A Surform, a tool originally designed for woodworkers, is so efficient at removing clay that it is not only found at the hardware store but also at most clay supply stores.

It’s been so long it’s hard to remember not using a Surform in the process of completing handbuilt and wheel-thrown pieces. First, I used a Surform that was long and straight. I would break it in half so it was shorter than the smaller curved Surform that I use almost exclusively now.

When clay is leather hard, planing the surface with a Surform removes the bumps and flattens the surfaces while also creating an interesting texture. You can leave the texture or smooth it away easily with a metal rib. The Surform also enables you to alter forms in endless ways, creating new lines and curves, removing more or less clay where you want it to achieve the lines of the form you desire.

A Surform is a great tool to level rims as well. If you’ve experienced trying to do this with a knife, you will have discovered that it can be tricky. With the Surform, you have much better control over the lines you are making. A lot of my thrown forms are squared during throwing so trimming off excess clay and making the lines of the form flow are easily and quickly achieved with this tool. I like this way of working and also like the feel of the end result so much that I often hand trim round pieces with a Surform and metal rib. I feel the entire form becomes more relaxed, and all of the parts relate to each other visually.

1 Using a Surform to remove excess clay from the lid made for a squared, wheel-thrown form. 2 Using a Surform to shape the knob on the lid. 3 Hand trimming a vessel with a Surform. 4 Removing the tool marks from the Surform with a metal rib.

When you use a Surform blade on its own, it’s not that comfortable to hold and use for any period of time. That’s how I came to putting the small curved file in an old credit card so it’s super easy to hold and use. The replacement blades are easy to find in the hardware store, your local clay supplier, or online. If the credit card doesn’t work for you, there are also comfortable, commercially made handles available at most clay suppliers.

the author Cathi Jefferson is a potter and instructor living near Duncan on Vancouver Island, British Columbia, Canada. See more of her work at www.cathijefferson.com.Have a great tip? Got a new tool hack? Let us know at editorial@ceramicsmonthly.org. If we use your idea, you’ll receive a complimentary one-year subscription to CM!