Dear Art
>Where we really take the most heat on every burn is at the top, followed by the grate at the bottom. Using a k-type digital thermometer I am getting readings which average between 500-800c off the ND Estufa Finca and we are working in a humid tropical coastal environment. It is eating our stoves for lunch! Please delete the compilation of messages when you hit reply. The temperatures you have are high enough that only a couple of metals will be useful. Principles: If you use metal, do not put insulation behind it. You must either waste a bit of heat or use it for preheating air. There is no point in insulating metal because it will evaporate before your eyes (and into your lungs). Try to get 3CR12 or 409 for metal parts. It can take 730 deg continuously. It is much cheaper than SS304. Most commercially available SS (304 or 308 or 316) is for restaurant and food-grade handling systems and is not appropriate at all for stoves. It has a low tolerance for heat because the Chrome, when hot, precipitates into clumps of Cr and leaves the oxidation sites free, resulting in rapid deterioration. It is also not very strong or hard, though it spot welds very nicely. Because you are on the mainland you can get clays and you should embark on a long term investigation to produce a clay mix and firing cycle that makes a lot thermal expansion, heat shock resistant ceramic. If you can reach 5 x10-8/°K you will have something that everyone will appreciate and the cracking and low durability will be things of the past. Regards Crispin
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