Clay Questions - Potclays Ltd.

My clay is too hard - how can I soften it?

It should be remembered that some clays are 'thixotropic'. Oxide-heavy clays such as red and black clays are more thixotropic than others. For… Read More About This Question

How can I make my pieces frostproof?

Pottery is damaged when moisture that has been absorbed into the clay, freezes. Water expands as it freezes and the force of this expansion ca… Read More About This Question

How should I safely handle powdered ceramic materials?

Dust from powdered ceramic raw materials, glazes, slips and clay can cause health problems if not properly controlled. The Health and Saf… Read More About This Question

I've fired my vases to vitrification so why is moisture still seeping through them?

In the vitrification process the free silica and feldspathoids in the clay melt and flow into the gaps between the clay particles, welding the… Read More About This Question

Does Potclays clay contain sulphur?

This is a question we are asked quite often. There are trace amounts of sulphur in most ceramic clay bodies. It is at its highest level in bod… Read More About This Question

How can I improve 'toasting' in my fired clay body?

Toasting in the unglazed clay surface can be encouraged by having a thicker cross section of ware, slower drying and higher temperature f… Read More About This Question

What's the maximum firing temperature for your clay bodies?

This is approximately indicated by the vitrification point stated for each clay in our catalogue but, with stoneware, it will be lowered by re… Read More About This Question

What's the recommended firing process for clay and glazes?

We generally recommend biscuit firing at 1000-1060C then following with a glaze firing to a higher temperature which matures both the clay and… Read More About This Question

What is the optimum firing rate to use?

The optimum rate depends upon the thickness of the pots and clay type e.g. thin cast and grogged bodies can be fired quicker than thrown and u… Read More About This Question

What can I do if my clay has frozen?

Clay that has been "lightly-frosted" (that is to say, the freezing has been limited to the surface) is unlikely to suffer adverse ef… Read More About This Question

How much clay do I need for my mural?

We have a handy calculator here on our Technical Information page - direct download link here>… Read More About This Question

Can I use items made from your flecked clays in the microwave?

Yes - the fleck in our clays is created by an iron-bearing compound which is not metallic therefore will not reflect the microwaves.… Read More About This Question

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