Glass Kiln Refractory Material
Is An Insulation Medium

Glass kiln refractory materials are generally either fire brick or ceramic fiber products that are used to insulate or act as an accessory during the glass fusing process.


Fire bricks are used as a glass kiln refractory insulation material inside some glass fusing kilns, heat quickly and are capable of withstanding high temperatures.

Some fire brick glass kilns will fire fusing glass, metal clay, enamels as well as high fire ceramic clay.

Heating elements are normally pinned and held in grooves in the brick walls and must be kept clean to prolong life and prevent the elements from burning out.

Any foreign matter left on a heating element can cause it to burn out.

As the elements are exposed, they can be easily replaced.

Fire brick kilns must be kept clean as brick dust can fall if the kiln is moved.

Kilns should be regularly vacuumed.

Small fire bricks can be purchased and used as kiln posts or as glass dams.


There are ranges of ceramic fiber products that are used as a glass kiln refractory material in different aspects of warm glass fusing.

Ceramic fiber is quite often used to insulate a glass kiln. Called a Muffle, it is usually in one piece with the heating elements molded into, and protected by the fiber insulation.

If an element fails then the complete Muffle will need to be replaced.

They are far more expensive to replace than a fire brick kiln element.

Generally, this style of glass kiln will not reach the high temperatures of fire brick kilns.

Fiber Blanket

A flexible long lasting fiber blanket ranging from 1/2' to 2" thick. Quite often used to hold hot glass and slow down the cooling cycle. Used frequently by hand made glass bead makers.

It may be found as an insulator in some glass kilns.

Can be used as a mold for glass slumping, it needs to be coated with aspecial rigidizer so that it will hold its shape.

Fiber Board

A rigid long lasting fiber board 1/2" to 2"thick.

Fiber board may be used as a kiln shelf, mold material or as a glass dam.

Care must be taken when working with fiber blanket or board as some of these materials can be carcinogenic.

It is advisable to wear a mask or respirator when in contact with these materials.

Ceramic Fiber Paper

As discussed in Art Glass Supplies fiber paper is used to insulate between fusing glass and a kiln shelf to prevent the glass fusing to the shelf.

Twisted Fiber Rope

Fiber rope is about 3/8" thick and can be used to create various effects during glass fusing, such as leaving holes and channels open in fused glass.

This rope can be unwound into three 1/4" diameter pieces and then into three 1/8" pieces of rope.

It is ideal for making holes in pendants or glass bails and makes finishing art glass jewelry simpler than having to glue metal bails to the fused glass jewelry piece.

The rope can also be used for kiln carving or for leaving designs in fused glass.

Return From Glass Kiln Refractory To Art Glass Supplies
Return To Home Page