A shrink rule is a handy tool that will let you know how much your clay shrinks.

Tools & Materials
Your Favorite Clay
Flexible Rib (Large Yellow Mud Tools)
Ruler
Rubber Tipped Tool
Clay Knife or X-Acto (Dolan 220S)
Ware Board

Here is the formula to figure out the shrinkage rate of your clay.

1.Make your shrink rule as shown in the class
2.Once it is fired to your glaze temp measure the length of the line you made.
3.Use the below formula to solve for S.

S=(1-F/M)x100

M=length of line in original moist clay slab with regular ruler (This number is 10")
S=percentage of shrinkage
F= length of line in finished clay slab