The Firing Box

Lately I’ve been firing in the 2.5″ tall box rather than the 4.5″ tall. I elevate it on posts (broken tiles will do) so it’s as high as possible in the kiln chamber. The bottom of the box is right above the lowest heating element, so the heat can flow under the box and up.

I use this box in both the front loader and the top loader. The size of the box and the placement in the kiln allow me to fire in two layers in the front loader as well, with full sintering!

I also stopped using the lid, so any stainless steell tray that is no higher than 2.5″ will serve the purpose. My student Suzanne Roady was unable to sinter pieces that kids made in a school project. The pieces were 0.5″ thick. Elevating the box and removing the lid resulted in full sintering.

Firing without a lid, though, will require purchasing carbon more often. A lot of it burns leaving ashes behind.

7 Responses to “The Firing Box”

  • Dinah Bourdon Says:

    I notice that there’s a lot of residue on the walls of the kiln. I find that I have to vacuum my kiln after every BC firing. Does the excess ash and/or binder residue harm the kiln or the thermocouple? Do you need to clean the thermocouple at all, and if you do, how’s that done?

  • Lisa Says:

    I just want to say how much i admire your work and all that you share.
    I’ve been experimenting with Bill’s new copper clay and was so greatful to come across your newest book and then found your site.I cant wait to get some of your copper and bronze powder and order your book! This has to be one of the best writen and understandable books on metal clays i’ve seen. I will be talking about it and refering it to all my students and anyone eles who wants to give this incredible medium a try.
    Thank you so much……Lisa

  • Administrator Says:

    It is indeed recommended to vacumm the kiln after each firing. Eventually the carbon may filter through the muffles and damage the heating elements. I would leave the thermocouple alone, though, except for making sure that it sticks into the kiln chamber.


  • Lin Altman Says:

    Can you leave the lid off for the entire firing?

  • Hadar Jacobson Says:


    I’ve tried that. The carbon burns too fast and by the end of the firing only half the amount is left, leaving the pieces inside exposed to oxygen.

  • Sintering Issues | Hadar’s Blog Says:

    […] 4. If you use a 4″ tall box, place your pieces horizontally, as high as possible in the box. If you place them vertically, the bottom of the pieces may not sinter. For more about the box, see here. […]

  • christine Says:

    Hello! I’ve been reading your blog for a long time now and finally got
    the bravery to go ahead and give you a shout out from Dallas Texas!

    Just wanted to say keep up the good job!

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