I have had some trouble gluing frags that are on rock rubble to existing live rock in my tank. Because of my aquascape I can't remove the rock, so I am working under water (with my fingers stuck together of course). I add a generous amount of the extra thick gel from BRS to the rock rubble, try to clear away the target area, and hold it tight for 30-45 seconds. It is hit or miss as to whether or not they hold. Any ideas as to what I am doing wrong?
Well, consider how cyanoacrylate cures (snagging hydroxide ions from water in the air, according to Wikipedia - IANAChemist) and obviously working with it
under water is going to be challenging. Supposedly saltwater is even "worse" for making it cure quickly. I would say practice is all you're missing. Have extra glue and debonder on hand and just keep trying.
My best was to glue the frag, then glue the spot underwater (careful not to suck water back into the glue bottle!), then jam the two glue spots (one on the frag one on the rock) together and hold
very steady for 30-45 seconds. Super glue floats, BTW, so be prepared to have a ring of superglue around your arm where the water surface was. ;-)
^^ use epoxy. It will be much better for under water work. Especially since you are going rock to rock
Curious - which brand are you using?
Generally epoxy is not very good for stickyness (aka adhesion) - at least not the Aquastik brand (which is the same as some Oatey stuff you'll find at Home Depot - both are Du Pont epoxy). Epoxy's strength is...er....strength. There may be other types of epoxy that exhibit more adhesion in the scenarios where we need it, but I haven't heard of any specifically. Where I use epoxy is to cover over or "lock in" a frag that's in a hole that's a little too big for it - sometimes after super gluing it.
Super Glue is super duper sticky, but very brittle - especially when cured in water.
Epoxy is not very sticky, but as strong as steel.
(Again there are lots of epoxy formulas, consisting of everything from liquid to solid forms....just talking about the ones I've seen (and used) most commonly available to me in hobby or home stores.)
-Matt
