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Post by coastalrocketeer on Mar 31, 2017 18:35:35 GMT -8
My local pottery supplier sells amorphous silica which is presumably ground finer and is $40 for a 50 lb bag and has none of the additives of the kitty litter, but I'm told can be used the same way.
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Post by coastalrocketeer on Mar 31, 2017 11:13:15 GMT -8
If I am remembering right from Karl's geopolymer forum, I believe that would be sodium metasilicate...
Sold as Red Devil TSP 90 cleaner in the paint prep section at my local ace hardware...
This permies forum post discusses it...
Has to be dissolved in a KOH or NaOH solution, and the reaction is exothermic... So add slowly.
People also apparently use amorphous silica and silica crystal kitty littler as feed stocks.
Lots of videos on YouTube of the mixing process, which should be similar for all.
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Post by coastalrocketeer on Mar 31, 2017 10:48:12 GMT -8
I'm not sure what part of the country you are in, but here in Oregon, the best prices I've seen for castable and other refractories is "hi-temp Inc" out of portland. They have an eBay store, and as is usual for these things, shipping is the killer if you can't pick it up will-call.
They have Kast-O-lite 30 which is an insulating castable... Good to 3000F
The castables they sell are oriented toward kiln making and they have both light insulative and heavy more structural types.
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Post by coastalrocketeer on Mar 31, 2017 10:42:58 GMT -8
I believe that will be a non-insulating & fairly high mass refractory material, equivalent to the heavy fire brick when cured
but I have not used it... So can't be sure.
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Post by coastalrocketeer on Mar 14, 2017 9:31:00 GMT -8
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Post by coastalrocketeer on Mar 13, 2017 23:03:55 GMT -8
I think that air flow in a properly designed batch box would prohibit burning unbonded sawdust as much of it might be sucked into the riser...
If these pressed wood/sawdust briquettes are anything like pellet stove pellets made from compressed sawdust (usually 1/4" diameter x3/8" to 1" long cylindrical pellets) sold around here, they expand into sawdust as they burn and send a lot of ash/partially burned sawdust into the pellet stove interior passages and exhaust ducting...
Might be different in an already heated up rocket stove though... With enough heat in the areas they are blown into to combust them more completely.
I would expect more, heavier ash in the system with regular use of a sawdust based, or straight sawdust fuel.
I could however be totally off base... Just my intuition based on past experience with pellet stoves here in the US.
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Post by coastalrocketeer on Mar 13, 2017 22:46:12 GMT -8
The manifold "main rule" is "avoid making it too small, and thus impeding gas flow."
Peter VanDenBerg has posted a formula somewhere that allows, based on the area and circumference of the opening, to adjust minimum to a proper CSA based sizing for "narrow" manifold shapes like slots and stuff...
I'll see if I can find it for you.
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Post by coastalrocketeer on Mar 13, 2017 18:49:47 GMT -8
Thank you! The drawing filled in some weak spots in my mental image of what you have going on there...
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Post by coastalrocketeer on Mar 5, 2017 15:42:31 GMT -8
That is your first pic, as a direct link... Guess from google it won't just show the picture, at least the way it was linked viewing in Safari on an iPhone.
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Post by coastalrocketeer on Mar 5, 2017 15:40:52 GMT -8
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Post by coastalrocketeer on Feb 26, 2017 2:41:45 GMT -8
I tried making the link with www at the beginning instead of m.youtube... Does it work now?
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Post by coastalrocketeer on Feb 25, 2017 15:22:45 GMT -8
Was looking at threads on geopolymers (Big thank you's to Karl and ALL sharing their research here) I came accross this video and had to drop it here, with the description and see if anyone has experimented with using natural fibers in geopolymers here... Uploaded on Jan 17, 2012Fiber board made with geopolymer withstands direct flame of 3532 F opposite side of 1/2" thick board remains ambient temperature Filler is waste wool www.youtube.com/watch?v=YKMiHnVyC0UI would also like to experiment with natural fibers like wool and also feathers, and perhaps carbon bread foam as well, as admixture/aggregate ingredients... Seems like this stuff he made, (or a similar optimized castable) might be a relatively inexpensive equivalent (or better) replacement for ceramic fiber blanket (and expensive IFB type bricks and boards) in Rocket heater and stove devices...
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Post by coastalrocketeer on Feb 24, 2017 14:47:22 GMT -8
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Post by coastalrocketeer on Dec 23, 2015 0:35:11 GMT -8
Thanks for the information all. I was poking around the McMaster-Carr web site, and found that they carry this product at $86 for a 50 lb bag: www.mcmaster.com/#9876k1/=v2k2h1From the MSDS, this seems to be the product in question: firearmor55inc.homestead.com/I was thinking about starting from equal parts Vermiculite and fire clay, and adding some of this stuff (say half a bag for the core, half for the riser) to help it stick together. Any thoughts? Thanks - Clark Wow! - other than the fact that it's over $100 a cubic foot, that stuff looks amazing! I really want a sample to play with! My thought would be to use a roll of ceramic wool with 1" over my desired inside radius and put a nice 1" layer of that inside, and thinner over the top and outside to provide a stiff, 5000+ degree rated liner/form holding coat for the ceramic wool. Or could be cast into a 1/2" thick inner (and outer?) riser walls and filled with perlite in place. Stable to 5000+ degrees and apparently one test used a 2000 degree flame on a 3-1/2" thick piece and opposite side was only 243 degrees after 12(!!!) hours! Does anyone else think this stuff has serious potential?
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Post by coastalrocketeer on Jan 21, 2014 15:29:19 GMT -8
Talltuk - the heat exchangers, if placed inside of a bell as described, with their gas passages oriented vertically, should create convective flow downward through themselves, in the gasses in the bell, as it cools them...
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