# Cutting a Hole in Glass



## cheseboy

Hi, I want to drill a hole in my glass for my overflow because I want to trash my overflow box for various reasons. I will be using a rotary tool [http://ozreef.org/diy_plans/techniques/cutting_holes_in_glass.html] to cut the hole. The question is how far from the top should I drill the hole? (the hole will be slightly bigger than 3/4") The closer I get, the greater danger for the thing to crack when something bangs agents it or maybe it will crack when I fill it with water. So how far should I place the hole from the top of the aquarium?


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## born2lovefish

All I know about drilling glass is that you have to run water over it the whole time to cool it down.


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## TheOldSalt

You should probably stay about an inch from the top for safety. Lower would be even better, but then you start cutting into your water height too much.

They make diamond hole saws for glass drilling, and it you can find one, they're SO much easier than using an ordinary bit. harborfright has a 1-inch holesaw for six bucks.
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=32400

www.shopsmartexpress.com has a bunch of other sizes.

Oh, and yes, you have to keep water flowing over the hole during cutting and be sure to wear a respirator if the thought of turning your lungs to hamburger doesn't appeal to you.


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## RMC-GoodStuff

I recently setup a small bank of tanks on a central system for growing out fry. The first order of business was to drill the tanks for the return line bulkhead fittings. With a few tools and a little preparation I was ready to begin.











A. Boom Box for tunes. I don't work in the fishroom without tunes.
B. Hand saw for cutting wood template.
C. Tape measure.
D. Drill and diamond clad glass bit. This is a 1-1/2 inch bit for 3/4 inch bulkhead fittings.
E. Hole saw to drill a hole slightly larger than the glass bit.
F. A piece of 1 x 4 pine board with hole drilled with the diamond bit (outside template/guide).
G. A piece of 1 x 4 pine board with hole made with the hole saw (inside template/guide).
H. Two clamps.
I. Water for coolant.
J. Hammer and center punch for answering dumb questions by the smart azz neighbor. (Optional)

Board "G" will be used inside the tank so I placed the hole X number of inches from the end to where I wanted to drill my tanks. The board is optional but it adds support to the glass and helps minimize chipping when the bit pops through.










I clamped the boards so that the glass was sandwiched between them and the holes were aligned. Board "G" is inside the tank. I think I was listening to Ozzie at the time.










As you can see, the holes are aligned with the larger hole on the opposite of the glass from where I will be drilling.










Next, I filled the hole with coolant...............










and started drilling. A moderate amount of pressure should be applied otherwise the life of the bit will be shortened. Drilling through the sides of these 30-gallon tanks took approximately 2 minutes per hole.










The end result.


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## fish_doc

Nice, and thanks for posting the pictures to go along with it. It really makes the process come alive.


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## Ownager2004

Wow, I dont have any helpful tips, but the hammer and center punch comment was one of the funnier things ive read in awhile, LOL


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## ronmarsh99

Here is a video for you to watch before you start.
http://www.youtube.com/watch?v=Z5XpHos4SLs
I will be doing this in time to my tank as well but I will be putting the hole on the bottom
of the tank.
oh here is some glass cutters on E-Bay , there real cheap.
http://shop.ebay.ca/?_from=R40&_trk...w=glass+cutter+hole&_sacat=See-All-Categories


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## ronmarsh99

opps just seen how old this post was!!


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## Chard56

Digging up old bones, it happens to the best of us!


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