[digital-audiophile]

I use the marineland "holdfast" epoxy. Comes in a stick, cut off how much you want.. smush it up make sure it fills in all the holes in the frag, then hold it into a good spot underwater to a rock, adding extra epoxy if needed. I then cover the frag with a small tupperware for about half an hour as the expoxy set and you are good to go.

This brand does cure white, but if you have a decent amount of carline growth in your tank, the white will be covered within a month.