If you need to glue on something that you might need to get under one day, what is a good glue ? Particularly for a lens type thing, my crimp tool has a plastic graduated cover that fits over a slot that shows the crimp setting. I had to pry it off (thankfully easy) because it was filled with some kind of weird fuzz underneath!.
So I am thinking what is a good glue that is slightly gummy, peelable and stable.
I feel like fucking around with epoxy or super glue is a bad idea here. Electronics silicone spread with a tooth pick?
Contact cement is the stuff most similar to the adhesive backing on self-adhesive things. It comes in many kinds. But glue is likely the wrong approach entirely.
They sell double sided tapes specifically for lens (by which I assume you mean bezels/front panels, not optical lenses) attachment. Easy to find on AliExpress.
I’ve used ordinary double-stick tape for this purpose before. You want the art/hobby kind that has a separate liner (not the office kind that peels off without a liner, like ordinary scotch tape), so that you stick it down with the liner still protecting the other sticky surface while you trim it down. Then you peel the liner off just before joining the objects.
I’d also take a look at 3M VHB tapes. They’re “double-sided” tapes that I put in quotes because it’s not so much double-sided as it is simply a layer of adhesive with no backing tape to begin with; it’s basically either clear acrylic gel or foam adhesive with a liner so it can be unrolled and applied. It works great for semipermanent applications onto smooth surfaces, with a strong hold but clean removal. It’s available in various thicknesses, you’d probably want a thin one.
Another thing, similar in concept, is the 3M “Command” adhesive strips used on self-stick hooks and whatnot. They’re quite similar to VHB, but have pull tabs: pull on the tab and the adhesive stretches and pulls away without damaging the surface. (These are what Apple now uses in their gadgets to keep the batteries from rattling around, while still making removal quick and safe, since you don’t want people digging around lipo batteries with screwdrivers or knives…)
Tesa makes equivalents to all these products, and no-name manufacturers make clones of varying quality.
Oh yeah: in all cases, you need to make sure the surfaces have been thoroughly cleaned before applying glue or tape: free of dust, free of oils, and free of water. (Wipe down with solvent.)