<a href=showthread.php?s=&postid=5834657#post5834657 target=_blank>Originally posted</a> by fishmon
The tank IS empty I assume? If so its actually pretty easy, I have probably drilled 100 or so holes, give or take, and only cracked one and thats because I slipped w/ the drill. Also the fact that it was a 20gallon tank (thin glass). Thicker glass is less prone to crack IMO. All you need is a diamond tip hole saw, just do a google for glass hole saws. They aren't cheap about $60-80 for a 1". But if your drilling 8 holes, the average glass shop charges $10 per hole. Start w/ a scrap piece of glass and Just mark where you want your hole, put a "dam" of clay around the hole, slightly larger than the size your drilling, fill the inside of the dam w/ water and then get your drill up to about medium speed. Keeping the dam full of water is VERY IMPORTANT!! ( I have used cordless drills for this but I like the power of a corded better) When drill is up to speed start the hole saw at an angle touching the outer edge of the bit to the outer edge of the circle you have drawn out. As the bit starts to cut, SLOWLY roll the bit down flush w/ the glass as you increase the speed of the drill. once you have started a groove in the glass just let the weight of the drill do the work. DON'T PRESS HARD. Go slow until you feel the bit penetrate the other side, ease up on the drill and keep speed the same. Out will pop the glass plug and you have your hole!
Hope this helps.
