01 of 05
Determine What Needs to Be Trimmed
Trimmed feet on pottery gives a nice visual lift and a certain elegance to many pottery forms. The decision to give a pot a trimmed foot must be made before the form is thrown, however, in order to ensure that there is enough clay in the pot's floor to allow for trimming.
The object in trimming is for the pot's outer surface to mirror the inner surface. The pot's walls and floor should be even in thickness, except for the foot ring itself.
The pot is ready to trim when it has reached medium leather... hard. If the clay is too soft, it will clump; if it is too hard, the clay won't cut well and may chatter. Before re-centering the pot on the wheel, check the pot's walls and floor curvature and thickness.
Continue to 2 of 5 below.
02 of 05
Re-Center the Leather Hard Pot
Place the pot upside down as close as possible to the center of the wheelhead, bat, or clay pad. Slowly rotate the wheelhead, holding a finger near the pot. Note where the pot comes closest to your finger. Stop the wheel and move that spot on the pot further in toward the center. Repeat, until the pot is centered.
An advanced method of re-centering the pot is by tapping the pot into the center without stopping the wheel. At first, this method can seem impossible; however, with a great deal of... practice potters can learn to center pots very quickly using this method.
It can be very helpful to keep a bat with concentric rings marked on it, just for trimming. If you trim on a clay pad, scoring rings into it can also be helpful. In both cases, the rings can make it easier to see where a pot is off-center.
If you do a lot of trimming, you may want to look into the Giffin Grip, a tool which both centers and secures pots for trimming.Continue to 3 of 5 below.
03 of 05
Secure the Pot to the Wheel for Trimming
Once the pot is centered, it must be secured to the bat or wheel. This can be accomplished in several ways. For some very practiced potters, they are able to hold the pot in position using a finger on the top (erstwhile bottom) of the upside-down pot. For potters who do not do a lot of trimming, this may not work.
One of the most common methods of securing the pot is to hold it in the centered position with one hand. With the other, place a wad of clay up against the pot and smear downward (with... no pressure going inward against the pot itself) to attach the damp clay to the bat. Rotate the wheel one quarter turn and repeat, still holding the pot in place. Place and attach the second clay wad. Repeat for the third and fourth wads of clay.
Another possibility is to center a pad of clay on the bat, prior to trimming. Use a metal rib to remove all excess moisture before re-centering the upside-down pot on it for trimming. Once the pot is centered, gently press the pot down into the clay pad slightly.
Difficult shapes such as wide bowls and platters, or vases with long necks are usually best trimmed using a clay or bisque chuck. To make a chuck, throw an opened cylinder of clay, wide enough to match the inner floor for a wide form, or just wide and tall enough to support the shoulder of a thin-necked vase. Remove all excess moisture from the chuck, inside and out. Place the on or into the chuck and press down slightly.
Another option, especially if you do a lot of trimming, is to invest in a tool such as the Giffin Grip. This tool self-centers the pot and secures it to the wheel head for trimming.Continue to 4 of 5 below.
04 of 05
Trim Excess Clay Away from the Pot
Trimming away the excess clay from the pot requires a sharp-edged loop tool. Firmly hold the loop tool in your right hand, bracing it with your left. You may also want to place a finger of your left hand on the top of the pot to help keep it steady.
The loop tool should be held parallel to the clay surface. Changing the angle will change the depth of clay that is cut away; too much of an angle and the clay will catch the loop, creating a gouge.
Begin by defining the outside of the foot ring. Cut... away the excess clay from the outside of the foot, then trim the outside of the pot's wall as needed. Work the transition area from untrimmed to trimmed wall so that the transition is smooth and not disruptive to the form.
Now trim the interior area of the foot ring. The foot ring's thickness from outer to inner surface should ideally match the pot's wall thickness.Continue to 5 of 5 below.
05 of 05
How to Judge the Trimmed Pot's Floor Thickness
Your upside down pot, with the air that is trapped within it, can act as a drum. To judge the floor's thickness, tap the bottom of the pot. If you hear a sharp click, then the floor is still quite thick. When the pot sounds hollow when tapped, it has been trimmed enough.
Once the pot has been trimmed, release it from the bat or wheel. Smooth the clay surface with a slightly damp finger or sponge. Sign the pot, if you so desire.