I gave up using 2-part putty/epoxy for frags about 6 years ago, but I still use it for new 'scaping and cure it in a tub. I find the putty/epoxy stuff, if played with even just a little bit, gets all over hardware as there's always some film that floats around.
I've been using only superglue gel for all these years now.
I scrub the LR with a nail/toothbrush to clear away any mulm. Then I dab the frag on a towel, put a blob of gel on the base and mash it into the rock. The I take the frag back out, add a bit more glue and put back on the rock. After holding for say 30 seconds, I let go and use my finger to mash the glue around the base into the rock. Then I watch it for about 5 mins while it's stiffening, or if need be hold it while it stiffens.
Removal is a piece of cake using a small flat-head screwdriver, even years later.
Most gels I've used need to be shaken well before use, and then hammer the cap against your palm to prime the bottle.