Strength of steel Steel loses 90 percent of it's strength at around 800 degrees c. or 1450 degrees f. This is the figure for mild structural steel, of the sort that home depot angle iron would be made of. It will also rust in a hot and corrosive environment. Stainless would be resistant to corrosion, but may not be any stronger in high heat environment.
That said, a lot of pompeii ovens have been built this way, and we haven't heard of any failures yet. If you are concerned, you could use a refractory casting, or build a fire brick arch instead. James has also said he will sell the flue part of the manufactured oven separately. |