Portable Oven Designs

[david s]

For my mobile oven I cast the dome in one piece which eliminates brick joints and weakness where cracking is likely to occur. I was trying to keep the weight down and made the outershell ferrocement shell 10mm thick. If you want ferrocement stronger you use more mesh rather than more cement. I've also been experimenting with fibre and would chuck some of that in too if I were doing it again. I think the big problem with a mobile oven is the transportation. Road corrugations and speed bumps are not kind to dense,dry brittle material. Oven holding up ok so far.I kept the weight of mine down to 160 Kgs.

[david s]

Wiley,
The fibre to use for reinforcing is fibreglass, but it has to be AR (alkaline resistant) type. The other fibre you refer to is probably the polypropolene fibre, which is quite short and fine and does not provide a lot of strength. It was originally used to fireproof concrete. When the temp hits 165 C the stuff melts and leaves tiny holes that steam pressure can escape through, leaving a fire damaged concrete wall or floor intact. Castable refractories use it in their products for the same purpose. I think we can all benefit from using it too to help when curing our ovens although the outer shell is unlikely to get that hot. Better to use it in the oven walls and the AR fibre in the outer shell. I believe this to be a vital improvement utilizing modern materials.

[Groves]

Wow, how did you keep it to 160kg?

[david s]

The oven interior is 540mm diam and I made the inner dome thinner (50 mm) but compensated by increasing insulation. Also made the outer shell as thin as possible (10mm) and the supporting slab used Hebel (airated reinforced concrete). The flue is a sliding fit, into an outer s. steel sleeve, for transportation.