Home

Topics: Art Clay®, Warping, Firing

Q.
I notice that after firing my Art Clay with a torch, it no longer lies flat (when it was flat before firing). Am I firing too long, or not long enough?
- Heather
A.
Warping or distortion often happens if the flame of a torch is concentrated for too long in one part of the piece or when a piece is too large to be fired with a torch. A piece that is heavier than 25 grams or is larger than a half-dollar, in thickness and diameter, should be fired in a kiln.

If your piece is smaller than a silver dollar and less than 25 grams, go through this check list before firing your next piece:
  • The object being fired must be completely dry
    • If you are unsure if the piece is dry, place it onto a mirrored surface; let it stand for a moment then remove. If there is a haze at all on the mirror, the piece is not dry. Wait overnight before proceeding.
  • Place the dried piece onto a fire block
    • Do not use ceramic since it can crack or splinter when used for heating metal clay due to the concentrated heat in one area
  • Trace an outline of the piece onto the fire block
    • The outline will help you gauge how much the piece shrinks when fired. If the finished size is not 8% (or more) smaller than the original size, it was not properly sintered (fired). Start over.
  • Dim the lights in the room, if possible
    • The dim environment will enable you to assess the color of the glow as the piece is heated
  • Set a timer for the appropriate amount of time:

    Clay Volume 5g 6g - 15g 16g - 25g
    Firing Time 1 - 1.5 min 1.5 - 2 min 2 - 2.5 min

  • Put on your safety glasses
  • Start heating the piece with the torch. Be sure to keep the torch moving in a circular motion so as not to heat one part of the piece longer than the rest. Once it reaches a peachy salmon color, start the timer. Heat until the time is up.
Materials Resources Additional Materials Additional Resources

Recommended Just for You


Sign Up for Email Specials and Beading News
Sign Up
for Email Specials and Beading News