1. What is Pottery Shrinkage?

Pottery shrinkage refers to the reduction in size that occurs when clay dries (dry shrinkage) and when it's fired (firing shrinkage). This calculator measures the total shrinkage percentage from greenware to fired pottery.

2. How Does the Calculator Work?

The calculator uses the pottery shrinkage formula:

Where:

• Green Size — Original measurement of the clay piece before drying and firing (inches)
• Fired Size — Final measurement of the piece after complete firing (inches)

Explanation: The formula calculates the percentage reduction in size from the original greenware to the final fired piece.

3. Importance of Shrinkage Calculation

Details: Understanding shrinkage rates is crucial for potters to create pieces that will end up at the desired size after firing. It helps in planning dimensions and creating molds or templates.

4. Using the Calculator

Tips: Measure your greenware carefully before drying. After firing, measure the same dimension. Enter both values in inches. Green size must be larger than fired size.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical shrinkage rate for pottery?
A: Most clays shrink 5-15% total (combining drying and firing shrinkage), but this varies by clay body and firing temperature.

Q2: Why measure in greenware stage?
A: Greenware measurements provide the baseline before any shrinkage occurs. Bone dry measurements would only show firing shrinkage.

Q3: Does shrinkage vary by direction?
A: Yes, clay often shrinks more in the direction it was thrown or rolled due to particle alignment.

Q4: How can I account for shrinkage when making pottery?
A: Multiply your desired final size by (1 + expected shrinkage percentage) when creating your piece.

Q5: What affects shrinkage rates?
A: Clay composition, firing temperature, particle size, and grog content all influence shrinkage rates.