Drilling a glass tank

[the new guy matt]

Hi,
I just got my 140 gallon tank up tonight!
I have a 50 gallon all glass aquarium in the basement as my sump. I have the 2 intake hoses going into one side , but it would be a cleaner setup if I had 2 bulk heads on the side an inch or 2 below water level. Has anyone successfully drilled a glass aquarium?
It has a tempered bottom but I believe the sides are normal glass.
Thanks , Matt

[Monique]

thanks for asking this question, Matt. I have been struggling with this same thing for 2 weeks now. been phoning around town, and no-one will touch my tank to drill it. so far, all I know, is you can get bits to do it yourself, but only up to half inch....not enough to keep up with my filter. wanted a 2 inch hole for gravity feed to other tank, how many holes will I need to keep up with pump, and will this weaken the tank? If I decide to go that way....

[squid]

Most glass places won't touch drilling a tank because of the real possibility of it breaking. Some places will do it, but won't guarantee anything. If it breaks, your tough luck.

The other issue is the stress level it will put on the tank if done incorrectly.

I'm afraid you might have to use a hang on overflow.

[the new guy matt]

I am an auto mechanic & I am a big DIY type of person. I would think if given the correct instructions & drill bit , I should be able to do it myself. Are there any articles in the DIY section about this?
Icouldnt find any.
Thanks for the replies, Matt

[Doug1]

I dont think I have archived anything on glass drilling. The proper bits to drill glass are expensive, and not worth a one or two hole investment. I watched the guys at the glass shop my sone worked at spend half hour setting up and drilling my 75, they said they wouldn't to them again.
On the other hand my friend drilled his 75(same as mine, AGA 75E) with a dremel and an abrasive stone, built a clay dam around the area and ground through, then tricked water on it will he ground it to size with a carbide cutter as I recall. It took about an hour each hole for 1" bulkheads. Also he managed the LFS and had drilled smaller tanks this way so it was not a first time thing, plus he didn't pay retail , FWIW.
The normal bit used looks like a hole saw with abrasive bonded on edge rather than teeth, its set in a drill press type affair, a clay dam is built around it and diamond dust added to increase the abrasiveness, slow steady pressure, backing off enough to let the bit cool and keep it wet, seems to be the trick

[RWD]

My lfs does it with a diamond bit. They use a drill clamped into a portable drill press. The press is then clamped to the tank. A dam is formed from clay and a small slice of pvc pipe and put around the spot where the hole will go. A small amount of anti-freeze is poured into the dammed- off area and the drilling begins. Using a medium speed it takes about 10 min to go through the glass (1/4" I think). I watched to whole process when I had my 40 gal. breeder sump drilled.

[thefatman]

i had my 75g aga drilled at a local glass shop. they did the same thing. diamond bit, portable press that clamped to the tank. clay dam and cooling liquid.

took about 15-20 minutes per hole.

fwiw, i'm a huge diy person too. i've built most everything for the tank and stand. however the cost of a diamond bit for the size i needed was well over 50 bucks. the cost of drilling was only $8.00 per hole.

as lise said, my glass shop would not guarantee against a breakage during drilling. however they have only 1 person drilling there, and he has been drilling for 30+ years. had no problems. he said his break ration was less than 1%. and he had done a number of tanks in the past.

fwiw: i'd get it done. like doug said, its not worth the cost of the bit for a one time deal. even if you upgrade later (you will) i still cant see justifying the cost. (at least i wouldnt be able to.)

look at it this way. say 60-75 bucks for a bit. maybe an even hundred for a portable press. maybe 5 bucks for some modeling clay. then what if it breaks. now we're at another 70-100 bucks for a replacement tank.

now, 8 bucks per hole sounds awfully cheap doesnt it

[dwall174]

For those that want to try HERE'S some more information on drilling glass. IMO this is a job best left to the professionals.