The Basics: Trimming
Introduction
Trimming is the process of using a tool to remove clay from your piece after it has dried to a state we call ‘leather hard’. It is also during the trimming stage that you add a foot to your piece.
When to Trim
It is time to trim when your clay becomes ‘leather hard’. A ‘leather hard’ piece is defined by its resistance to shape altering pressure – if the clay is cool to the touch and your finger leaves a subtle indentation when you press it, then your piece is ready to be trimmed. Clay that is too dry to trim will be chalky and resist any pressure. Clay that is too wet to trim will alter shape when exposed to small bouts of pressure.
Tools
We enlist the help of a local blacksmith to craft our trimming tools. However, we understand this is not the sensible choice, so we’re providing a link to Diamond Core Tools. Diamond Core Tools is our go-to destination for trimming tools and other miscellaneous sanding tools.
Centering
The first step is to center your piece on the wheel. Start by spreading a layer of water over the rim of your piece. Then place your piece on the wheel and hold it lightly with the pads of your fingers, without too much pressure so that it continues to spin in your hands. You can tell the piece is centered when it grows silent. By silent, I mean it stops wobbling in your hands. The wobble of a piece while attempting to center it is what we call ‘noise’. It’s O.K. if the rim of your piece is wobbling, the only part you are worried about is the junction where the floor meets the walls of your piece.
Notice how the rim of her piece is still wobbling – like I said, that is O.K. But, pay attention to the angled section of her mug, the edge that connects the floor to the walls – there is no ‘noise’.
*Pro Tip
After centering, take a small piece of clay and divide it into 3 sections. The clay should be wet enough to stick but, not so wet that it will integrate with the piece you are trimming. This can cause deformities on the walls of your piece. Press down on the clay lug so that it forms a right angle, connecting your piece to the wheel and providing a secure hold. You can see these lugs in the video below.
Trimming
This step may vary based on the tools you are using. However, we always include a foot when we are trimming. The foot of a piece can provide an elevated flair, and more importantly it helps the glazing process. While glazing we hold our pieces by the foot and deftly lower them into a bucket of glaze.
Notice how Kim keeps both hands connected – one hand should always remain on the piece. Her trimming tool is angled, so that the edge catches the clay, resulting in coiled loops that exude from the piece. She starts by leveling the floor, then trims the walls of her piece and begins shaping her foot.
Final Steps
Leaving sharp edges on the foot of your piece causes cracks, breaks, and chips; so we round off the edge of the feet at the end of the trimming process. To do this, get your fingers wet. After wetting your fingers, firmly press them against the sharp edges of the foot as the wheel continues to spin. Once you are satisfied with the shape of your foot, carefully remove the 3 lugs of clay from your piece. Finally, use a wet sponge to gently smooth the rim of your piece.
*Pro Tip
After trimming all of your desired pieces, take leftover scrap and throw it in your clay bucket to be used in the reclaim process!
Written and Edited by: Cole Vincenzi