Drilling a Tank

[MickS77]

This is the process I used for drilling my next display tank. Its a 90 gallon tank with 1/4" inch thick glass. I'm drilling to install bulkheads to attach a canister filter too.

Drilling a tank isn't as scary as you think if you've never done it before. You just have to go slow and have confidence, once you start there is no going back. It is more difficult and more likely to break on thinner glass, 1/8" or less.

The tools I used were:

• Power drill. I think a two speed drill is best. Used on the lowest setting so you can't go too fast.
• Drill guide. I like this one with the suction cup. It held really well and has a port to attach a water line too.
• Squeeze bottle & aquarium airline. The bottle is from Dollar Tree, while not water tight, a thick wrapping of Teflon tape around the threads solves that. I found the Marina blue airline fit onto the nipple of the drill guide the easiest and onto the squeeze bottle. 
• Some flat scrapes of wood and toolbox drawer liner
• Glass drill bit (obviously). I used a 35mm bit for a 3/4" bulkhead.

 

 

I didn't want to do it outside with a hose because it was cold and snowing out at the time. I drilled it in my kitchen without making a mess at all.

 

 

I used the flat scrapes of wood to wedge inside the tank as a brace when drilling. It helps contain everything once you get through the glass and maybe helps prevent some chip out. I used the liner against the glass to prevent the wood from slipping and wedged the piece between them to hold it tight.

 

 

Go time. I wrapped a towel around the guide to contain the glass dust slurry. I had someone help by squeezing the bottle at a steady rate while I was drilling. I used the lowest speed and set the drill's clutch to the drill setting. Use both hands to hold the drill and keep it as straight as possible. Don't push too hard, especially on thinner glass, hold the drill tight and push down lightly, let the drill bit do the work. It takes time to get through thick glass, just go slow. You'll feel less resistance as you get closer to punching through, ease up on the pressure at that point until you're all the way through.

 

 

Once you're through the hard part is over, except getting the plug of glass out the bit. Prying with a screwdriver in the slots gets it out. 

 

 

Removing the guide I found very little mess. Easy clean up. You can see the toolbox liner twisted and caught the bit as it punched through. I think that is actually beneficial, like a soft stop/landing for the process.

 

 

I re-positioned the setup exactly the same and drilled a second hole, also successful. 

 

 

[lefty o]

nicely done.

[Daniel]

This was a much needed video for the forum. Thanks @MickS77!

[Maggie]

Wow, congrats on your success!

[AdamTill]

Nice. I still hold this up as the thing that’s most scary in the hobby until 2.2 seconds into your first drill where it becomes instantly boring lol. I’ve drilled about 40 tanks at this point and only cracked a 5 gallon as I rushed to back the drill bit out after it was through.

I like that guide too. I just use a chunk of plywood myself, but yours is clever.

Edited January 4, 2021 by AdamTill

[Tedrock]

I just found this post and this has given me the energy and juice to try this next phase of tankdom.  Thank you for this thread,

[Tedrock]

The nest question is, diamond drill bits?  What do people recommend? Where is the best place to buy them?  I have about 20 tanks I would like to drill for the fishroom and I know quality of the bits is a factor versus the amount of tanks to be drilled.  Amazon doesn't look like the best place to buy them and Bezos could lose my business for sure. 

[AdamTill]

Don’t spend a bunch of money, Amazon etc is fine. The expensive ones don’t drill proportionally more tanks than the cheap ones, and you’ll be less likely to want to swap out expensive bits.

When they dull they don’t really risk breaking tanks etc, it’ll just take noticeably longer to drill. I’ve used a couple WAY past when they should have been turfed, and you just need to be patient.

2 bits should be lots for 20 tanks.

Technique wise my 2 cents is that I like to do something I can’t recommend from a safety perspective, but that works for me. I remove the battery on my drill, and use a zip tie to pull the trigger. Then I align the bit in my guide, and snap the battery in place to start.

