Sunday, March 12, 2006

Throwin' Large

Throwing starts by preparing the wheel. Our studio is a small room, and we keep the wheel pushed up against the wall when not in use. I pull it out a foot or so, and then set up my folding chair.

There are two holes drilled in the wheel head for batt pins. They are little bolts, with round heads, held on by wing nuts from underneath. I install a pair, and then place a masonite batt on by aligning the holes in the batt with the pins.

The two halves of the splash pan are on the counter, by the sink, where they were left to dry after the last cleanup. The larger of the two pieces slides under a fixture that is pierced by the shaft driving the wheel head. The smaller piece clips to it, to complete the circle.

The foot pedal is on the right, off to one side.

The water bucket is half filled with warm water. The wooden ribs get tossed into the bucket, two different sized kidneys, a squared corner with a point, a concave rib with a notch for conditioning the rim, and a small, dense rib that is shaped like a paisley. The smallest kidney sees the most use, followed by that notch in the concave. The paisley rib is the newest, least used and is so dense that it doesn't float. Its a blonde wood, instead of the dark woods of the other ribs. Two natural sponges join the bucket, a flat, thin, triangular sponge (a.k.a. "Sammy Sponge") and a stiffer, fat sponge from the shores of Florida's Gulf coast. I drop in a steel needle tool, as well.

Take out a fresh bag of clay, Standard Clay 266 (Chocolate Brown). Julie endulged me on Saturday, and we bought one hundred and fifty pounds of the stuff. It's an eight inch, plastic wrapped cube, the color of milk chocolate, and weighs twenty five pounds. Peel back the plastic bag, and invert it onto the wheel head. The moist clay smells musty and moldy.

Ah...freshly squeezed.

The cube needs to become a bowl. If I was throwing a mug, I would cut off a piece, form it into a ball, then place it on the wheel.

I have bigger plans.

Some potters slap the clay into shape with the palms of their hands. While effective, in the long term the repeated blows can cause bone spurs to form in your hands. We manipulate the clay against the wheel head to achieve the same results.

Pick up the cube of clay. Rotate it so that one of the corners where two faces of the cube face the wheel head, then 'bounce' the clay off of the wheel. This flattens the corner. Repeat three more times, and we have a piece of clay that has an octagonal cross section, and a more or less flat top and bottom.

The sides have smushed down a bit, past the bottom face of the clay. If we slap it to the wheel head, an air pocket will be trapped, which will cause problems in throwing and trimming. There is this motion that I do with the clay, to push the bottom face back into shape. Think of the final moments of a spinning coin, when the coin is wobbling nearly flat at high speed, where one point on the edge is touching, the touching point circling the center of the coin. This is the motion the clay must take. Pick up the clay, and nutate the lower edge on the wheel head. This bevels the lower edge.

Its now a 'ball'.

Slap the clay down, in approximately the center of the wheel. There is a lot of friction between a hand and the moist clay, so grab a sponge full of water, and squeeze it over the top.

Place the right foot on the pedal. Make sure it is in the off position. Switch on the wheel.

My legs are spread around the splash pan. My left foot should be flat on the ground, but I tend to hook it around the left front leg of the chair. My left upper arm is locked against the side of my ribs, with my left elbow touching the top of my pelvis. My forearm is strait, and the edge of the hand rides the wheel head, and the clay meets the base of my palm.

I apply power, and the clay starts to turn.

Centering the clay requires that the left hand be held still. It bounces against the mishappen clay. My right hand is on top of the clay, near the left, at the seven o'clock position. I stiffen my hands, and lean my body in, and let my weight force the clay to change shape. The trick to centering is to judged the size of the bounces, then slowly reduce their amplitude with your hands, to force the clay to take a new shape.

The bouncing subsides, and smooths out. The base of the side becomes cylidrical. I shift my left hand up a bit, to center higher on the piece, and lock thumbs with my right hand. Leaning in, again, and the piece centers.

I lean back, reducing the forces on the piece, then gently remove my hands. The clay looks like a cake with milk chocolate icing. Rewetting my hands, and assuming the position, I flatten out the cake a bit, by pushing down on the top with my right, while supporting the side of the piece with my left. Shortening the cake increases its diameter. I stop when the cake is about a foot across.

