How to Drill a Hole in a Glass Aquarium The Easy Way


How to Drill a Hole in a Glass Aquarium the Easy Way

While most fish keepers start off with easy, off-the-shelf filters from the pet store, some hobbyists want to take their aquarium filtration to the next level. By drilling a hole near the top of a fish tank and adding a bulkhead (i.e., waterproof plastic fitting that prevents the hole from leaking), aquarium water can be directly plumbed out of the tank and into a custom filtration system – like an aquarium sump, canister filter, or automatic water change system.

Each person has a different method of drilling glass tanks. We’ve tried all methods and have drilled hundreds more aquariums for our fish shop and personal fish rooms. This article explains the tried-and-true technique we eventually landed on. Drilling glass comes with its risks. Wearing safety gear is a good idea. We are not responsible for any damages, injuries, or losses that you might experience during this DIY project. We have found that the more thick the glass is, the less likely it will crack. Aquariums with a volume less than 40gallons are made of thinner glass. They tend to break between 10-25% of all cases.

Materials for Drilling Aquariums

– Glass aquarium that is not tempered Bulkhead (slip x slip) – Diamond-tipped hole saw that matches the size of the bulkhead – Electric drill – Clamp – Pitcher or bottle of water – Flat piece of wood that is about 1-inch thick – Sharpie marker or pen – Painter’s tape – Pliers – Safety glasses – Safety gloves

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Although some aquariums use tempered glass as the bottom panel, most others use non-tempered glass to make the side walls. You can check the side walls of your aquarium by placing a computer or mobile phone in the tank. The pane of glass will be drilled so that you can view the screen. You should ensure that the screen of your device is white. While holding a pair polarized sunglasses in each hand, you can look at the device’s screen. Next, rotate the sunglasses like a steering-wheel. If the glass is not tempered, the screen will look like it is shifting from white to solid black as you rotate the sunglasses. When the sunglasses are rotated, you will see splotches or stripes on the screen if the glass is not tempered. Look online to see video examples that demonstrate this effect.

Instructions for drilling aquariums

1. Place the aquarium on its side so that the tank wall that will be drilled is facing upwards. Place the piece of wooden against the tank’s side edge. The hole saw should be placed where the bulkhead will be. The hole should be low enough so that (a) the overflow or drain is at the surface of the water and (b) the locking nut of the bulkhead won’t hit the rim while tightening it. Also, mark the wood so you know which side of the wood is touching the rim.

1. Drill a hole in the wood at the spot you have marked with a dot. A hole saw made for wood is best. If you decide to use the diamond-tipped hole saw, it will do the job but the wood may smoke a bit.) The guide is now used to make sure the hole saw doesn’t move when drilling. 2. After the guide is made, line up the piece of wood against the side edge and the rim of the tank again and clamp it down. Tape the aquarium’s interior where you can see the hole to ensure that the glass will not come out and crack the tank. The tape helps to reduce chipping and makes the hole look clean.

1. You can fill the hole with water. Some of the water will leak out so you will need to keep refilling it to keep the glass sufficiently wet. Water is used to remove dust from the hole saw and prevent it from heating up.

1. Squeeze the trigger on the electric drill so that it spins at a slow pace and gradually increase the speed to a moderate pace. Use a gentle, even pressure to the hole saw and allow the drill’s weight to pull it down. The hole saw should be kept level. Do not tilt the drill to make the hole uneven. You want to gradually file your way through the glass. The drilling step could take between 5-20 minutes depending upon the thickness of your tank.

1. You can add more water to the hole saw or into the guide if the glass makes a squealing sounds. Next, drill more. 2. When frequency of the grinding sound starts to change, the glass hole is about to or has already broken through. There may be some slightly jagged edges on the hole, but the bulkhead’s gasket will cover them so no need to deburr the hole. Carefully pull off the tape, and do not touch the inside of the glass hole.

Diagram bulkhead fitting

1. The bulkhead is quite fragile so make sure to place the aquarium in its final position before you attach the bulkhead. The bulkhead should be inserted through the hole, so that the gasket and flanged head are on the tank’s inside and the locking nuts on its outside. Tighten the locking nut with your fingers and then finish cinching it down with pliers.

Congratulations on drilling the first aquarium! A final tip: make sure to use high-quality hole saws, and that they are replaced regularly. The hole saws we bought can drill about 8-10 tanks before they wear down too much. Your aquarium is more likely to break if you keep it in use for too long. If you plan on drilling many tanks, get a pack of multiple hole saws and save yourself the headache. You can also stock up on bulkhead fittings that our family uses in our aquariums and fish shop.