"I wonder how long JB weld would hold?"
Do not tempt me!
If it was summer and we only needed the thing for hot water, I'd
probably try it.
Either that, or I'd grab an old inner-tube and construct a
pressure-bandage, so to speak. It only needs to hold back 20psi. A
little rubber, a brace pushing on it, rube goldberg eat your heart out!
But knowing this area, it'd fail worse during another cold-snap and
then I'd have freezing pipes to dealk with as well.