Left hand rides the side of the cake, right hand rides on top. Thumbs are hooked togeather. Using the left hand to steady the right, I place my index finger into the exact center of the rotating cake, and gently push down. A dimple forms, about a half inch deep. My fingertips start to bind with the clay, so I back off pressure, and remove my hands. A sponge is used to put some water into the dimple.

The wheel is slowed down a bit.

Rewetting my hands, I reposition them on the top and side of the cake, and puch downwards into the soft clay with my right fingertips. The clay is soft, I curve my fingers down into the hole to help make it symetrical as it grows deeper. I stop when I get within about an inch of the wheel head. I rewet my hands. Starting from the point on the hole closest to me, run a fingertip strait down to make sure that the hole is perfectly circular, and exactly centered in the cake. If it is uneven, it can be fixed in later steps, but the uneven wall thickness will turn into, at best, an uneven height around the rim, which will be trimmed down. Most pieces have to have the rim trimmed a little, to even it out and make it the same height all the way around.

The wheel is slowed down a bit.

The right fingers are hooked down the center hole, the arm is locked, and I lean back to pull the center hole larger, until it is a few inches in radius. I hold my hand steady for a few revolutions of the wheel, to ensure that the wall is even all the way around.

The wheel is slowed down a bit.

Rewet the hands, then wet two sponges. Grasp a sponge in the palm of each hand, and form loose fists, with the forefinger wrapped over the tip of the thumb. The left hand goes down the center of the piece, forearm straight up, and the right is on the outside of the piece. Both
hands are at four thirty, the second digit of the forefingers facing each other. Gently squeezing the clay between the hands, pull steadily upwards and slightly outwards. The speed of pulling is related to the speed of rotation; a full rotation needs to take place before the hands move more than the thickness of a finger. The distance between the hands is defining the thickness of the walls of the piece. They need to stay thick for now. As the fingers start to bind in the clay, a gentle squeeze on the sponges remoistens the surface. When we approach the top of the wall, we back off pressure a little.

The wheel is slowed down a bit.

The piece recieves several more pulls. Each pull increases the height of the piece. Each pull increases the diameter of the piece. As the piece gets wider, the wheel speed must be reduced so that the clay does not travel through the fingers too fast, or start to bind and stretch. As the bowl starts taking shape, care must be taken to leave sufficient clay in the base of the walls to support the flaring walls above them.

Once an approximate bowl shape is achieved, the wheel is slowed down a bit. The small kidney rib is pulled out, and, held in both hands, its curved surface is used to finish the floor of the bowl. Excess clay is scraped off the rib, into the bucket, as necessary. Shifting the rib to the left hand, and a sponge in the right, the edge of the rib is used to perform a pull on the piece, where the sponge is on the outside in the right hand. This smooths out the inner walls of the bowl.

The outside of the bowl can be conditioned using the concave rib in the right hand on the outside of the bowl, with the left hand gripping a sponge supporting the inside of the bowl. I like to leave the throwing marks, ridges, and lines on the outside of some bowls.

The bowl is slowed down a bit. It turns very slowly now, taking several seconds for a single revolution.

If required, the rim is trimmed with the needle tool. A wet left hand rides the rim, supporting the inside and outside walls. The needle tool is gripped with the right hand, the needle is rested on the left thumb with the tip tangent to the bowl. The needletool is slowly rotated against the thumb through the wall of the piece, until it makes contact with the left pointer finger. Once the clay has detached from the piece (like, it starts to fall off), the scrap is removed by raising both hands simultaneously, high enough to lift the scrap clear of the rim. Throwing nirvana is reached when no trimming is required; the centering, opening, and pulling of the piece all came together to make a perfectly flat rim.

Wetting the notch in the concave rib, I condition the rim of the bowl. Wetting the left hand, I support the walls of the rim with thumb and forefinger. The right hand brings the notch down onto the top of the rim, and the notch is slowly repositioned several times to allow it to round off the rim for the entire circumfrance.

A notched tool is used to cut away a little bit of clay at the base, and a cutting wire is run under the piece.

The finished piece should measuer at least nine inches tall, and at least eighteen inches accross. It would look something like like this:
Nirvana was achieved when throwing this piece; note the lack of rim trimmings to the left of the splash pan next to the water bucket.

This piece was followed by the throwing of four Brooklyn Red mugs, and I trimmed my half-bag bowl thrown from 306.


Blogger Maureen McHugh said...

Ah, zen and the pottery wheel.

Congrats on the beautiful bowl.

6:52 PM  

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