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Post by biothermoguy on Feb 23, 2014 9:35:57 GMT -8
Hi guys, I have followed your forum and what a load of incredible info. I am an old guy that just learned how to use the computer so bear with me. I need to ask you guys in all of studies what is the best material to coat my cardboard tube heat riser. Donkey you seem to be the man, I you had one mix what would it be? I don't want to skimp too much on cost, don't want to replace soon. Anyway, could you give me a blow by blow how to coat and times drying between coats. How the sintering process works. I am just fascinated with the work you guys have achieved and the level of research you have dedicated thanks a million.
regards, Paul
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Post by Donkey on Feb 23, 2014 22:38:17 GMT -8
I'm inclined to recommend Matthew walker's perlite/clay/waterglass (sodium silicate) mix. I think that if you copy/paste the following (or alter it around till you get what you are looking for) into a google (or other search) bar, you will find it: site:donkey32.proboards.com matthew walker heat riser mix perlite stove cement
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Post by biothermoguy on Feb 25, 2014 21:31:56 GMT -8
Thanks Donkey for the information. Could you give me a background and usage on water glass? How long you been studying combustion systems? Take care
Paul
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Post by Donkey on Feb 26, 2014 22:07:53 GMT -8
Water glass also called sodium silicate (sodium metasilicate), one of it's uses is in refractory materials as a binder (our use). I learned about it from my friend, Kiko Denzer who is known for his earthen oven book among others. www.handprintpress.com/I've been at Rocket Stovery (and other fire gizmos)for around a decade, but I've ALWAYS been a bit of a pyromaniac..
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Post by biothermoguy on Feb 27, 2014 22:35:21 GMT -8
Thanks. So is the fiber material (straw etc)l still needed in the mix if I use the Perlite, clay and the water glass mix? Do you have any thoughts on the use of Lava rock for a thermomass? I know it is more of insulator, but I would like to make a portable unit not so darn heavy with brick cob etc. I seem to have read somewhere that it has some filtering properties as well. I would like to know any info you have on the basic red home depot lava rock utilized in the BBQ. I think I have a bit a pyro blood myself.... always tinkering for a better system....... Have a great one.
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Post by Donkey on Feb 28, 2014 8:43:45 GMT -8
You don't need fiber inside the heat riser. I can't really speak to the usefulness of pumice. I have used it to insulate under the firebox, but i can't get down there to tell you how well it works.. As a general rule, heavier stuff is better thermal mass and reverse that for insulation. Can't have thermal mass without it being bloody heavy! If you want it portable, you either want to forget the mass or make it removable.
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Post by satamax on Feb 28, 2014 11:08:52 GMT -8
For heat storage, fist to head sized pebbles above a half barrel bell. There's a posibility of air movement from convection charging the stones. And you can even force air through, to control your heat release.
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Post by biothermoguy on Mar 2, 2014 18:52:38 GMT -8
I have read a bit on the pumice and it has some interesting properties. I see some use it on the outer shell for insulation around the riser. One thing I like about that idea is the easy removable to check on the components of the stove. Anyway what I have decided to make the riser with is the stove cement first coating on the tube and build it up to about a quarter inch. Does this sound good to do for the hot face? Then next the perlite, fire clay mix over the stove cement filling in around up to the next enclosure tube. The carpet tube is 5" and I thought the outer tube will be 8' and I will fill 3" with the materials. Then I think I will try the Lava rock and see how it reacts. If that doesn't work what do you guys do on the outer layer? Just checking on the best mix for the outer shell. I have a load of other question don't want to overload you. Really am learning a bunch hookin up with this site! Trying to find the answers in previous posts so you don't have to do it again. Thank you Donkey and Satamax and all of you for all the effort.......
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Post by manuel on Nov 20, 2014 9:08:09 GMT -8
I'm inclined to recommend Matthew walker's perlite/clay/waterglass (sodium silicate) mix. I think that if you copy/paste the following (or alter it around till you get what you are looking for) into a google (or other search) bar, you will find it: site:donkey32.proboards.com matthew walker heat riser mix perlite stove cement Hello! I've tried to find the recipe using the search tool (even google) but I've been not able to. Could some one please point me to it? I'd like to try it for a heat riser and it would be good to have some proportions to beguin with. Thanks a lot
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Post by matthewwalker on Nov 20, 2014 9:13:44 GMT -8
Manuel, it's 14:14:1, fireclay/perlite/furnace cement. You can add glass fibers for a little more tensile strength, but it's not necessary. Here's the videos that show the mix...
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Post by photoman290 on Nov 20, 2014 16:09:23 GMT -8
don't forget sodium silicate is very caustic. treat like caustic soda, gloves, eye protection. don't breathe the dust if you can help it.
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