As little pressure as possible, and do it in the sink (etc) so that the surface to be drilled is just under water. Bits that are designed to handle glass generate a LOT of heat, so you have to keep water moving over it to keep the glass from cracking from the bit itself. Glass bits also generate a lot of glass particles in the air, which you really do not want to inhale, and drilling underwater should contain most of them.

If you're really worried, you should go pick up some random glass bottles and practice a few times. Keep in mind that any seams/bends/etc in the glass will probably be weaker spots less able to handle stress.
WaZ Reviewed by WaZ on . Glass bong : need help Hey all ok, so a few friends an i had the good idea of makin a bong outta a glass bottle instead of a plastic one. The pro's are that the glass is more durable, doesn't warp if it gets hot, and it just looks so much better! So i went out last week and spent bout $20 on glass drills only to find that any bottle we drill into bursts, shatters or just chips to shit. Now, i'm a student. So cash is hard to come by, an here in south africa $20 is 2 shifts of work. So i'm a lil pissed that i Rating: 5