How to Make a User-friendly Firing Box

As I promised, here are the instructions for making the firing box.

When handling the fiber blanket it is recommended to wear a protective mask and gloves. An alternative to the fiber blanket will be discussed below.

Cut a square out of the fiber blanket, 2 inches longer than your kiln shelf on every side.


Cut off a 2″ square at each of the four corners of the blanket.


Fold the flaps upward and pinch the sides together.


At first the walls may not stay upright. When placing the box in the kiln, support each side with a post. With every firing the box will become more and more stable, and eventually you won’t need the posts.

Alternatively, as Mary Ellin D’Agostino suggested, you can stitch the sides with high-temp wire.


It is important that the walls of the box are a little away from the walls of the kiln chamber.

This box leaves the kiln perfectly clean. It can be used many times. I haven’t replaced mine yet.

In the past I have tried ceramic boxes. I used bisques and they broke after one firing. However, this ceramic box will not break.

t-Fiber alternative

All it is is a ceramic kiln shelf with posts arranged around it. The carbon stays contained in the box and does not spread in the kiln. You can add more posts to build a deeper box.

6 Responses to “How to Make a User-friendly Firing Box”

  • Carolyn Says:

    Are you saying this is an either/or solution or do you put the fiber blanket ‘box’ inside the one made of kiln shelves?

  • Hadar Jacobson Says:


    You can use this structure instead of a fiber blanket box, or place the box inside it. If you place the box inside it, I would remove some of the the posts, and leave only those that are necessary to hold the walls upright.

  • Alison Says:

    Would this solution work with all types of copper and bronze clay depending on size or is it just for quick fire clay?

  • Hadar Jacobson Says:


    I believe it will improve the results of firing all brands of clay.

  • Trish Hepburn Says:

    Are you saying Hadar’s White Bronze cannot be fired in the stainless steel box that is usually used with the Paragon kiln? What is the fiber blanket made of? If the box is usable over and over, a 50 ft. roll would be a waste to buy. Please clarify. I tried firing the goldie snow bronze and it burned up.

  • Hadar Jacobson Says:

    Trish, Since I wrote this posting I change my firing box to a circular stainless steel bowl, like a pet dish. You can see detail in the instruction manual at:

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