Fireproof Carbon Foam From Pyrolysed Bread

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Carbon foam has some very useful properties: It is an excellent thermal insulator.

The fact that it's made from bread adds "much wow!" to a very simple process.

You could conceivably cover you space rocket in these ablative tiles for re-entry. Because Science! NASA! Outer-space! Clickbait!

Step 1: Weld a Steel Box With a Hole in It

You'll need a container that you can heat the ever living tar out of. Literally, we are going to roast the tar out of bread.

The hole is so hot gas can escape and the box doesn't blow up and kill you.

I made my hole threaded so I could add a bolt and let only a tiny amount of gas out through the threads.

I also purged the box with Argon gas. A redundant step; but, belt and suspenders amirite?

I'd leave a chemistry joke here, but all the good ones argon.

Step 2: Roast the Box With a Propane Torch, or Campfire, Until No More Yellow Flames Are Visible

The yellow flames are hot volatile gasses leaving the box. Once the yellow flames die down, you know your bread has been turned to carbon foam.

Step 3: Much Fun! Experiments! So Enjoyment! Very Hyperbole!

I blast the carbon foam with an oxy/acetylene torch and melt aluminum directly on the tile.

Then I checked with a thermocouple how well the tile was insulating from the torch blast.

I also checked the electrical resistance. It is very high! From my previous tinkering with graphite, it has very low resistance. The difference is in the structure of the carbon! More research required...

I also made a vid of this. I'm told it sucks:

https://youtu.be/Wex_yKfrTo4

Metal Contest 2016

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Metal Contest 2016

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    68 Discussions

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    ysnipe

    2 years ago

    I guess I'm missing something... I think I've made this more than a few times already... a couple of times in a toaster oven during a phone call... on a grill when a hamburger bun got left behind... Sorry but this is just burnt bread.... Why go to the trouble of making a steal box to burn it in, a gas grill or toaster oven will do it just as well... Or if you don't want the smells just put in in your oven when you turn the oven on the clean cycle.

    7 replies
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    Greymaseysnipe

    Reply 2 years ago

    Pyrolizing is the burning in the absence of Oxygen. The Argon doesn't make is special, but it DOES replace the oxygen in the chamber. The oxygen would be burned off pretty quickly in a sealed chamber, but in a toaster, the resupply would lead to a lot of CO2 (where the oxygen mixes with the Carbon in the burn down process) which is very different in behavior than CO2. So this LOOKS like burned bread, and it IS, but in the absence of Oxygen - so it is C, not CO2. "Brown's Gas" is the flammable byproduct that is giving the yellow flames mentioned. I hope that helps.

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    UdonGreymase

    Reply 1 year ago

    Yeah, I don't think that's Brown's Gas - water that's been electrolyzed into hydrogen and oxygen is referred to by that name.

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    johnny3hGreymase

    Reply 1 year ago

    I have seen "Brown's Gas" referred to in other posts here, and am compelled to illuminate the error. The gas released in the pyrolization [sp?] process in this 'able has NO relation to Brown's Gas [a stoicametric mixture of Hydrogen and Oxygen resulting from the ELECTROLYSIS OF WATER!].

    The gas produced by pyrolization IS NOT Brown's Gas!

    Please forgive my misspellings; it's been over 40 years since my last chemistry class.

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    Greymasejohnny3h

    Reply 1 year ago

    Yes! Thanks! I actually was aware of that, but had been reading about Brown's Gas around the time of the comment and was in a hurry and goofed! Thanks for catching it all this time later, johnny3h!

    Science...if we are wrong, we admit it!

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    tonymengelaysnipe

    Reply 2 years ago

    not the same thing, If you notice he used argon in the heating process, it changes the bread into something else entirely

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    Greymasetonymengela

    Reply 1 year ago

    I don't think it is any magic property of Argon in particular, as much as it is that it replaces the oxygen in the container. The paint can with the hole works because the outgassing of the bread and early burning likely burns out the oxygen and creates positive pressure keeping a sufficient amount out to cause the bread to burn with oxygen...same as making char cloth or biochar

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    danrulz98ysnipe

    Reply 2 years ago

    Yes, its bread with everything but the carbon burned out of it, you could make it in a toaster or oven as well. AvE just likes going overkill ;)

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    PitStoP

    2 years ago

    How long will the foam/burnt toast will hold up under the high heat? I'm in the process of building an pizza oven and was wondering if this will work for insulating the dome. Thanks for the Instructable.

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    electricavemanPitStoP

    Reply 1 year ago

    Well, I left some charcoal on top of a wood heater one year in a mortar (a ceramic bowl used for grinding). By the end of the winter the carbon that was ground into the ceramic had completely disappeared. The top of the heater stayed above 400 f for about 7 months.

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    SebaM1PitStoP

    Reply 2 years ago

    I was thinking of doing the same thing with nicrome wires andwas wondering if I could use the same nicrome wires to burn the bread

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    johnny3h

    1 year ago

    This same process can be accomplished much more simply with a clean paint can and lid, with a nail-hole punched in it, and burned in a small fire in the yard!

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    bitterbug

    1 year ago

    Just finished making some in a paint can, but it mostly curled up as it shrank. But this was fresh from the bag. For the second run I'm putting slices in the dehydrator to create flat, dry pieces before they even go into the can :D

    ME TOO... MY LOVELY WIFE ACCIDENTALLY LET A SLIDE OF BREAD INTO THE TOASTER FOR LONG TIME AND I FOUND CLEARLY THAT SHE DID A SUPER CARBON FOAM... LOL!!!

    SO ENJOY SCIENCE AND BE HAPPY EVERYBODY MY FRIENDS OF INSTRUCTABLES!!!!

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    rhgrafix

    2 years ago

    I've made this in my toaster before, accidentally, I must tell my girlfriend that I was making carbon foam, she will be impressed!

    Rambo

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    gh426

    2 years ago

    Isn't this also BIO-CHAR?? I see folks cooking very dry wood, supposedly any organic schmoo will work, and they get pitch, tar, etc seperated from it, vs burning it off and viola edible BIO CHAR, they also grind it up add worm casings, flour etc and make rich dirt with for to make Veggies / fruits

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    hugbear

    2 years ago

    So the pyrolisis removes all the organic components, leaving behind only minerals and carbon - making sure the carbon does not combine with oxygen at high temperature and burn. My question is: once the foam is removed from the container and placed in free air, what keeps the carbon from burning with the oxygen in the atmosphere when exposed to a flame?