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Using a Throwing Stick

Using a Throwing Stick

Perhaps you´ve seen these gizmos called throwing sticks. There is a photo at the bottom of this page in case you haven´t. Learned from my friend Ben Ryterband at Mass. College of Art. The stick takes the place of the left hand (if you throw counterclockwise) on the inside of the form. Strategy used with throwing sticks is also useful in throwing forms you CAN reach into.

If you make a bottle-ish form without a stick, you pretty much HAVE to form the lower part before you "neck it in" because you can´t go back an change it when the neck is too small to reach into. You can move the lower wall clay inward by pushing from the outside....... but not move it outward. Possible....but HARD.

I am sure that you have noticed that certain shapes of clay on the wheel tend to collapse easier than others. Physics in action.

So you pull a cylinder. Then you lightly bulge the middle just a tad. Then you start to narrow in the neck. You rough out the neck area pretty close to the finished diameter. Then you finish the shoulder curve and finally the neck details. Then the foot area. Bingo.

The stick can be used both to compress and move clay....or to simple stretch from the inside. The use of the stick (also called an egote in Japanese) allows this change of approach.

It takes some getting used to. You have to have FULL control of the stick, and learn to read sensation through it. Don´t expect to master it overnight. I find that for most uses that you want the fingers of the left hand to wrap around it like you were grasping a pole to steady yourself on a subway or trying to hold a live ant in your hand until you could get it outside.... For me the KEY is the thumb position. It shouldn´t be wrapped over your other fingers like a fist. This is the power and the sensitivity all at once in using an egote.

Centering

Centering the clay

The theory of centering is simple. A lump of malleable material (clay) is placed on a revolving surface (wheel head), forced into a symmetrical form by contact with a fixed object (the hands), and lubricated to reduce friction..........

Read this entire article ´Centering the clay´ in the Articles section on this site
Or go to:
http://www.ceramics-tips.com/RscArticleV.asp?id=389

A how-to overview

The evolution of a pot
What are the steps from your hand to finished piece?

It begins with clay. Many potters today use pre-mixed clay which is added to water and left to age in large bins or we can purchase it pre-made weighed out in 25 pound bags.

First, wedge your clay thoroughly, 40-50 kneading
motions for a 6-8 pound lump of clay should yield good clay for throwing. When your clay is properly wedged and you have checked for air bubbles by cutting a cross-section to see if any air is trapped inside the clay body, you can affix it to the wheel head........

Read this entire article ´The evolution of a pot´ in the Article section on this site
Or go to:
http://www.ceramics-tips.com/RscArticleV.asp?id=388

Clockwise or anti-clockwise wheel

Most potters learn to throw anti-clockwise and if a power wheel is used it is unlikely to be reversible. However, some experience with throwing clockwise is beneficial because it makes one analyse one´s actions thoroughly. Also some clays, notably those containing only a small amount of naturally plastic clay, eg, special bodies like porcelain, sometimes tire of being turned one way only. Some tear if the leatherhard trimming (turning) is done with the same wheel direction as the throwing. In such cases throwing is done anti-clockwise and turning is done clockwise. Also after throwing many potters reverse the wheel direction and burnish the leatherhard clay surface.

