4" ceramic fiber board enough?

[Nicoka]

Second build, first mobile build for 40" dome oven. Still not sure what I'm doing. I built a sturdy wood frame topped with 3/4" plywood and 1/2" cement board. Planning to put a circle of 4" ceramic fiber board down with my brick cooking surface on top. That's 6.5" between the fire and wood frame. Is that enough? Any thoughts on this plan? Trying to keep the weight down. Any help would be appreciated

[david s]

When you say mobile, do you mean on a trailer or a movable stand? Timber stands are not recommended as they deteriorate if left in the weather, welded galvanised steel is far better. Plywood is a poor choice under any ove. Nigh on impossible to replace, a harbour for moisture and not particularly heat tolerant. A 40” oven will be extremely heavy.

[Nicoka]

It's in an old horse trailer I modified to hold it, so will be protected from the elements. The opening for the oven will be from a door above the wheels on the side. Definitely going to be heavy and may drop down to 38in. Perhaps double up on cement board? Not planning to drive it far either.

[david s]

Ah, ok
two things then, both related. Add shocks to the horse trailer if not already and don’t build it in brick or the oven will rattle to bits. Some cast manufacturers offer one piece cast domes rather than multi sectioned ones specifically for mobile ovens to overcome this problem.