When I worked in France....
we had an optical setup in a vacuum chamber, we were assembling it and realized that a mirror was too big for the mount we we had- we were short on time, so we taped it in place. (This was NOT a high vacuum chamber)
We made it work....
Right now, I have tape holding a neutral density filter in place on my current laser- not ideal, but epoxy would be too permanent.... If not for tape I think the sciences would be decades behind where they are now....