I bought a product today called Just for Copper. It is for joining copper pipe and fittings. Expensive ($15 for a bottle that claims it can do 40 joints, but if it does 10 I will be surprised) but it claims that it can be used on wet pipe, and should be good for places where a torch is not suitable. Hopefully it will have a better shelf life than the epoxy I have used in the past in such places.
I did up one joint (at $1.50 a joint I didn't want to experiment too much) and it seems fine. 3 posts at various groups say it is good; but I wonder if anyone has had a bad experience. I mean, one bad experience is more important to hear about then a bunch of good ones.