxy set 24 hours, I added water, sodium bromide, and am observing....

[Kalisspera]

So far, so good, no leak.

However, even though I drained out 98% of the existing water that February day and tried flushing out the ""dead volume"" with fresh water, there could still be some of the hardened leak seal chemical "in place" doing its job. So more time is needed...

[MikeBrooklyn]

I had a similar issue with an older fiberglass tub on our patio that started leaking through tiny cracks near the jets. I ended up using a marine epoxy too after trying sealants that just didn't last. It held up pretty well. I was also redoing a nearby walkway at the time and got super into looking up stuff like release agent concrete for stamping—totally different project but oddly satisfying learning curve!