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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><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 Julien<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><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>I agree you are seeing that: <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'><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>>…</span></b>When I added a 15 cm riser on top of the burner, the center of the flame became somewhat depressed. That could mean that there could be a rather interesting circulation pattern going on with some secondary air going down in the center, then circulating up with woodgas at the outside in a <span style='background:yellow;mso-highlight:yellow'>toroidal</span> vortex ... or maybe it is just a 'pigment' of my imagination.<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'>It is a toroidal flow probably up on the outside, down in the centre. You should be able to follow small sparks with your gaze because you have a char burn going on at the surface. <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 it is circulating ‘too much’ it will increase the flame height. You can break it up with a few jets pointing in the opposite direction.<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 pops you heard drying the refractory is exactly the problem. I suggest the following regimen:<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'>105 for 1 least an hour (use the warming drawer, not the oven) and possible much longer. Then increase it now and then, 15 minutes or 30 minutes, by 25 degrees. The plan is 135 degrees per hour or less, to the highest temperature you can get which is probably 275 C in a baking oven. This removes ‘crystal water’ meaning H2O bound in the chemistry of the materials. It is not ‘moisture’ in the regular sense but it still makes steam when it comes out. <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 popping is spalling from steam pockets exploding out. The temperature change rate was too high. It doesn’t stop until 600 C but that is hard to do without a clay firing oven. If you can get to 600, hold for 1-3 hrs to get the carbon out of the interior, then you can ramp up to the final firing temperature at 150-200 degrees per hour. That might be 1100-1280. Modern kilns have ramping software in the controller.<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'>When running the stove you can certainly get a nozzle temp of 900 (glowing) so try to do it gently on the first run.<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>