THE most important thing when dealing with any aspect of clay is preparation. Without this, the clay won’t handle properly, and you run the risk of trapping air in the body of the clay, which will cause your work to explode when it’s fired
Re-claimed clay requires storage for at least a few weeks to restore plasticity, but the longer it is stored the better it will be. Keep it in sealed plastic bags and label the bags with dates and clay type. Store in a cool but dry place until ready to use
One of the many great things about working with clay is that there’s very little wastage, because until it’s fired it can be re-processed over and over again without detriment. As you work you will generate scrapings and off cuts, all of which, with a little preparation, can be re-claimed, along with unsuccessful pots (providing they have not been fired).
The following process for reclaiming clay demonstrates the best method to use for those starting out with minimum equipment and space to work in.
The tips below suggest ways to speed up the process and improve your working practice – all very easy, although a little messy!
If working with more than one clay type, you can reclaim each type in individual buckets or save them together in one to make a mixed body – this is common practice in schools and colleges, where technicians don’t have the time to sort out the different clays. If choosing this option, make sure you test the mixed clay body before making a piece of work, because the working and firing properties of the clay can change slightly in the mixing.
• Make sure the clay is completely dry before re-claiming – if not, the clay will not slake down properly.
• Using warm or hot water will speed the slaking process up considerably.
• Re-claim in small batches to keep on top of things, otherwise you end up with great bins of clay that seem too daunting to deal with.
• Make up some plaster batts especially for the job – they are by far the most absorbent surfaces, but failing that look for absorbent board in your DIY store – some fibre boards work really well.
• A wheelbarrow can be very useful for processing larger amounts. Drill several holes in the base of the barrow and line with heavy-duty fabric – old jeans are great for the job but sacks or hessian work well.
Site the barrow outside and fill with clay slurry – the excess water will drain away and the clay will firm up in the sun until ready to wedge.
Allow the clay to dry out completely, then break it down into small pieces and place it in a plastic container – washing up bowls are a good choice because they contain a manageable amount. Cover the clay with warm water and allow it to break down overnight – this process is called slaking down. The water should completely cover the clay.
Siphon off the excess water covering the clay. The easiest way to do this is to use a slip trailer, but any soft squeezy bottle would work if you don’t have a trailer. Empty the excess water into a separate container close to the clay, to minimise spillage.
Give the slurry a little mix then transfer to an absorbent surface, such as a plaster batt, to form a layer about 5cm thick. Use your hand or a wooden spoon for this – either way it can be a little messy.
The clay will dry out quite quickly so check it from time to time. When it has dried to a stage where it can be lifted easily from the batt, turn the clay over so that the wetter surface comes into contact with the plaster, to even up the firming process.
When the clay has firmed up to a workable consistency roll it up as shown, so that any remaining excess moisture is contained – this will be distributed when the clay is wedged.
Still working on the plaster batt – work the clay into a large brick shape – this is by far the easiest shape to manage when wedging.
Wedging is an essential process, for several reasons, but most basically to mix the clay thoroughly and remove air bubbles that can cause the constructed form to explode or shatter when fired if not removed. It’s the next step in the re-claiming process and the first exercise of preparation before using the clay, whichever making method is to be used.
Tip before starting
Wedge your clay on a sturdy work bench which is just below waist height, because the process involves a lot of force and this will allow the clay to fall from a greater height – thus enabling you to use less force and save energy. It’s helpful if the workbench surface has some degree of absorbency, but you can transfer the plaster batt, to the workbench to continue the process if not.
Lift the reclaimed brick of clay in one hand then allow the front end to fall onto the workbench so that the back end remains raised slightly.
Position the cutting wire under the raised end of the clay mass as close to the centre as possible and cut it in half by drawing the wire upwards.
Lift the front half of the brick and turn it, so that when placed on top of the other half the two cut faces will be the same way around.
Now raise the top piece of clay to shoulder height then throw it back down on top of the other half forcibly, allowing the weight of the clay to do the work for you. Neaten the clay mass back to the original brick shape by beating it with your hand, then repeat the process until the two clays are completely combined. It will take some time, and probably involve at least 20 ‘cut and lifts’ but keeping control of the shape will make the job faster and easier. The clay is ready for use when it has an even consistency and colour, and is air-free.
Clay preparation is vitally important for successful potting, and kneading is helpful to even-out the clay body and remove any air bubbles left behind after wedging. However, this said, properly wedged clay will need only minimal kneading so it’s worth perfecting the technique to save time and effort at this stage.
Water is constantly evaporating from clay, making it appear wet around the edges but much drier in the middle. Kneading the clay re-distributes the water, but the evaporation process will start again almost immediately, so a good tip is to only prepare enough clay to complete the project you are working on, and keep it sealed in plastic at all times until required.
Generally, this process is performed immediately prior to starting work, and it should become an integral part of your working practice.
This method is obviously named after the shape that’s formed as the clay is kneaded – many potters find it the easier of the two methods demonstrated.
Position your hands on opposite sides of the clay mass with the heels of the hand over the top, and the fingers wrapped around the sides, as if to contain them. Push the clay down and away from the body, digging the palms into the clay so that a raised mass remains in the centre. Roll the clay back towards the body and reposition the hands slightly forward on the clay. Repeat the rolling and pushing action, trying not to fold the clay because this will re-introduce air into the body, which will defeat the object of the exercise.
As you knead the clay, the ox-head shape will develop with the hands forming the eye sockets.
Continue to knead the clay by rocking and pushing until it’s smooth and thoroughly mixed, with no air pockets. Cut through the kneaded clay from time to time to check progress.
A spiral shape is formed as the clay is processed using this technique. It’s more difficult to master than ox-head kneading, but is useful for larger amounts of clay.
Place your hands on opposite sides of a roughly rounded mass of clay. Use your right hand to push down on the clay, while rolling it forward, and use your left hand to contain the clay from the side and prevent sideways movement. Use your left hand to also rotate the clay mass after each forward movement. This action creates the spiral. Use the weight of your upper body rather than your wrist to perform this type of kneading, to keep control of the shape.
You will see the spiral begin to develop as you knead, but a cut through the clay mass from time to time will better show the developing spiral and whether or not you’re performing the process correctly.
Continue to rotate the clay counter-clockwise, moving the right hand into position for each downward push. You should try to develop a rhythm as you work, to make the job easier. The clay is ready when the clays are thoroughly mixed and smooth, and there are no air pockets.