Clay & Shrinkage

Clay Body Blend Calculator

Blend two clay bodies by percentage and predict the shrinkage and absorption of the resulting mix.

Updated

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Body A

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Body B (auto: 100% − Body A)

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Results

calculate

Enter your measurements above and click Calculate.

Why Blend Clay Bodies?

Ceramic artists blend two or more clay bodies to fine-tune working properties, fired color, shrinkage rate, or texture. A common example is blending a throwing body with a groggy sculpture clay to reduce cracking in thick hand-built forms, or combining porcelain with stoneware to achieve translucency with better workability.

Linear Interpolation Method

This calculator uses linear interpolation to estimate the blended body's shrinkage and water absorption. If Body A is 12% shrinkage and Body B is 8%, a 50/50 blend is estimated at 10%. This approximation holds well when the two bodies have similar chemistry. Large differences (more than 4%) introduce non-linear behavior — always test a small sample first.

Compatibility Considerations

Shrinkage Difference

Bodies with more than 4% difference in total shrinkage may create internal stresses in the blend. Fire test bars to confirm.

Firing Temperature

Both bodies must be compatible at the same peak temperature. Blending a cone 06 earthenware with cone 10 stoneware will not work.

Frequently Asked Questions

Why blend two clay bodies? expand_more
Blending combines the best properties of each body — you might mix a highly plastic clay with a lower-shrinkage, more textured body to get a workable clay that fires well at your target temperature with manageable shrinkage.
Is the blend shrinkage truly linear? expand_more
For most practical purposes, yes — shrinkage interpolates linearly with blend ratio. However, very different bodies (e.g., high-silica earthenware + high-alumina stoneware) can behave non-linearly. Always test-fire a small batch.