I do that so I can hold the drill only by the battery end, and only have the weight of the tool do the cutting. I get barely any breakouts that way, and I’ve never broken even a 5 gallon by pressing too hard. I think most breaks come from people wanting to force the tool to cut faster than they want using force, and holding the trigger gets really tiring after a while.

At your own risk, but it works for me.

[Tedrock]

Both points make a lot of sense I will use that wisdom.

[Andy's Fish Den]

I've drilled quite a few tanks, everything from 5 gallon to 125 gallons. The thicker the glass, the easier it is I have found. Make sure you have plenty of water to keep the bit cool and wash the glass dust away. I've used diamond bits from Amazon, eBay, and Jehmco. The ones from Jehmco I found last the longest, with the diamond bits, as they get used it takes longer to drill a hole, if you're only doing a couple holes, the cheap ones form eBay or Amazon will be fine. But if you are drilling a lot because you're plumbing an entire fishroom, invest in a good bit, it will save you time in the long run. Jehmco will also rent a drill press that is really handy if you are drilling a lot of tanks.

[Brandy]

I really really really wish I could drill my tanks...but they are set up. I don't know if I can make myself tear them down and start over. I wish there were a way to drill them with plants and substrate still in there. How likely is that to be a disaster? I assume 90% chance of horrible outcome. This is why I am considering diy overflows.

[Gigrantor]

I've just recently drilled my first tanks, fitted them with bulkheads/silicone sealant (Due to a majority of them leaking without the sealant when water tested), realized I used sealant that isn't aquarium safe, removed the bulkheads, and cleaned up the excess sealant. 

Before I make another attempt with aquarium safe 100% sealant, is there a right or wrong way to get everything water tight? Or is it a just do what you have to do kind of thing? I've cleaned the glass where the gasket makes contact and tightened the bulkhead as far as I'm comfortable going. The videos I've found online are very split on the use of sealant and how to apply. 

[AdamTill]

47 minutes ago, Brandy said:

I really really really wish I could drill my tanks...but they are set up. I don't know if I can make myself tear them down and start over. I wish there were a way to drill them with plants and substrate still in there. How likely is that to be a disaster? I assume 90% chance of horrible outcome. This is why I am considering diy overflows.

The biggest challenge is keeping lubrication water on a vertical surface. You’d also have to be careful that you catch all the bits of glass that break out into the inside of the tank as the bit goes through.

My nightmare would be what happens if you crack a thinner tank with livestock inside. That would be really terrible. If it’s a 55 or bigger not really likely, but on a 20 or smaller the glass is pretty thin. I’ve only broken one in 30+ tanks, but there was that one.

I also don’t know if there’s less margin for error if the glass is already under a water load (as opposed to empty).

[Brandy]

1 minute ago, AdamTill said:

The biggest challenge is keeping lubrication water on a vertical surface. You’d also have to be careful that you catch all the bits of glass that break out into the inside of the tank as the bit goes through.

My nightmare would be what happens if you crack a thinner tank with livestock inside. That would be really terrible. If it’s a 55 or bigger not really likely, but on a 20 or smaller the glass is pretty thin. I’ve only broken one in 30+ tanks, but there was that one.

I also don’t know if there’s less margin for error if the glass is already under a water load (as opposed to empty).

I would remove the livestock and 90% of the water, but agreed, lubricating the vertical surface sounds...nearly impossible. Full with water or even half full, I think would be a disaster. I have watched a 20g high deflect nearly a full half inch with filling.

[AdamTill]

34 minutes ago, Brandy said:

I would remove the livestock and 90% of the water, but agreed, lubricating the vertical surface sounds...nearly impossible. Full with water or even half full, I think would be a disaster. I have watched a 20g high deflect nearly a full half inch with filling.

Yup, exactly. It’s worth taking the time to break them down clean. Having an overflow and auto water changes is SO worth it. I miss our fish room, and if I was maintaining more than one tank right now I’d totally set them up that way again.

Tanks are made so inexpensively nowadays that they’re not overbuilt, to put it mildly.