Drilling glass tanks TOTW 1-24-05

[scubadude]

As we approach the issue of "more flow" in our aquariums w/out powerheads the issue of drilling our tanks becomes inevitable. This weeks Topic of the week in the DIY forum will be Drilling Tanks.

First off we have glass tanks that I want to concentrate on, however there are other tanks out there such as acrylic, plywood, fiberglass, PVC and more, which take a much simpler approach than the glass tanks.

Most important rule DO NOT drill, grind, or cut Tempered glass as it will shatter into a million pieces.

• How do I know if its tempered? There are many different tanks out there and some are easier to distinguish than others. If you know the tank manufacturer then usually you can find out if the panel(s) you want drilled are tempered or not. If you know the manufacturer than you can usually do a search on the internet and locate a phone number to call to find out if they are tempered. If for some reason you cannot find out the manuf. then I suggest taking the aquarium to a local glass shop and usually they can tell you if its tempered.
• Do I drill the hole myself or let a glass shop do it? I personally wouldnt drill glass myself unless its 1/4" thick or less and even then I would be concerned, depending on the circumstances. To drill the glass yourself you will need a diamond hole saw, a very steady hand, a drill or better yet drill press, and time (must be drilled slowly and allow the bit "cool time" in between drills). On smaller glass tanks you can usually be more successful using a dremel with the following drill bits #7103 & #7134 #7144 (Dremel Brand)
• Reinforce your glass by clamping a piece of wood to the back piece of glass (if possible) before you start drilling, this will provide stability and less stress on the drilling point. Take your time and let the drill do most of the work (dont put alot of pressure into the drill/dremel). You also need to keep your bit/holesaw cool during the drilling process, this can be done by using a coolant such as water. If you have a spray bottle this usually works well. Use the spray bottle to clean the glass dust buildup that you see start to accumulate as you are drilling.
• Use eye protection, and gloves when doing this. Dont wanna see anyone get hurt
• If you have a glass shop drill your holes then you can ask them how many holes their bits have drilled. The more holes they have drilled the weaker the bit becomes. Glass Drill bits (diamond grit) are not uncommon to get 200+ drills out of them (depending on the thickness of drills). A good glass shop keeps track of how many drills their bits have made.
• Cost from glass shops can vary. I have paid $60 for two holes that where 2 3/8" big and drilled in my 220g, which seems to be a fair price. The thicker the glass the more it will cost. There are other cost factors as well for example a 20g has thinner glass and is much easier to work on than say a 220g which is made from 1/2" thick glass.
• What size hole do I drill? If you are using a 1" bulkhead then you DO NOT drill a 1" hole most all places that sell bulkheads will give the hole size needed for that size of bulkhead. And for the most part they are the same for all size bulkheads but please double check as there are a few oddballs out there. Heres some generic specs though on bulkheads and hole sizes:
  
  1/2" bulkhead = 1 1/8" hole diameter needed
  3/4" bulkhead = 1 1/2" hole diameter needed
  1" bulkhead = 1 3/4" hole diameter needed
  1 1/2" bulkhead = 2 3/8" hole diameter needed
  

[Reefland]

Rocky,

What percentage would you say, or how common is it, to locate a glass shop that will drill the holes and guarantee their work?

[scubadude]

Rocky,

What percentage would you say, or how common is it, to locate a glass shop that will drill the holes and guarantee their work?

Scott,
Good question...so far I have only had to use 3 different glass shops that drill tanks for me and none of them guarantee, there is one person I know that will guarantee as long as he knows for sure the glass isnt tempered. This person is in the aquarium industry not just a glass shop though. Most of them tell you they havent had a problem yet or they may have drilled alot of tanks and only 1 or 2 have cracked I mean a $40 job on a $1000 tank its kind of hard to guarantee....the only one place for sure that I would really suspect a good guarantee is the manufacturer of the tank.