Ecomike; Thanks for the link.., but I considered it a soap box sales tripe for home owners, i.e., painting with it for one's furniture.., NOT for ocean going boats. I do appreciate the fact that that company offers mixtures, (recipes) appropriate for many other applications. Their so-called "Seal Once Marine" coating is more for a canoe in a pond.., not in the real world where one's life is dependent on any coating that can be minimally maintained, and actually work.
Anyone serious in obtaining real fresh epoxy would avoid any far-flung middle man, or company due to the fact that liquid epoxy, and hardeners have only a storage half-life around 2.5 years, plus, or minus depending on one's geographical location, and/or storage techniques, blah, blah. "West System"-epoxies, for example, ships to one facility in the Pacific North West where anyone can obtain it, i.e., a regional pipeline dispensing out to wholesale, retail purposes. Not sure where System Three epoxies have regional outlets. Often people sell epoxy for cheap, but I doubt they are fresh.
My long winded explanations as per the poly, and epoxy glues allowing water seepage through them still stands. They, again, are not waterproof. Close, but no cigar. For the hobby folks, ok. Sort of like diver's watches.., some are water proof, but only to certain depths, i.e., 100 meters, 300 meters, and so on between sea level downwards. Some watches are only water-resistant, and may are not at all, blah, blah. However take that 300 meter water proof watch down to 301 meters.., lol, all bets are off as the seal will fail. Yes this is comparing apples to oranges, but they have one thing in common, i.e., a fail point.
My Quote--> "...However when shown that other members here have had some experiences with automatic transmission bands/epoxy/metal having a "deterioration" failure rate.., of some sort..."
The above quote goes a long way to entertain the causal thoughts found by other members recalling the deterioration of layered parts failing once water intrudes said.., of this topic.
Like marine plywood finally rotting away through either epoxy, and to a higher faster degree by poly glues, (the latter of which separation is the result), the awareness you have specifically shared, (and others have hit upon), is that some non epoxy parts will expand, and the epoxy will no longer be functional in it's combination with those other dis-similar parts, i.e., the intended integrity fails.
Really enjoy digging into a subject, and appreciate your hours of research. I am glad that this site is around so that we might better maintain our XJ's.