Ooops, being out of the forums lately; Thanks for the specialist title.
My first block had parts bonded together with quick epoxy, and it leaked at about 6 months of use. Each brand is different and I have no experience with araldite and water, but beware that being "water resistant" is not the same as "safe for continuous inmersion"
There is an easy test you can make: take two scrap pieces of cured epoxy, and leave one under water in a closed container. Degradation is slow, but you can have a hint in about a week; if there's some color difference between the parts means bad news. If after a month both look the same in color and hardness, you're safe
