How to drill a glass aquarium


How to drill a glass aquarium

With a little confidence, some patience, and a variable speed drill, you can put a hole in your tank. I’m serious. Sure, you could buy a pre-drilled tank from your local fish store, or pay to have someone else do the job for you—but if you are the adventurous type, you can do the job fairly easily. In this article, I will show you how to drill a glass aquarium.

How to drill a glass aquarium

How to drill a glass aquarium for a standpipe like this

The best part about learning how to drill a glass aquarium is the sense of accomplishment you will have when finished.  All you will need are a few tools, a steady hand, and some nerves of steel.  The nerves of steel are most important during the first 5 seconds of the task, but it just may be the longest 5 seconds you have ever spent in the hobby.

Before I actually took the plunge and drill my first aquarium, I was tentative.  You know what, tentative isn’t strong enough of a word–I was AFRAID to take a moving, spinning, whirling piece of metal coated with diamond dust towards your prized glass possession.  And, quite frankly, I’ve only ever drilled 10 and 20-gallon aquariums for my aquarium rack–not my display tank. But you can do it too, if you just hold your breath (figuratively), grip the drill with white knuckles, and see if you have the constitution to complete this intimidating, but not that complicated Do-It-Yourself task. I don’t have a perfect record. Out of 10 tanks that I drilled–2 cracked, and 8 survived–so I’m not an expert, but I do know the basics on how to drill a glass aquarium.

diamond coated drill bits for cutting through glass

Diamond-coated drill bits for cutting through glass


You may have all the equipment you need for your DIY drill aquarium glass project, but if you are looking to pick up some of the equipment listed here, I have provided affiliate links to some highly reviewed products on The way affiliate links work is that Amazon will provide me with a small commission if you buy a product thereafter visiting via one of the links below. They do this at no additional cost to you and it is one of the ways I offset the costs associated with this website. No pressure at all, but if you are invested in shopping there anyway and want me to get a little credit for it, I am grateful, thank you. Sorry or the lame disclosure, but I think it’s important to be transparent.

  • How to drill a glass aquarium article
  • Variable speed drill you can operate easily at a low-to-medium speed (affiliate link on Amazon)
  • Diamond coated drill bit of the appropriate size (see chart at the bottom of the page). (affiliate link on Amazon)
  • Bulkhead (affiliate link on Amazon)
  • Plumber’s Putty (buy this on Amazon with this affiliate link if you want)
  • Water and water bottle capable of squirting (affiliate link on Amazon)
  • Disposable packing material or padding
  • A glass aquarium made with non-tempered glass
  • Safety equipment (gloves, safety glasses, GFI outlet if using electric nearby)
  • Clean-up supplies
  • A stiff drink (if age appropriate) to celebrate your accomplishment
bulkhead creates a waterproof seal through aquarium glass


How to prepare the aquarium glass

1)    Clean the glass aquarium both inside and out in the area you are about to drill. You want to avoid having any dirt, gravel or other substance interfere with your grinding.

How to prepare the aquarium glass

Note the ring of plumbers putty and the water inside the ring

2)    Create a dam around the drilling area of the glass with a small amount of plumber’s putty smoothed out into a circle larger than your drill bit.

3)    Fill the area inside the dam with cool fresh water to lubricate and cool the drill bit.

4)    Place newspaper, bubble wrap or another disposable padding inside the tank to catch the glass circle which breaks free when you have completed the hole.

How to drill a glass aquarium

Begin drilling the aquarium glass

Start with your drill bit at an angle to create the first groove

5)    The next step in how to drill a glass aquarium is to actually begin drilling the aquarium by holding the bit inside the pond formed by the putty dam at a side-angle to the glass. You just want a small part of the bit to catch and grind in slowly.  Your goal is to press only hard enough to keep the bit in place without kicking out.

