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High temperature refractory insulation made from... bread?  RSS feed

 
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pollinator
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I've been watching this quite entertaining youtube channel with a Canadian fellow doing all sorts of nifty experiments in his shop, and I thought this video might spark some discussion among the RMH crowd.  Essentially he is pyrolyzing regular old wonderbread and turning it into a highly insulative "carbon foam."  He does some heat testing with a thermocouple and an acetylene tourch, and the results are pretty dramatic.  Could this be a way for permies and homesteaders to create our own low cost refractory insulation?  I do imagine it is quite fragile, but the process is so simple, and the raw materials are non-toxic and widely available.
 
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Hi, I will not comment on the refractory use of the so called "DIY carbon foam" .But this is kinda carcinogenic.
A quote from wikipedia "Benzo[a]pyrene is a polycyclic aromatic hydrocarbon and the result of incomplete combustion at temperatures between 300 °C (572 °F) and 600 °C (1,112 °F). The ubiquitous compound can be found in coal tar, tobacco smoke and many foods, especially grilled meats." ....." Its diol epoxide metabolites (more commonly known as BPDE) react and bind to DNA, resulting in mutations and eventually cancer. It is listed as a Group 1 carcinogen by the IARC. In the 18th century a scrotal cancer of chimney sweepers, the chimney sweeps' carcinoma, was already connected to soot."
 
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I have experimented a bit (and rather amateurishly) with this stuff, after seeing someone post this same video.

There is a thread on it in the rocket stoves section of the energy forum, I think

Hoping to make more and do some more extensive experiments, after setting up a better pyrolization setup.

As for the concerns raised above, it is not really any more toxic/carcinogenic than making bio-char... If one's process burns the smoke, then not an issue.

  And you don't freak out when you burn toast in the toaster do you?  You don't breathe nasty smelling toast smoke more than you have to, but you don't treat the room like an EPA superfund site either...

  The pyrolyzed bread it's self is about as carcinogenic as activated charcoal... IE: not carcinogenic
 
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I think it important to mention context.

In the context of a food item, I would agree you don't want to pyrolise bread before you eat it.

But one doesn't eat refractory insulation, does one?

I would be very comfortable using perfectly pyrolised bread as refractory insulation in an RMH, as I am not intending to eat the refractory insulation, nor am I intending to take large hauls off of the chimney.

Finally, a use for wonderbread!

-CK
 
Matthew Goheen
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Chris Kott wrote:I think it important to mention context.

In the context of a food item, I would agree you don't want to pyrolise bread before you eat it.

But one doesn't eat refractory insulation, does one?

I would be very comfortable using perfectly pyrolised bread as refractory insulation in an RMH, as I am not intending to eat the refractory insulation, nor am I intending to take large hauls off of the chimney.

Finally, a use for wonderbread!

-CK



  I think the post I was responding to was about about carcinogenic compounds that would be in the smoke released during the pyrolizing of the bread... which I think is a non hazard if one avoids breathing the smoke produced during the process. 

  I wasn’t suggesting eating it was a good idea, but was responding to the other poster that I didn’t think the production process would be hazardous if conducted safely outdoors,  and was saying the compounds are not particularly hazardous at low concentrations.

  And then I was pointing out that the pyrolyzed bread would not have these compounds but would be pretty much pure carbon.

  Don’t disagree at all that it’s an interesting high heat insulation, but in further playing with it, I found that what I was producing would burn like charcoal if exposed to oxygen.   So either my process did not get it hot enough, or this insulation would have to be protected from airflow entirely.

  It is possible I didn’t get my samples “carbonized enough though.  I would like to try using them as a grog/filler in a cast refractory mix
 
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It seems to me that the burnt toast is carbon... biochar... charcoal. If I'm correct and not missing something then any carbon substance could be an ingredient in an insulative mix as long as oxygen is not present in high enough amounts to trigger combustion at certain temperatures. That's basically what people were doing when they experimented with using sawdust in an insulation mix: the sawdust pyrolized and apparently stayed stable in a honeycomb kind of configuration but was also fragile which wouldn't matter if it were in between the firebox and the outer masonry skin of a heater.
 
Matthew Goheen
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michael Egan wrote:It seems to me that the burnt toast is carbon... biochar... charcoal. If I'm correct and not missing something then any carbon substance could be an ingredient in an insulative mix as long as oxygen is not present in high enough amounts to trigger combustion at certain temperatures. That's basically what people were doing when they experimented with using sawdust in an insulation mix: the sawdust pyrolized and apparently stayed stable in a honeycomb kind of configuration but was also fragile which wouldn't matter if it were in between the firebox and the outer masonry skin of a heater.



  Thank you, that is good info about it working well within a protective structure... I may have to try it as a grog in one of my geopolymer refractory experiments.
 
michael Egan
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and thank you for experimenting and sharing ideas/results. We all benefit. Keep going!
 
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Amazing what people come up with !

I like to use and promote the compact mineralwool as noncombustible insulation that is reasonable in  price. ( about $50 for 48 sq ft)

It even looks abit like mouldy(green) bread.

Here's a pic of it , the evil monster Home Depot carries it or can order it in.

Its flexible yet rigid and comes in handy 2x4 ft sheets.

I have used it to protect wood when building a fireplace close to wall.

It is also in general very good for insulating and stuccoing /parging any surface inside and out and should be used alot more. It breathes , so good for upgrading older buildings without vapor barrier.

Adding some other shots just to show a common use for this system.
SANY1720.JPG
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package roxul 2x4ft sheets.
SANY1721.JPG
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loose 1.5 inch 2x4 ft sheets R7
SANY1723.JPG
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insulating basement wall
SANY1729.JPG
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parged with mortar and brushed .
 
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