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Post by pinhead on Nov 21, 2014 12:17:48 GMT -8
I've been wanting to build a heat riser for a batch box using this stuff but haven't been able to find a cheap enough way to make it. Has anyone ever looked into this stuff? www.aerogel.org/
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Post by matthewwalker on Nov 21, 2014 12:23:19 GMT -8
I did. It's just so dang cool! Sound proof too. Anyway, at this point I think it's a bit exotic. Hard to find, hard to make, and expensive. I think it would be super fun to experiment with.
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Post by pinhead on Nov 21, 2014 12:39:18 GMT -8
Yeah, that's about as far as I got, too. I've been hoping someone had found an easier/cheaper way to make the stuff and published it online, though that will probably take quite a while.
I suspect you would need some type of radiant barrier, considering the stuff is semi-transparent.
And I suppose the chemical efficiency of the recently-developed P-Channel, S-Portal, and your Walker Port wouldn't be much improved with better insulation since there's not a whole lot left to burn.
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Aerogel?
Nov 21, 2014 12:41:29 GMT -8
via mobile
Post by PNW Dave on Nov 21, 2014 12:41:29 GMT -8
I've thought about aerogel too, but looking into it I only see max temps of about 350F or pyrogel blankets with max temp 1200F. Not really high enough temp for our uses.
Is there another type of aerogel with higher max temp that I haven't come across?
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Post by pinhead on Nov 21, 2014 12:54:45 GMT -8
I've thought about aerogel too, but looking into it I only see max temps of about 350F or pyrogel blankets with max temp 1200F. Not really high enough temp for our uses. Is there another type of aerogel with higher max temp that I haven't come across? Alumina Aerogel
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Aerogel?
Nov 21, 2014 13:04:28 GMT -8
via mobile
Post by PNW Dave on Nov 21, 2014 13:04:28 GMT -8
Ah ha! That's more like it.
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Post by Deleted on Nov 22, 2014 5:23:04 GMT -8
An aerogel is an open-celled, mesoporous, solid foam that is composed of a network of interconnected nanostructures and that exhibits a porosity (non-solid volume) of no less than 50%.
50% can be easily achieved by geopolymers. Significantly higher porosity would be possible. Drying of highly porous gels may be demanding. High porosity may require drying in humidity saturated air. Very high porosity requires freeze drying to prevent destruction during drying by capillary force. During cold winters freeze drying does not require much expensive equipment. Alkali Activated Aerogels ritdml.rit.edu/bitstream/handle/1850/10097/FSvingalaThesis06-18-2009.pdf?sequence=1
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Post by Donkey on Nov 23, 2014 0:39:38 GMT -8
Wow.. Geopolymer aerogels. Who'da thunk?
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Post by PNW Dave on Nov 23, 2014 3:46:53 GMT -8
Wow.. Geopolymer aerogels. Who'da thunk? Karl
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Post by photoman290 on Nov 24, 2014 13:28:39 GMT -8
this is not too far from experiments done this summer by smarty using aluminium powder and geoploymer mixtures. still needs some work but it is in the geopolymer thread. i intend to do some experimenting at some point. no workshop at the moment so will have to wait till i can work outside without getting rained on,a tall order in the UK in the winter.
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Post by Deleted on Nov 25, 2014 5:19:27 GMT -8
Aerogels cannot be produced by foaming agents like aluminium powder and lye. Mesoporous means pore sizes smaller than 50nm, 0.00005mm, less than one thousandth the thickness of a hair.
Actually it is much simpler than using foaming agents.
Assumed the solids in a geopolymer mixture habe an average specific gravity of 2.5 and the resulting solids will have not less than 2.5.
2.5 parts solids and one part water per weight will result in a 1:1 volume ratio. Once the water is removed (without shrinkage) there will be an air/solid ratio of 1:1.
Eg. Metakaolin requires significantly more water than 1/2.5 for a castable mixture.
Without too much waterglass quite a lot geopolymers made of very fine materials will fulfill the minimum requirements for an aerogel with ease.
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