6)    While drilling, apply a light, constant pressure and slowly tilt the drill upright, extending the groove in the glass outward from the initial cut.  By the time you have stood the drill up (leveled it out), you will have worn a fine groove into the aquarium glass in a complete circle. At this point, you likely have a complete circle but have not gone completely through the thickness of the glass

Continue drilling the glass aquarium

That small ring inside the putty dam is the hole you are grinding

7)     Continue drilling with a slow to moderate speed while applying a constant, gentle pressure to grind completely through the glass wall. Expect the grinding process to take about 3-5 minutes for a 10-20 gallon tank.  Thicker glass will take longer to drill through than thinner glass.  I found that amount of time to be a comfortable, cautious pace for my first time.  If you rush, you run the risk of causing the bit to ‘kick-out’, scratching the aquarium glass and ruining your nerves again. If that happens, just start over at the beginning of the groove and slowly work your way back upright.

drill breaks through the aquarium glass

the milky white particles are shards of glass

8)    When the hole punches through the inside of the glass, the water inside the dam will drain through, so be sure to have a water bottle nearby to squirt the drill bit, keeping it cool and lubricated.


clean up after drilling aquarium glass

DO NOT DO THIS–I was picking tiny shards of glass out of my fingers for days

9)    Use extreme caution to clean up. The milky-white ‘sand’ you see is sharp glass. The inside of the hole you cut is sharp glass. The outside of the circle that you ‘punched through’ your aquarium wall is sharp glass. Did I mention sharp glass? Carefully clean and dry the glass before installing the bulkhead according to the directions listed by the bulkhead manufacturer’s directions. Incidentally, I did not wear safety equipment on my hands–and I was picking tiny shards of glass out of my fingers for a few days afterward. Nothing that caused major bleeding or cuts–just constant, raw irritation.

Popular Bulkhead Sizes

how to drill a glass aquarium

The bulkhead is the most important part

When shopping for a bulkhead and diamond-coated drill bit, play close attention to the product descriptions. You need to confirm:

1)The size of plumbing the bulk-head will accommodate,

2) The diameter of the hole you need to cut.

For example, a bulkhead fitted for a one-inch PVC pipe requires a 1 ¾ inch hole.  Always read the specifications carefully when you purchase your bulkheads and be sure to purchase the correspondingly sized drill bit. Here are a few examples of common bulkhead sizes and the necessary hole you will need to cut in order to accommodate that size bulkhead.

Desired Plumbing Diameter

Hole Size

1/2 inch 1 1 /8 inch
3/4 inch 1 1/2 inch
1 inch 1 3/4 inch
1 1/2 inch 2 3/8 inch
2 inch 3 inch

(source no affiliation

Three important things to consider about how to drill aquarium glass

  1. Think of this process as slowly grinding away the glass rather than drilling through it.
  2. Don’t ever try to drill tempered glass. Ask your local fish store for an aquarium made without tempered glass
  3. Practice on a spare 10 or 20-gallon aquarium first, to build up confidence before you drill your display tank

Watch this video

To see this in action, check out this video:


What I like most about the aquarium hobby is the opportunity to create, design, and personalize our tanks.  We create our own aquatic footprint.  When I overcame the irrational fear of drilling my aquarium, I found it liberating and fulfilling to take my aquarium design to the next level.  I encourage you to take a deep breath and take the plunge by practicing on a spare 10 or 20-gallon aquarium first, to build up confidence before you drill your display tank. In all fairness, I did crack 2 out of 10 tanks, ending up with 8. Just know that if you are taking a drill to the glass–you could lose the whole tank–so if you’re not comfortable with that risk–you may want to trust it to an expert (or purchase a pre-drilled aquarium), but if you think you have the courage to do it your self, I hope this guide on how to drill a glass aquarium was helpful.

Next step

Now that you know how to drill your aquarium to insert an overflow. The next step is to install an aquarium sump.

Learn all about aquarium sumps here.

and watch this video:

Written by Al Ulrich

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