<html><body><div style="font-family: times new roman, new york, times, serif; font-size: 12pt; color: #000000"><DIV>Hello Trevor,<BR></DIV>
<DIV>Instead of importing cement, how about importing clay? I'm sure there will be many who can help you make durable clay stoves. My eco-kalan clay stove fired at 900 degrees Celsius has a proven 6+ years life so far and I expect more years if the stove is insulated completely with ash. You may not have to go back to 3 stones.</DIV>
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<DIV>Rebecca</DIV>
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<DIV style="FONT-SIZE: 12pt; TEXT-DECORATION: none; FONT-FAMILY: Helvetica,Arial,sans-serif; FONT-WEIGHT: normal; COLOR: #000; FONT-STYLE: normal" data-mce-style="color: #000; font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><B>From: </B>"Michael N Trevor" <mtrevor@ntamar.net><BR><B>To: </B>"Discussion of biomass cooking stoves" <stoves@lists.bioenergylists.org><BR><B>Sent: </B>Tuesday, May 13, 2014 10:52:39 PM<BR><B>Subject: </B>Re: [Stoves] question about longevity Re: concrete rocket stoves<BR>
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<DIV>Thanks you for the response. Decades would be wonderful but in todays world is very unrealistic, and in the environment here impossible. Here at 5/6 feet above sea level 80 degrees F plus 100 percent humidity and constant salt even stainless steel does no last. Broken coral aggregate and foraminiferous sand simply do not make a concrete that can tolerate fire. WWII armored tanks do not even exist as rust spots on the reef. On a coral atoll there is nothing to use except calcium carbonate and humus. Everything else is imported at a cost many can not pay.</DIV>
<DIV>In reality here 2/3/4 years is a miracle unless built to standards no one can afford. A solar reflector would be corroded beyond use in 12 to 24 months.</DIV>
<DIV>They were tried and trashed, after the steel legs rusted and collapsed leaving the reflector propped up on pieces of wood. The condensed moisture in say gas or kerosene from simple daily expansion and contraction rusts out tanks in couple years.</DIV>
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<DIV>Without a cost effective viable alternative people will go back to the 3 stone fire. It worked for grandma, it worked in the 19th century and it worked a thousand years ago. </DIV>
<DIV>Michael N Trevor</DIV>
<DIV>Majuro</DIV>
<DIV>Marshal Islands</DIV>
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<DIV style="font-color: black" data-mce-style="font-color: black;"><B>From:</B> <A title=doseifert@googlemail.com href="mailto:doseifert@googlemail.com" target=_blank data-mce-href="mailto:doseifert@googlemail.com">Dr.-Ing. Dieter Seifert</A></DIV>
<DIV><B>Sent:</B> Tuesday, May 13, 2014 2:41 AM</DIV>
<DIV><B>To:</B> <A title=stoves@lists.bioenergylists.org href="mailto:stoves@lists.bioenergylists.org" target=_blank data-mce-href="mailto:stoves@lists.bioenergylists.org">Discussion of biomass cooking stoves</A></DIV>
<DIV><B>Subject:</B> [Stoves] question about longevity Re: concrete rocket stoves</DIV></DIV></DIV>
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<P class=MsoNormal><SPAN lang=EN-US style="mso-ansi-language: en-us" data-mce-style="mso-ansi-language: en-us;">Dear Michael N Trevor,</SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US style="mso-ansi-language: en-us" data-mce-style="mso-ansi-language: en-us;"></SPAN> </P>
<P class=MsoNormal><SPAN lang=EN-US style="mso-ansi-language: en-us" data-mce-style="mso-ansi-language: en-us;">Are we not supposed to strive for a durability of our cookers in the range of decades to avoid that there is a continuous production of waste? So I want e.g. to pass my parabolic solar cooker to my grandchildren as it is not degraded during many years of intensive usage.<SPAN style="mso-spacerun: yes" data-mce-style="mso-spacerun: yes;"> </SPAN>And one day, after decades, they may repair it or recycle it.</SPAN></P>
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<P class=MsoNormal><SPAN lang=EN-US style="mso-ansi-language: en-us" data-mce-style="mso-ansi-language: en-us;">With kind regards</SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US style="mso-ansi-language: en-us" data-mce-style="mso-ansi-language: en-us;">Dieter</SPAN></P><BR>
<DIV><BR></DIV><BR>Am 14.05.2014 04:37, schrieb Michael N Trevor:<BR></DIV>
<BLOCKQUOTE cite=mid:08C4D07756FB4F189DF76D4CFD51CB11@cmipc>Re-asked-- <BR>
<DIV><BR></DIV><BR>There are wide variety of rocket stove designs shown on various YouTube movies. <BR>Primarily variations on stacked hollow blocks or 6 gallon buckets with a removable PCV elbow. <BR>both types have the distinct advantage of being simple inexpensive and quick to make. <BR>
<DIV><BR></DIV>However does anyone have any actual longevity information? <BR>For instance Quickrete in the 60 pound bag is a nice mix of cement, hard sand and nice small pebbles which with should make a nice <BR>dense concrete. As configured the sample stove has about a base 2 inches thick, and 4 inch walls. Could this be expected to last a few weeks, <BR>a few months or even a year or more. The bag of cement here cost a little over 7.00 with tax. With propane costing a 1.00 plus even 2.00 <BR>Return on investment is a week, however making a new stove weekly just does not cut it. Some might it consider if the stove lasted 6 months. <BR>If it can be a year or so it could be feasible especially if it they were already made and available. <BR>This issue of longevity could be important. I will be able to answer this myself in the future as I all ready made two. But if some one can answer in advance it would be appreciated. <BR>
<DIV><BR></DIV><BR>Michael N Trevor <BR>Majuro <BR>Marshall Islands <BR>
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