Epoxy is not one thing, but my experience has been that with appropriate chemistry any epoxy system can be dissolved, or at least the polymer portion of it can be destroyed leaving the fillers behind. Care would have to be taken to avoid damage to the substrate. Similarly, all epoxies can be failed via heat, it is just a matter of how much and will it affect whatever the epoxy is bonded to. Epoxies encountered in photographic equipment or sourced from a hardware store are likely to be quite low performance but serious heat resistant epoxies that I have worked with can withstand over 300C before failing. The least harmful method of detaching epoxy may be cryogenic cycling, which exploits the CTE difference between epoxy and substrates.