Dome Fibers

Fibers can optionally be added to the castable refractory material to make a pizza oven dome. Dome fibers serve two different purposes.

Burn-out fibers are fine poly strands that are mixed with the castable material at 1% by volume that “burn out” in the initial pizza oven firings, creating narrow pathways that allow any moisture in the casting material that it turned to steam to escape, without cracking dome material, which can permanently damage its structural integrity.

Stainless steel, basalt and organic material fibers can also be added to the castable material at 1% by volume as a “backup plan” in the event of any larger cracks appearing in the some. These fibers support the structural integrity of the dome and stop large cracks from getting bigger. For example, in the extreme event what a large amount of water is tossed into a fully-fired open, causing thermal shock that cracks the dome.

There is not 100% consensus on which material is best for structural support. While 304 stainless steel is structurally very strong, resilient to high temperates and temperature variability, and will last as along as the oven dome lasts, there are concerns that steel expands more, and more quickly than the cartable refractory, causing tension inside the material, which over time could compromise its strength. That said, Chicago Brick Ovens, a US-based precast oven producer uses stainless steel fibers.

Basalt and organic fibers provide the same structural support as steel fibers, but are based on materials that have thermal expansion rates more closely aligned with that of the castable refractory material.