I've never tried using epoxy putty to stick a frag to glass, but this technique works 100% of the time in attaching frags to rock.

Dry off the base of the frag and apply a large glob of gel super glue (no need for brand names - only $1 at my local dollar store).

Place your ball of epoxy in the super glue and put some more glue on top of the epoxy making a superglue/epoxy/superglue sandwich.

Place your frag where you want it mounted and press down to flatten out the epoxy and superglue onto both surfaces. The superglue sticks very well to the epoxy and sets quickly. As soon as the epoxy sets, you should have a strong bond.

I've tried just epoxy or just superglue and they don't hold compared to combining them

The epoxy putty is 'decent' for rough surfaces but requires time to cure. It would be useless on glass, especially if done while the tank is wet, you could *maybe* get it to work while dry. As much as the adhesive methods say they can be done in water it only sorta works. The method listed above is pretty much the best you'll get until the frag encrusts the base.

Milliput aquacape epoxy will stick anything to anything. Ive used it to attach frags to glass. J and L sells it

yup... have been using it for a while. take a while to cure, but, once cure it holds quite well.

Thanks guys for our help! I bought some other glue today at my LFS so I'll give that a go.

I have some GSP that I would like to have on the back glass (I seen it in someone else's tank and it looks very cool) so I was trying to do something similar.