The Different Types of Clay Used for Handcrafted Pottery

The Foundation of Pottery – The Clay

At KLT Designs, the choice of clay body is fundamental to our craft. The underlying clay body impacts everything, from the ability to create a form, to the colour of the finished glazes. If you’ve ever wondered what the most popular types of clay used in our pottery are, look no further. In this post we go over the two clay bodies used most frequently in our studio and how they shape our work. 

 

What is a Clay Body?

A clay body is a blend of clays and other minerals that hold particular working properties and fired characteristics. If you were to dig a lump of clay out of the ground, make a pot and fire it, it’s unlikely you would achieve your desired end result. This is because the composition of the clay body determines its strength, firing behaviour, colour, texture, glaze compatibility, among other things. 

From a basic standpoint, clay bodies can be Earthenware (low-fire), Stoneware (mid-to-high-fire) or Porcelain (high-fire). Earthenware is typically weaker and more porous (lots of holes). Porcelain, however, typically produces maximum whiteness and translucency (you can see through it). 

Stoneware is what we use at Katie L Thompson Designs. It’s more durable and chip-resistant than Earthenware but less brittle than Porcelain. It’s suitable for both functional and decorative pieces. Unlike Earthenware, Stoneware becomes non-porous when fired so it can hold liquids. 

 

Stoneware Clay Examples - Classic Collection

Our Classic Collection is created from Valentine’s B17C Stoneware Clay. It’s a very smooth clay body that fires a pale buff. This creates an ideal background for our glazes as there’s very little interaction between the minerals in the clay body and the glazes. 

The insides of our mugs and jugs are glazed with a transparent glaze, allowing the neutral clay body to shine through. Our Carved Collection also emphasises the raw pale buff clay contrasting against the black underglaze.

One of our stoneware examples include the Alpine Green Mini Jug.   

Rustic Collection

Our Rustic Collection is created from Valentine’s Delta Stoneware Clay. Its toasted colour, flecked with iron, evokes a sense of warmth and connection to the earth. 

The interplay between clay and glaze opens up a new world of possibilities for creating unique, organic-looking pieces. The rustic, earthy look lends itself to greens, blues and neutral tones. 

A transparent glaze allows the toasted clay body to shine through on our mugs and jugs. Our Carved Collection also emphasises the raw toasted clay.

Sometimes we like the effect both clay bodies have on our glazes, as can be seen from the Nebula Blue Collection. Other times, the combination doesn’t work on both clay bodies.

A good example of Delta stoneware can be found in our Nebula Blue Rustic Mug. For B17C clay, an example would be our Nebula Blue Classic Mug, which is smoother in texture and has a softer gradient. 

 

Clay Working Properties

Both clay bodies used in our studio are designed for wheel throwing. We opted for clay bodies with very little grog (a granular additive) as this can be painful to work with when the wheel is spinning quickly. Grog is often used in sculptural work or for larger pieces as it adds strength and reduces the shrink rate.

When choosing our clay bodies, we wanted to make sure that they fired to the same temperature to maximise kiln efficiency. Earthenware bodies will bloat at higher temperatures. Porcelain doesn’t become vitrified until much higher temperatures are reached (meaning it’s still porous at Stoneware temperatures). 

The clay body also determines the shrink rate of the pots. Our Classic Collection has a shrink rate of 12.4%, whereas our Rustic Collection shrinks at 13.4%. This means our Rustic Collection comes up slightly smaller than the Classic Collection. 

 

Caring for Your Pots

Whether you choose a piece from our Classic or Rustic Collection, proper care will ensure your stoneware remains beautiful and functional for years to come.

• Avoid subjecting your pots to extreme temperature changes. Don’t transfer a piece directly from the refrigerator to a hot oven. 

• While our pieces are dishwasher-safe, hand washing will help maintain its appearance over time. Pieces can knock together in the dishwasher and detergents are incredibly abrasive and will dull colours over time.

Remember, each piece of handmade pottery is unique. Slight variations in glaze, size, and shape are part of their charm.