Throwing, Firing, & Glazing Pots - How To

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How to Throw a Bowl on the Wheel
Clay in bag

Get Out the Clay

Here is a 25lb bag of stoneware clay.

There are a lot of different kinds of clay.
I often use Standard brand clay like this one - 205G.
I use pipe cleaners to close my bags and keep the clay from drying out.

   
Clay on scale

Cut and Weigh the Clay

Use a wire tool to cut off a slab of clay and weigh it on a scale.

Cut the clay.
I went for 5lbs of clay here.

   
Wedged clay

“Wedge” the Clay

Wedging clay is kind of like needing dough. Repeatedly push the clay into itself to remove any air bubbles.

There are different ways to wedge clay.
Wedging shapes the clay.
The method I used formed a ram's head.

   
Clay on the wheel

Put it on the Wheel

Make a ball with the clay and smack it down onto the wheel as close to the center as possible.

Clay on the Wheel
The blue thing is called a bat. It attaches to the wheel head and lifts off when you are done.
I often shape my clay in a cone instead of a ball. It's personal preference.

   

Center the Clay

Centering the clay can be very difficult. Start by wetting the clay and your hands. Turn on the wheel at a fast rotation speed. Push from the top and the sides until the clay is perfectly centered on the turning wheel.

That doesn't sound so hard, does it?
This is what centered clay looks like.
The shape is controlled by how you push on it with your hands.

   
Pull the walls

“Pull” the Clay

Pulling clay is the method you use to raise the sides. Reach into the opening with your left hand, and support the outside of the clay with your right hand. Apply pressure to pinch the clay. In a controlled motion, pull the clay up.

Pull up the walls of the pot.
Pulling determines the height and shape of your pot
I'm not going to pull this very tall because I'm making a bowl.

   
Shape the walls

Shape the Form into a Bowl

Make controlled pulls that spread the clay outward at the top giving the pot the shape of a bowl.

Form a bowl
This particular bowl is shaped like a mixing bowl.
The number of shapes you can make is endless.

   
Tiles and cones

Dry Bowls & Load for Bisque

Once the bowl reaches leather hard, I trim the foot ring on the bottom by putting the bowl back on the wheel upside down. Then I let it totally air dry to a state called "bone dry". At this point I load all my bone dry pots into the kiln for their first firing.

I use multiple shelves in the kiln and stack pots on top of each other.
I place witness cones on the shelf to double check the firing temperature.

   
Tiles and cones

Bisque Fire

Once the kiln is loaded, I start the firing cycle. I must raise the temperature slowly so that the clay is not thermally shocked which can cause cracking. The bisque firing lasts about 9 - 10 hours for cone 04. Then the kiln must cool for 10 - 12 hours before opening.

Notice that the clay has turned pink after the bisque fire, and the cones bent over.

   
Tiles and cones

Unload the Bisque

The pots must be bisqued before glazing so that they are strong enough for handling. After the bisque they will still absorb water, and this is necessary for glazing to work. I sit the pots out on newspaper to get ready for glazing.

I have to carefully decide what glaze to use on each pot to compliment the form in color and character.

   
Tiles and cones

Wax the Foot

To prepare for glazing, the foot ring is waxed. This helps keep glaze from sticking to the foot. Because the silica in glaze is melted to a molten glass state during the glaze fire, no part of the pot that touches the kiln shelf can have glaze on it. If it does it will be permanently welded to the shelf after the firing.

I use orange colored wax so that I can see where I have painted it.
I apply wax carefully with a small brush.

   
Tiles and cones

Glaze & Load Glaze Fire

I dip the pots in a bucket of glaze to evenly coat them. The glaze is a suspension of powdered materials in water. Because the bisqued pots are porous, they absorb the water from the glaze. A delicate, powdery coating is left on the pots. I sponge off the feet to make sure there is no glaze on that surface, and load the pots in the kiln.

The pots cannot touch each other during glaze firing. The powdered glazes often look nothing like the glassy finishes they produce after firing.

   
Tiles and cones

Glaze Fire

The kiln reaches temperatures over 2200F during glaze firing. This causes the powdered glaze to transform into a strong, glassy coating. Inside, the clay vitrifies to a state where it will no longer absorb water. The glaze firing lasts about 10 hours for cone 6, and sometimes I do a controlled cool down by applying heat for an extra 4 hours. Then I must wait 10 - 12 hours to open the kiln.

It is very exciting to open the kiln and see the transformed pots glistening inside!

   
Tiles and cones

Finished Pot

Finally, the pot is complete. This process may take weeks from start to finish. And the pot shrinks about 10 - 12% from the wet state to the final glazed state.

This bowl is ready to serve food or decorate a table.

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