Shrink Ruler – DiamondCore Tools
Shrink Ruler
Shrink Ruler

Shrink Ruler

Regular price $16.00 Sale

An innovative way to measure the shrinkage of your clay. Works great when making replacement lids for a casserole dish that has been bisque fired. This flexible two-sided ruler has 4 clay shrinkage percentages to aid in matching lids to bowls etc. 14% 12%, 10%, 6%.

Directions: HOW TO USE YOUR SHRINK RULER

To replace a lid for a casserole dish that has been bisque fired, measure the casserole dish with a regular ruler.  Using that same measurement, measure your wet clay with the Shrink Ruler on the side with the closest shrinkage rate to your wet clay.

To replace a lid for a casserole dish that has been glaze fired, measure the casserole dish with a regular ruler.  Using that same measurement measure your wet clay with the Shrink Ruler on the side with the closest shrinkage rate to yours.

Example: If you want a piece to measure 8” after 12% shrinkage, use the 12% scale on the Shrink Ruler to measure 8” on the wet clay.

HOW TO MEASURE THE SHRINKAGE RATE OF YOUR CLAY

  1. Make a rectangular clay slab as thick as you plan to make your piece and 4” X 12”, then with a regular ruler measure and carve a 10” line in the wet clay.
  2. Bisque fire the clay slab.
  3. Measure the length of the same line again with the regular ruler.
  4. Use the following formula to solve for S:     S=(1-F/M)x100                                         M=length of line in original moist clay slab (with regular ruler)                                      S=percentage of shrinkage,                                                                                          F= length of line in finished clay slab (with regular ruler).
  5. Fire the clay slab to maturity and repeat steps 3 and 4 (this will allow you to determine the shrinkage of your clay after both bisque and glaze fired).   Made in USA.