Choose the right clay

Image of clay bodies. Courtesie of The Ceramics Shop.

When starting with pottery, you are facing many decisions, in particular which clay you should use. Although you should explore using different type of clays and find the one that suits best your needs, we will explain below how to choose the type of clay to start with to save your time and avoid mistakes.

Working from home

For situations where a kiln is not available, when working from home for instance, you will choose an air drying clay, which will be strong and plastic, due to its super fine particles. Some air drying clay bodies contain fibres such as nylon to reinforce their strength. The clay can be decorated with acrylic paints and clear varnish. The varnish can seal the pot and make it waterproof, but the piece won’t be food safe. Some air drying clays can also be fired.

You can purchase air-drying clay from the list of suppliers in our Directory page. Clay is often sold in bags of 12.5 Kg, but these suppliers are offering air-drying clay in smaller quantities:

Note that the dry clay colour varies from white to grey or red. If you paint the piece, the underlying colour is not so important and the grey option which is cheaper may be recommended. Otherwise, choose the white clay.

Working in a pottery studio or with access to a pottery kiln

If you have access to a pottery kiln to fire your pieces, usually found in a pottery studio, there are more clay bodies to choose from, which makes the decision on which one to use quite difficult for inexperienced potters.

If you are working in a pottery studio, you are likely to be offered few clay options to purchase. The choice will depend on the type of pieces you want to make, the firing temperature, the colour and aspect of the clay once fired and the technique involved for the making (hand building, throwing, slip casting, etc).

For a beginner pottery class, the studio will provide you probably two or three types of clay to start with, usually an economy one such as a red or white earthenware (low firing) or stoneware (high firing) clay.

As you will start hand building pots, you should use a clay containing grog, a sand-like substance that is added to a clay body to add workability and strength to the clay. Finer, more plastic clay should be reserved for throwing.

Once you progress in doing pottery, you may decide to use specialised clay such as black or crank stoneware, porcelain, or paper clay to achieve specific goals.

To find where to buy your clay in the UK, please visit our directory page.

The following table will guide you in your choice:

UsageTechniqueClay typeComments
Domestic and culinary pots, bricks, tiles, roof tiles, garden pots, sculpturesHand-built, thrownRed (terracotta) or white earthenwareEarthenware was largely used for peasant pottery. Usually fired at 1,000 – 1080 oC. Good resistance to thermal shock. The body porosity allows for evaporation through the surface. Green pots may be prone to frost damage. Terracotta clay is one of the cheapest option.
Domestic and table ware (functional pottery like pitchers, plates, bowls and dishes), decorative pieces, pieces for outdoor useHand-built, thrown, slip-castWhite and coloured stoneware, standard, buff or grogged.Stoneware usually fires at 1,200 – 1,300 oC giving a hard, smooth finish, with the particles of clay being fused and the pieces impervious to water. The addition of grog (small pieces of fired clay) increase its strength and the resistance to wrapping. Clay bodies can be coloured with oxides additions (red, black, etc.).
Domestic and table ware, decorative pieces.Hand-built, thrownPorcelainPorcelain is usually fired at temperature in excess of 1,280 oC. It’s a very white and dense material, with incredible strength and extreme durability. However porcelain clay bodies are the least plastic and the most difficult to throw and hand-build.
Large scale work, sculpture, delicate decorative piecesHand-buildPaper clayPaper clay fires at different temperatures depending on the underlying clay body used. The addition of cellulose fibres to a clay body, stoneware or porcelain, give strength to the pieces allowing to build large-scale works extremely strong and a fraction of the weight of regular clay. Paper clay has the ability to stick to itself in any state: wet or dry, thick or thin. When fired, the fibres burn away, leaving multitude of holes through the clay body, thereby reducing its weight.
Decorative pieces, large tiles, slab pottery and large-scale sculptural workHand-build, thrownRaky clayRaku clay fires between 800 and 1,000 oC. As the process involves removing the pots red hot from the kiln and cooling them rapidly, the clay must have a coarse, open texture in order to survive to the thermal shocks (extreme expansion and contraction).
Decorative pieces with no firing requiredHand-buildAir-drying clayAir-drying clay doesn’t require firing, although some clays may be fired up to 1,200 oC. The super fine particle size allows model makers to produce very detailed forms. The air-drying clay can be decorated with acrylic paints and clear varnish.
How to choose a clay body depending on the usage

Visit our Directory page to find a pottery studio near you or our Resources section to find online courses and workshops.

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