Bonding: Epoxy, adhesive of choice?

[Individual One]

Can epoxy be dissolved chemically or thermally?

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.

 

[Andreas Thaler]

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.

Thank you

 

[forest bagger]

As far as I'm informed and from own experience all two components adhesives weaken by high temperature.
The difficulty lies in the thermal resistance of the parts glued together.

 

[Individual One]

On a related topic, worth mentioning here for anyone intending to join parts using adhesives:
A common error is insufficient bondline thickness. The thing not to do is apply adhesive and then simply clamp the parts together. In the worst case all the adhesive is squeezed out, and a zero thickness bondline = zero adhesive = zero strength bond except for the squeezed out material around the perimeter. Bondline thickness can be controlled by using a filler of known particle size, laying fine wires in the interface, or machining appropriately sized features into one of the parts.