Crazing Cracks

(Expansion / Contraction Cracks)

Expansion or Contraction Cracks

Ceramics 101 Some cracking is a natural part of all ceramic materials that come in contact with elevated temperatures, especially with daily heating and cooling. In a Wood Stone oven, the cracking that you may see in the floor or dome of the oven is something that we expect to see eventually in all of our ovens. This is nothing to be concerned about!

Moreover, in our older ovens we allowed for some of the shrinkage/expansion cracks by placing 3 expansion joints directly into the floor casting, and by casting joints into the dome. In the newest of our ovens, we have removed these expansion joints in the floor casting because we found that the oven would make a smaller joint than we could in our casting process.

In fact, it has been our experience that because of the large amount of surface area still in direct contact there is no appreciable difference in cooking performance.

 

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Wood Stone Ceramic Crack Example

Importance of Materials

One thing that you can’t see about the crack is the actual path that it follows and its relative size inside the floor and dome. Because these are coarse grained ceramic materials, this crack does not extend through the ceramic as if it was cut by a saw.

It meanders back and forth through the 4″ thickness and decreases in size from the hot face to the insulated outside surface.

The roughness of this crack actually holds the cracked surfaces rigid, and prevents it from coming apart and shifting. This is the key. All floors and domes crack – ours is designed not to shift afterwards causing cooking problems.

 

 

 

All Ceramics Crack. How is the Unit Physically Supported?Wood Stone Ceramic Crack

The other thing that you can’t see looking at the inside of the oven is how it is supported. There is a metal exoskeleton that connects the floor of the oven to the dome, and that also surrounds the exterior surface of the floor and dome.

This exoskeleton provides support and direction for the ceramics, and further ensures that no shifting can occur. In the image at right the containing force of this support is indicated by the red arrows.

If any crack affects production in any way, just give us a call. We take the service commitment to our customers very seriously. We will do our part to provide you with many years of trouble free production. We hope that this allays any concerns you may have. If you have any questions please call us to discuss them at 800.988.8103.