Avoiding s cracks

Have you ever had trouble with cracks developing in the base of your wheel thrown work? This problem can be avoided by following a few simple guidelines.
Cracks develop for two main reasons: uneven drying and uneven compression in the throwing process.
 Avoid uneven drying
OK, so you put your wheel thrown work in a drying cupboard. You even additionally cover the work with plastic sheeting, trying to ensure even drying. But if you are throwing on a bat, no air reaches the bottom of a platter, vessel or other thrown object. What happens? The top dries a bit slower. As the top dries, it shrinks and pulls together, cracking the slightly wetter and therefor larger surface at the bottom. Once a crack has developed, it is near to impossible to get rid of, even by turning (trimming). One way to avoid this might be to turn over the work halfway in between the drying process, but this is not usually feasible. So what to do? How to get that bottom drying at a similar rate? The answer: throw your work on plaster bats. (How to make plaster bats will be the topic of a feature soon to come.)
The bat will need to be moistened, otherwise the clay will pop off too soon and throwing will become an impossibility. After throwing your work, the piece can be lifted off while still on the bat, and the bat, work and all, can be placed in your normal drying area. After a few hours, depending on moisture content of the bat, the work will pop off all by itself, and may even be ready for turning that same day.
 Avoid uneven compression when wheel throwing
Cracks may not appear until in the firing itself, often even until a second high temperature firing, especially in fine clays like porcelain or porcelaineous stoneware. Rougher clays like raku are generally not so prone to cracking, unless you really treat them badly, as the grog tends to absorb a lot of tension. For finer clays, the best technique to get a consistently compressed clay throughout is to center the clay on the wheelhead, then cut off the clay with a cutting wire. Invert the clay and recenter ´upside down´. This ensures that the clay will be quite compressed at the bottom as well as at the top.
Combined, these two techniques should be able to cure most cracking problems with wheel thrown work

Protecting rims

Another use for a mouse pad is to protect the rim of a piece when you turn it upside down to trim, attach feet, etc. Resting a piece on its rim can weaken it. Even if you don´t notice a crack, one might occur during firing.

Prevent trimming pinholes

Glaze pinholes often form in areas that have been trimmed, as trimming tends to open holes in the surface. To prevent, slightly burnish the trimmed area with a stone or spoon, while still on the wheel, or rub the slip from throwing over the area to fill the holes.

Defining the rim

Completing the form

When a successful form is pulled, it is completed with
refinements of the lip (also called the rim) and removal from the wheel head. During both of these activities, speed of rotation varies according to the stability of each shape thrown - greater stability allows faster rotation. Horizontal ware, such as bowls, will require a considerably slower speed. Fifty rpm is a starting point to experiment with for
slow rim refinement.

Refining the rim

Once the shape of the rim is defined, it is finished with a wet chamois, a wet sponge, or a lubricated finger. The finishing action leaves a smooth clay surface and may also make subtle adjustments in lip thickness and shape. Uniform lubrication is important for maintaining a centered rim during finishing.

How to attach a bat to the wheelhead

To attach bat to the wheelhead, you must throw a small
ball of clay, flatten it out to cover at least 15cm of
the wheelhead Create two grooves in the disc of clay,
then create a channel from the centre of the disc to the
outside,( this will drain excess water and stop the
bat bed from becoming too moist). The wooden bat can
now be centred on the clay disc, and ware thrown and
removed on the bat.

Introduction

Wheel throwing with standard clay. Again, a kiln is required. And once you are an experienced thrower you will undoubtedly want a large kiln, since you will produce pieces much more quickly than in hand-building. However, at the beginning I would recommend joining a class if at all possible. You can learn to throw from books or even better, videotapes, and some people do. But it is difficult. It takes a while to get the knack for throwing, and can therefore get frustrating unless you have interaction with an instructor and see other students struggling as you are. I think most people with no experience, buying a wheel and trying it out on their own, would get frustrated and give up. A class will offer you instruction, a kiln, and glazes so you don't have to worry about that quite yet. Your only investment will be the cost of the class, and perhaps some materials costs such as clay and a basic tool set for under $20. At some point you may find that you don't like to be constrained by the hours of the class, that you want complete control over your work (so someone else doesn't smudge the glaze, break, damage or steal your pieces), or that you want to do things beyond the capability of our class studio. At this point I would recommend getting your own wheel, and kiln unless you have access to someone else's kiln. However, if you are patient, you could continue to build your throwing skills, never firing anything but instead recycling the clay to be thrown again. It is tempting to want to finish each piece at the beginning, because you are very proud of it, but soon you will hate the look of those early pieces! so not even firing them at all would be a fine strategy. While you are in the intermediate stage, assuming you are firing your work, I would recommend an extruder. The reason is that you can make use of the hundreds of small cylinders you will throw, by putting nice handles on them and making mugs. Otherwise practice making hand pulled handles (shown in most pottery technique books.)

Making Holes

If you make holes for a strainer, try using a drill. This is much faster than doing it by hand. A cordless drill is handy, as you don´t have to worry about electrical cables or plugging it in.

