I've used Duro's Superglue Gel and love it. Of what I have used so far, it's been the thickest and it seems to set faster. I've had a couple of times gluing down frags and if I just put a big glob on the underside of the putty, the glue grabs the rock almost right away, so I don't have to sit there and hold it after I have the putty molded to the rock.