How to Fix Cracks in Pottery Before Firing

Dealing with cracks in pottery can be a frustrating challenge, but with the right techniques, you can often salvage your pieces before they even make it to the kiln. The key is to address cracks early on, when the clay is still in the greenware or leather-hard stage.

Repairing Soft to Leather-Hard Greenware

Greenware is the ideal stage to catch and stop a developing crack. I recommend repairing cracks or structural issues as you go, as they often start to appear at points of weakness, like where coils are attached or walls meet. The best time to fix these is when the clay is in the leather-hard or soft leather-hard stage.

The counterintuitive solution is to actually open up the crack more. Clay has a “memory,” so scoring the area larger than the crack itself and then pressing in some scored soft clay can help heal it. Compress the repair with a rib to lock it in place. This approach can remedy most cracks, depending on how dry the clay has become.

Repairing Bone-Dry Ware

Once the clay reaches the bone-dry stage, your options for repair become more limited. Attempting to add water, slip, or wet clay will likely just make the crack worse, as wet clay doesn’t adhere well to dry clay.

Instead, try repairing small cracks with a homemade paper slip. Make a thick slip from the same clay as your piece, then mix in some paper pulp (you can use toilet paper) to create a sticky, putty-like consistency. Pack this into the scored crack, adding just a touch of water if needed to help it adhere. Let it dry thoroughly before proceeding.