Mr. Saltwater Tank

Terrible Advice Tuesdays (T.A.Tues): The Secret To Drilling Tempered Glass?

Terrible Advice Tuesdays: Tempered glass can be drilled. Just apply slow pressure on the drill bit.

The rest of the story: Give that technique a try and let me know how it works for you!

Tempered glass can’t be drilled. If you drill it, the glass will shatter. This fact is why a lot of mass manufactured aquariums have a sticker on the bottom of the tank that clearly states the glass is tempered.

How to do tell if a piece of glass is tempered? The easiest way is to put on a pair of polarized sunglasses and look at the piece of glass. Black lines will appear on the glass especially when you rotate your head and look at the glass sideways.

Note: I did find this article on eHow telling you how to drill tempered glass. I’ve never heard of this technique before and I didn’t find it on any other searches so I’m extremely skeptical that it will work.

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Comments for this article (24)

  • Angel says:

    Drill it…. I dare you..

  • Steve says:

    I think that is a mis-type in the name of the article.
    All the steps and directions look like everything I’ve seen and read about drilling Non-tempered glass.

    I would take this with a grain of salt and not attempt it without at least trying it on a scrap piece of glass first.

    I still think it’s a long shot.

  • Luis says:

    Good luck with that!!!!!!!

  • James says:

    I have seen the exact method mention and it worked on only one piece of tempered glass, the other sheets shattered and the guy was a pro glass cutter/worker, he said the reason it shattered was due to the age and use of the glass, he was right as the old pieces came from the cabinet was years old and the piece that worked was less than 4 months old, with a stamp saying when it was made… so there are many factors to take into account when drilling tempered glass,,,,,, good luck

  • Kyle says:

    Drilling three holes in my newly acquired 90 gallon days after getting it was probably the most nerve-racking experience I’ve had in this hobby. Very gratifying though to know that I did it and didn’t end up shattering a perfectly good tank. 🙂

  • JasPR says:

    How to turn an aquarium into a trickle tower 101:
    Take a standard aquarium with a tempered glass bottom and drill a hole as if you were trying to cut an opening for a bulk head overflow kit. Second step- after applying the drill and water cooling set up, use a broom to clean up the shattered aquarium base. Remove excess splinters still clinging to the frame and insert egg crate as a support shelf for your plastic media. install this new four sided biofilter glass cage ( former aquarium) to the top of your sump and you now have a trickle tower on your sump. Firmly plant tongue in cheek and pretend that this was done on purpose and not an attempt to drill an aquarium with a tempered glass base. 🙂 JasPR

  • That’s funny JasPR. Maybe that’s what I do for a show next April Fool’s Day!

  • Good point Steve.

  • Duane says:

    I got a new 55 gal and tried drilling the long side glass. I drilled it just as the above eHow article suggests. It was tempered and unmarked. Half way through the drill it shattered into a million pieces. I know to never drill the bottom glass, but was surprised the side glass was tempered. I have drilled many aquariums without a problem. Another way to know if the glass is tempered: drill it… if it shatters into a zillion little pieces, Yep… it’s tempered! Tempering glass not only makes it stronger, but it also makes it safer, thus “safety glass”. It is used in cars side and rear glass, table tops, etc. It is made to break, when under stress, into a million little pieces rather than large knife like shapes. So… tempered glass will shatter when under stress (ie. drilled). It is made to do so.

  • Steve says:

    It depends on the tank and the manufacturer. I had a 125 that was able to be drilled through the bottom.
    Now my 55 has a sticker on the bottom that says this side is tempered Do not drill.
    So that leads me to believe only the bottom is tempered and not the sides.
    I haven’t tried it or do I think I’m going to on the 55. I don’t see this being my final tank,it’s too narrow.

  • Eric says:

    Mark, that article you linked for drilling tempered glass is more than likely misnamed. That’s the same procedure I have used for drilling non tempered glass, and if you search youtube you can find people “attempting” to drill tempered glass with that same method. The results are always hysterical.

  • Austin says:

    Umm… It’s hilarious that people actually try in the first place. Good luck if you choose to ruin a tank.

  • You find the funniest advice.. If you’re going to invest so much into your hobby why not just have it drilled before you bring it home? The old adage is”Penny Wise, Pound Foolish”..

  • Darren says:

    I had to replace a 90 and asked the LFS if it could be drilled. He said only the bottom was tempered and couldn’t be drilled. There was a sticker on the bottom but it said ” do not drill tank. Tempered glass”. Called manufacturer and it indeed was all tempered. Never even considered drilling it.

  • Andrew says:

    I have a Fluval Spec V… There is nothing on the tank that says it is tempered or not. However the glas is super super thin, 1/8″ thick! Well I drilled one hole 1.5″ and in an attempt to get my set up to run one bulkhead with return and drain didn’t work so I drilled a second hole 30mm for a 1/2″ bulk. That was the most nerve racking experience of my life!!! I thought drilling the first hole was bad but the second only inches away on the bottom of an unknown piece of glass! Thank god it worked and the pico build continues!

  • Kevin says:

    If you do buy a tank with a tempered bottom like an aqueon. The sides were not tempered on my tank. So I drilled the side walls about 2 inches from the bottom of the tank and installed a bulkhead as normal. Works great! Been up and running for the last couple years so far.

  • Shawn says:

    This is off topic!!! But I heard a myth that you can’t mix salt in a trash can cause it releases phosphates in the water. Is this true? I’m using a Brute food grade one & need to know if I’m doing any harm.

  • Shawn…some trash cans are made of a plastic that releases phosphates around water. And I don’t worry about it as the amount of phosphates that might get into your tank is small.

  • Sarah says:

    so I drilled it. (not having read the advice) It’s going slowly but that’s ok. I take bio break – go back and there are many little pieces of glass on my bench.

    Sadly this leaves me with and AWESOME flying saucer with no lid – and a show in 5 days. bummer.

  • Sean Skjonsby says:

    Hi there, Tempered glass can be drilled. I have seen it done on aquariums but it’s a special technique. If you take a piece of normal glass the same thickness as the tempered glass and cut it into say 3 inch by 3 inch square and silicone it where you need to drill the hole and let it cure. Drilling from the inside outward. You need to start drilling the non tempered glass first and when you hit the tempered glass the normal glass holds the energy in the tempered glass so it won’t shatter.


  • Oberon says:

    Glass physics 101. Tempered glass has three layers – surface compression, center tension, other surface compression.

    If you pierce the compression/tension layer from either direction you release stored energy that results in lots of little bits of glass.

    There is NO way to cut or drill tempered glass without it shattering. Not waterjet, not laser, not plasma cutter, not diamond drill or saw, not underwater, nothing.

    Speed and care has nothing to do with it. It is simply physically impossible.

    If you THINK that you have cut or drilled tempered glass you are wrong.

  • Bob says:

    I have personally drilled tempered glass with a 1″ hole saw diamond Dremel bit it was a dry bit on my 18volt drill it went through fine .problem was hole was too small and as I was reaming the hole just a bit bigger to cut what I needed ..pooofffff…glass bits everywhere so it can be drilled ..will it still be strong after I have no idea but it can be done I’ve done it

  • Well worth a read. Got great insights and information from your blog. Thanks.

  • Tim says:

    I have a tank that’s drilled but is tagged tempered.

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