Pulling the clay

Basic Throwing -

Pulling the clay

You are ready to pull the wall if the outside of the hump is
centered and the clay is opened in center. As your skill increases, it will become apparent that pulling can also have a centering function - many professionals use this technique. But as beginners, it will be important to pull from a well centered and opened form. If the opened hump is off center, the probable causes are either insufficient hand tension, allowing the rotating cylinder superior force, or
releasing pressure too quickly.

Pulling has three main purposes: thinning the wall, extending the form, and directing the shape.

Note: If further spreading of the bottom is needed, the indentation is made prior to pulling. The lowest portion of the wall is squeezed between a surface on the inside and another on the outside of the wall. This helps trim away excess clay which spreads out at the base of the wall by a method similar to the undercut described earlier, besides defining the base of the walls visually it helps the fingers in raising the clay up from the bottom of the pot.

Thinning the wall

Thinning the wall
The wall is thinned by squeezing the clay between a
surface of each hand and moving the hands (and thus the lay) upward while squeezing. You can pull clay from the outside, inside, or both sides of the clay wall, but pulling from both sides produces the best results. Customarily, the distance between your hands remains constant throughout each pull............

Read this entire article ´Thinning the wall´
in the Articles section of this site
Or go to:
http://www.ceramics-tips.com/RscArticleV.asp?id=396

Opening up

Hints for successful openings

* Opening is performed at the same wheel speed used for centering, and it also involves the tensing of opposing sets of muscles when pressure is applied. The pressure used to open the clay should be sure and even, and the downward movement should be direct, smooth, and relatively fast........

Read this entire article ´Opening the clay´ in the Articles section of this site
Or go to:
http://www.ceramics-tips.com/RscArticleV.asp?id=394

A good teapot

To see whether a teapot is good or not, one of the many indicators is flipping the teapot over and see whether the mouth of the sprout, the opening on the body and the handle are at the same height, thus the teapot should be able to stand firmly on the table upside down. However, this rule does not apply on some teapot shapes that are unusual. It applies to most conventional shapes though.

Prevent losing your Chamois

Lose your Chamois in your bucket of throwing water?

Stick a corner into an empty film canister, close the lid, and it will float. Or tie the chamois to a 1” fishing bobber.

avoiding cracks through uneven drying

Have you ever had trouble with cracks developing in the base of your wheel thrown work? This problem can be avoided by following a few simple guidelines.

Cracks develop for two main reasons: uneven drying and uneven compression in the throwing process.

Avoid uneven drying
OK, so you put your wheel thrown work in a drying cupboard. You even additionally cover the work with plastic sheeting, trying to ensure even drying. But if you are throwing on a bat, no air reaches the bottom of a platter, vessel or other thrown object. What happens? The top dries a bit slower. As the top dries, it shrinks and pulls together, cracking the slightly wetter and therefor larger surface at the bottom. Once a crack has developed, it is near to impossible to get rid of, even by turning (trimming). One way to avoid this might be to turn over the work halfway in between the drying process, but this is not usually feasible. So what to do? How to get that bottom drying at a similar rate? The answer: throw your work on plaster bats. (How to make plaster bats will be the topic of a feature soon to come.)

The bat will need to be moistened, otherwise the clay will pop off too soon and throwing will become an impossibility. After throwing your work, the piece can be lifted off while still on the bat, and the bat, work and all, can be placed in your normal drying area. After a few hours, depending on moisture content of the bat, the work will pop off all by itself, and may even be ready for turning that same day.

Avoid uneven compression when wheel throwing
Cracks may not appear until in the firing itself, often even until a second high temperature firing, especially in fine clays like porcelain or porcelaineous stoneware. Rougher clays like raku are generally not so prone to cracking, unless you really treat them badly, as the grog tends to absorb a lot of tension. For finer clays, the best technique to get a consistently compressed clay throughout is to center the clay on the wheelhead, then cut off the clay with a cutting wire. Invert the clay and recenter ´upside down´. This ensures that the clay will be quite compressed at the bottom as well as at the top.

Combined, these two techniques should be able to cure most cracking problems with wheel thrown work.