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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Dear Art<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='color:#1F497D'>></span>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!<span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Please delete the compilation of messages when you hit reply.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The temperatures you have are high enough that only a couple of metals will be useful.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Principles:<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>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). <o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Try to get 3CR12 or 409 for metal parts. It can take 730 deg continuously. It is much cheaper than SS304. <o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>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.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>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<sup>-8</sup>/°K you will have something that everyone will appreciate and the cracking and low durability will be things of the past.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></div></div></body></html>