Firebox construction-- Boiler plate or Stainless for Outdoor Furnace?

A. No, but it is major league cheaper.

A. Hello:

Without knowing just exactly what your intentions are it will be a little difficult to tell you which is "Better" when debating the qualities of Stainless vs. Boiler Plate. Do you plan to build your own system or buy a pre-fab unit? If you plan to buy a system keep the following in mind. Stainless Steel in a lot of pre-fab units is a very cheap grade and might not give you the service life you would expect. The SS in these units is not a very heavy grade and could have a tendency to warp after a length of time. "Boiler Plate", as you refer to, is a better grade of material than "Mild Steel" and would be more than suitable for your application. I built my own system using mild steel (1/4") and lined the whole firebox with fire brick and have had absolutely no problems with it. SS is quite difficult for the DIY'er to cut and fab parts from and it is VERY expensive to buy. SS will warp dramatically when exposed to heat sources. Mild steel is not cheap, but is nowhere near the cost of Stainless. A small cutting outfit and a stick welder and you are in business. What type of fuels do you plan to use? Coal burns much hotter than wood so if you plan to use the former then you would need to take that into consideration. SS is OK but you can use corrosion inhibitors in your heated medium to prevent mild steel from rusting. All things considered, my preference would be mild steel for a lot of reasons.

Hope this helps.