Sunday, June 1, 2008

How to Throw a Large Bowl on a Pottery Wheel

How to Throw a Large Bowl on a Pottery Wheel
A large clay bowl glazed with two tone engobe
Typically the larger an item made on a potter's wheel the more difficult to make. Greater mass spinning equals greater momentum. This greater momentum of an object is often too much for the weak unfired clay to take and stay coherent. That's why there is a need for a guide that deals specifically with large items thrown on a potter's wheel. In this guide we will use a simple bowl, but the principle for most objects is still the same.

Things You’ll Need:
Potter's wheel

A lot of clay

Damp sponge

Throwing a Large Bowl
Step 1:
To throw a bowl or a plate, you do not need to form a cylinder. Center the clay and open it as usual. Then, instead of bringing the wall straight up, make a bowl shape by widening the opening and bringing the walls up and outward at the same time. With most large objects, the clay should be brought outward or upward, but it is very difficult to do both as it puts too much clay away from the pieces center of balance.

Step 2:
Use the heel of your right hand to enlarge the opening and force the wall outward. Your left hand supports the clay on the outside, fingers keeping the clay from bulging out at weak points or losing their symmetry.

Step 3:
Slowly bring up the wall outward by gripping the clay with the tips of your fingers, one hand on the interior and the other on the outside, and lifting upward.

Step 4:
When the wall is at the desired height and distance from the center, it is now time to thin and smooth the interior of the bowl. With the wheel moving at normal speed, place the tip of your thumb to the very center of the bowl and lighting draw it to the lip of the bowl. To keep the bowl from growing trace your thumb from the lip back to the center. This will help to evenly distribute the clay of the bowl and avoid thick or thin spots.

Step 5:
In order to shape the base or foot hold your right hand just about the rotating surface of the wheel and press it inward to the outside base of the bowl. The middle finger should skim against the surface of the batt and your index finger should dig into the pinch point of the bowl, parting the clay in order to help define the exterior shape of the bowl. Let the left hand ride on the rim of the interior to keep it from being pushed inward by the right hand.

Step 6:
With the wheel moving slowly wipe the entire bowl down with a damp sponge to finish and smooth the surface. You're finished!

Tips & Warnings
The quicker you work the greater likelihood you'll succeed in making your bowl. If the clay begins to dry out there's a good chance it'll crack while you're working it, but adding more water to clay while working it will weaken it too much to keep its shape.
The larger you make your bowl the greater chance it will become unbalanced and collapse. You might want to start with a small bowl and slowly increase the size of each successive piece.

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