Recycling Clay Archives - Seven Limes Pottery

What is wedging?

Wedging

Wedging is the process of making clay into a homogenous consistency through kneading, cutting, and slamming the clay down. It aligns the clay particles, evens out lumps and moisture levels, and removes air pockets.

The process of wedging is used to prepare clay before use. It’s a good idea to wedge the clay even if it’s straight out of a fresh clay bag from your supplier.

Wedging vs Kneading clay

Traditionally, wedging, referred to a process separate from kneading, with kneading being a process of folding a mass that can be done with clay and other mediums such as bread dough. Wedging is cutting a piece of clay in half (a wedge), picking the half up and slamming it back down on the other half. This process is unique to clay, necessitating it’s own word, and by itself it can homogenise the clay and remove air pockets. To process clay, wedging is combined with kneading, both of which homogenise and removes air pockets.

With the spread of social media, and the dilution of formal education in ceramics, the meaning of the word wedging has changed over time. It’s meaning more commonly encapsulates both kneading clay as well as the process that is more traditionally known as wedging. Wedging is now often used to refer to kneading alone as well. If you have any references for the origin of word wedging we’d love to hear from you.

Spiral Wedging/kneading

There are 3 Types of Wedging

Spiral Wedging

Spiral wedging is a technique to knead clay. It folds layers into the clay by rocking it forwards and backwards and rotating it in a spiral motion, at the same time. It’s the more advanced form of wedging and can take a little while to learn to proficiency. The clay ends up looking a little like a snail shell

Rams Head Wedging

Rams Head wedging is easier to learn the spiral kneading. In Rams head wedging the clay is kneaded by rocking it back and forth each time folding the clay back into itself by pressing with each hand on the left and right hand side of a log or roll of clay.

Cut Wedging

Cut wedging is where the clay is cut horizontally with a wire, the top wedge of clay is picked up, and then it’s slammed down on top of the other piece of clay. The wedge is usually turned before being slammed down, and once stacked the clay block is also usually picked up and turned, so that the wire then cuts through a different part of the clay. Different potters may use differing methods of cut wedging, for example the clay can be cut at an angle or it can be cut straight.

Cut Wedging

Sam Andrew

Sam Andrew is a ceramicist creating Nerikomi tableware and ceramic art pieces focusing on material reuse, pattern and perception. With a background in Clinical Neuropsychology Sam learned ceramics since a young age and changed career a decade ago to design and make ceramics.

How to Recycle Clay

Is clay recyclable?/ Can you recycle clay?

Yes, clay is infinitely reusable and recyclable, if done well it is a process that will save on the costs of purchasing new clay, and keep you fit along the way. It’s only once the clay is fired that it is more difficult to recycle. So, how do you recycle clay?

How to recycle clay: Divide The Clay Into Different Levels Of Dryness

To recycle clay it is useful to divide the clay into different moisture levels, we do it in 4 levels:

Hard and Dry clay, that is no longer plastic or flexible.
Soft Clay, like you would get out of a bag or from off-cuts.
Wet Clay, which is soft clay with water on it.
Clay Slops, such as the thickened clay water that collects during wheel throwing.

We treat each moisture level of clay differently, by dividing them in this way can reduce the amount of work involved in the clay recycling process. We keep buckets in the studio for clay slops, wet clay and dry clay, and finally then soft clay can be put straight back in a bag or kneaded right away.

Hard/Dry Clay

Hard and dry clay, that is no longer plastic or flexible, should be collected and left to fully dry out to the bone dry stage. This includes trimmings from turning, failed pots that are leather hard or bone dry, off-cuts from hard slabs, and shavings/debris from other hand-building processes.

Soft Clay

Soft clay, even if it’s dried a little, as long as it’s still plastic and flexible, can be kneaded into a clay block and reused right away. It does not need to go through the whole recycling process. Soft clay can include off-cuts from soft slabs, trimmings from soft clay pots, and clay lumps used to pin down thrown pots for turning.

Wet Clay

We put flopped pots from throwing on the wheel, if there are many, in their own bucket. Wet clay such as from pots flopping over on the potter’s wheel or pulling handles, as with soft clay, can also sometimes be kneaded into a firmer block of clay and be reused right away. However, when the quantity is too much or the clay too wet, it may stick to the kneading surface, making the process difficult. In this case it should be collected and left to dry out. This clay does not need to go through the whole recycling process either, it just needs to dry a little until firm enough to knead into a block.

Clay Slops

The thickened clay water that builds up while wheel throwing we call slops. It should be collected separately in a bucket. As this settles over a day or two the water can be pared off of the top of the bucket.

The Clay Recycling Process: Step by step

After dividing the clay into different moisture levels, the steps to recycle clay are:

1. Slake down the clay

Add the clay slops to the fully dried (bone dry) waste clay. Depending on the size of the clay pieces, soaking the dry clay will slake it down to a thick slurry in 1 day to 1 week. If it’s fine trimmings from turning, they can slake down quicker.

Dry clay slaking down during clay recycling process

2. Put the clay slurry out to dry

The clay is given a good mix and put out to dry on plaster batts. The air and plaster together will help dry the clay. It’s dry enough when it won’t stick to a wooden board when it touches one, so it can be wedged. If left for too long the clay may be too firm to knead. It can take a couple of days to a couple of weeks to dry depending on how thinly it is spread, the weather, whether the kilns have been on, and the absorbency of the plaster batts.

3. Knead the clay

Once dry enough, it’ll be soft enough to knead. The clay is simply kneaded and wedged until it becomes a homogenous consistency. Kneading mixes in any harder lumps, and also removes air pockets. It’s then ready to throw and hand-build with.

What is Wedging?

Wedging is the process of kneading clay to make it into a homogenous consistency. Wedging does this by mixing and aligning the clay particles, and removing air pockets during the process. Read more on wedging.

Recycling clay

Recycling clay is an effortful process initially. When done inefficiently it may even be cheaper to sling your waste clay down a hill and buy some new bags of clay. However, how you recycle clay, by dividing the clay into different moisture levels, understanding when to do each stage of the recycling process, and your skill in wedging has progressed: it is something that is economically beneficial, helps keep you physically active encouraging good health, and is better for the environment. It’s a necessary step for any pottery studio especially community studios like ours that offer pottery classes.

Sam Andrew