Occasionally you will find yourself in a situation—whether it’s repurposing a finished pot or poor planning while making a piece—where you need to drill a hole into fired and glazed ceramic.
Drilling through ceramics is actually not as hard as one might think. I’m talking about the task of course and not the actual material. It’s a matter of having the right tools and a little patience. I will say though, if you are creating something out of clay and you know you want a hole in it, the best thing to do is to make the hole in the leather-hard stage. However if you decide later on that you need a hole and the piece has already been fired and glazed, then the following instructions will be very helpful for the process.
My wife, Jeni Hansen Gard, and I grow a lot of different plants and have a slight succulent obsession. When we have a piece come out of the kiln that has a glaze flaw or is warped, we still like to use it, usually to grow more succulents. For most of our potted plants, it’s important that they grow in a vessel that has a hole in the bottom for drainage, and since our seconds don’t usually have holes in the bottom, we create them by drilling through the glaze-fired ceramic.
Assembling your Tools
First you need to have a proper drill bit, which can be found at most home improvement stores—I typically use carbide-tipped drill bits but I’d recommend diamond drill bits for larger holes. Normal drill bits that are used for wood and metal will not work. You’ll also want a piece of foam or a towel (so the piece you are drilling through can rest on a soft surface), a spray bottle for wetting the piece (this keeps the bit from burning up, and reduces the ceramic dust), tape (which makes it easier to get the hole started without the drill bit sliding all over the place, especially on a glazed surface), safety goggles (always a good idea when using power tools), ear protection, and a properly fitted respirator or a dust mask, and work in a well-ventilated area (1).
Getting to Work
Place your piece on a soft surface, put the tape on the piece, and mark where you want your hole to be. Drill a lot slower and with less pressure than if you were drilling through wood. I’d recommend using a cordless drill that allows you to control the torque and speed with more precision. Spray the piece with a little water (2) and then make contact with the drill bit and start drilling (3). Go slowly and let the drill and the bit do most of the work. If you push too hard or have the bit spinning too quickly, you might crack or break the ceramic piece. The amount of time it takes to drill through the piece varies depending on your clay body and how thick the piece is. It’s important to be patient and not to rush the process as it can sometimes take a few minutes. You might have to add a little more water during the drilling. Stop every once in a while, check your progress (4), and once you are getting close, slow down the drill speed until the drill bit goes all the way through. Volia! Remove the tape, rinse off the piece, and you’re done (5).