I second Lapja's method with a few changes. I've used a hand drill, drill press, or a special tripod drill for drilling glass all with success. The key is backing off the pressure when you get to the end of the hole. Since you're using a drill press you can set the stop to just below the hole which helps. Duct tape underneath the hole keeps the glass plug from doing any damage to the tank once the hole is through. I always use the damn around the hole, whether it's putty or a piece of pipe with a bead of silicone as a seal. When you drill lower the bit down in the hole and let it go for about 10-15 seconds then bob it back out letting the water flow down into the groove to keep the glass cool and the grinding out. Heat is the killer when drilling holes in glass. I've drilled many holes in 1/4 mirrors and glass this method works 100% of the time. Also a good bit makes all the difference. Oh yeah great job so far your fish room is you of my life long dreams.
Last edited by Pickled_Herring; 07-06-2012 at 04:19 PM.
Reason: hit post too soon