Believe it or not, but some people have tried to use hot glue guns to mount corals to frag disks. Let me tell you though, that this method has a high rate of coral death. The glue is extremely hot and cools down very quickly. When you put the coral into the glue, it causes a great deal of stress and will likely kill the entire frag. Some frags will survive the ordeal, but just stick to cyanoacrylate-based super glue gel and the different reef safe epoxies for all of your coral fragging.