At some point, every potter will encounter a warped plastic bat. Good news—you no longer have to toss them out and replace them because they’re actually pretty easy to fix!
We have all abused the bats by setting them in the sun, blasting them with a heat gun, or using them as glaze bucket lids. Eventually the standard methods of turning them over, using a bat grabber, or fastening them down with wads of clay becomes tiring. Let’s make them flat again.
At about 212°F, the plastic will begin to soften. At that temperature, the bat can be made flat again by clamping it to a flat surface while it cools. The bat will be more stable on the wheel head if the center is slightly higher than the outside.
All my bats are 14 inches in diameter so I used a metal automobile oil drip pan to boil the water as the bats fit into it perfectly. Set up the pan on a ring of insulating bricks and heat it with a raku burner. If you don’t have a raku burner, a large hot plate that gets hot enough to boil water will also work. Craftsmen that work with sheet plastic can use an electric oven. A kitchen oven or digital kiln might work but I have not tested that. When the water boils, put a bat in for five minutes. Boiling the bat in water for five minutes evenly heats the surface and core. Use tongs to remove the bat and immediately place it in your clamping system. By the time the next bat is cooked, the first one can be removed from the clamps. It is fine to boil it longer than five minutes but less than that does not heat the bat enough that it can be bent back into shape.
Center two CDs on a wheel head, banding wheel, or ¾-inch wooden bat the same size as your plastic bat. Arrange eight clamps so that they are handy because there is about a 30-second window to clamp the bat after it has been removed from the boiling water.
My favorite clamping setup became a 14-inch wooden bat on a banding wheel with the two CDs on top. This allows me to turn the wheel after each clamp is placed and provides space under the bat for the clamps. Plastic bats have a matte surface and a shiny surface. The matte surface is the preferred face of the bat, so clamp it with that side facing up.
Successfully fixing the warped bat problem was preferable to the other options and it was fun to work out the details. The bats turned out like new and the process is repeatable.
the author Jim Wylder received his MFA from the University of Puget Sound, and his MST from Portland State University.