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Greetings, fellow carbon-based life forms! I was reading in a couple of different threads about the uses of activated charcoal and how you really should have some in your emergency first aid kit; and about how it's really hard to make. Actually, it isn't all that hard to make, just tedious, and not something you want to do in the basement.

Charcoal is made from heating wood in a low-oxygen environment. The heat drives off all the moisture and hydrocarbons (wood gas) in the wood, leaving just carbon (charcoal). To activate the charcoal, you treat it with acid and heat it again.

Check out YouTube and you'll find half-a-dozen or so videos on making your own charcoal cooker. Some of these are just for making charcoal (very useful if you like to pound dull steel into sharp, pointy things) (also useful if you want to make your own black powder, but that's another post); others are primarily for making wood gas to run cars and trucks.

The common features are: 1. being able to seal up the container so that air doesn't get into the oven (otherwise the wood burns, not chars), and 2. a small hole or tube to allow the wood gas to escape so you don't have a pressure bomb.

If you're making activated charcoal, in the end you're going to want to grind the result into a powder, so start with small pieces of wood. I know someone who swears by old pallets. They're easy to cut into small pieces and they char very well. (If you're planning on using the activated charcoal for filtering water, apparently coconut shells are the best. Where to find large numbers of coconut shells in, say, Minnesota, is YOUR problem.)

Put the wood into your cooker, seal it up, and light a fire underneath it. As it heats, you'll see steam/wood gas come out of the small hole. After the steam starts coming out, cook the wood for at least 4 hours -- you'll have to experiment to see how long it will take depending on the amount of wood, etc. After 4 or 5 hours, take the cooker off the heat and let it cool naturally. You'll want to make sure it's thoroughly cool before opening it because otherwise the char inside will burst into flame when the oxygen hits it.

After it's cooled and you've opened it up to expose the charcoal, test a few pieces to make sure they've charred all the way through. If not, you can still use that batch for burning but not for making into activated charcoal; and remember to cook it longer next time. If all you're looking for is charcoal to make black powder, or charcoal to burn in your forge, you're done. Otherwise, read on.

Here's where it gets tricky. Get some battery acid from your local auto supply store. Using a glass pan, plastic or rubber tongs, rubber gloves, goggles, and all the other safety equipment you can muster, pour the acid into the glass pan. Then carefully place each piece of charcoal into the acid and let it soak for four or five minutes. Remove each piece from the acid, let it drain a bit, then put it back into the cooker.

When all the pieces have been treated, seal the cooker back up, put it back on the heat, and cook the charcoal for another 4 hours or so. Let the cooker cool, open it up, grind up the pieces, and you've got activated charcoal.

If you're not into all that waiting and cooking, you can buy activated charcoal at a tropical fish supply store (make sure it's JUST the charcoal, and nothing else.) If you're planning on using the charcoal for water filtration, etc., though, you may find it more cost effective to burn your own.
 

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Okay, just a suggestion or two:
1) this stuff isnt as activated as store bought charcole, so adjust your quantities accordingly. 50% less porous is where id aim, though its probably way too low.
2) dont just make a hole to let out wood gases! use a bit of pipe to re-route the gases back into the fire; its basically coal gas, and burns really hot. on that same not, dont breathe in the fumes.
3) generally, charcoal is ready a bit (30 min?) after it stops giving off coal gas (see post two)
 

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Discussion Starter #3
Replies:

1. I don't know how activated the end product is. As with any other home-made product like corn likker or babies, there's a lot of variations possible. You're sacrificing the precision of milliliters and precise temperatures for something that gets it done without costing a lot.

2. If I could take a class in welding, I would. Then I'd make a cooker that routed the gas back into the flame. As it is, though, my version of a cooker is a clean paint can with a nail hole in the lid. It doesn't make much, but it makes enough for me.

(Of course, now that I'm thinking about it, I could put the nail hole in the bottom of the can and prop it up so the output feeds into the fire. Or just flip it upside down. Hmmm...)

3. One reason I'm using the paint-can cooker is that right now I'm still experimenting, not ready yet for any kind of "large scale" production. As it is, the times I've tried relying on the appearance (or lack thereof) of wood gas my results have been inconsistent. It's happened often enough that I would have sworn no more gas was appearing, then after cooling the cooker large pieces of the wood aren't charred all the way through, that I just use a timer: cook for 4 hours while I'm in the area doing other stuff; then take it off the fire and let it cool for an hour before opening it. I've had good luck with that timing, and "overcooking" the wood doesn't seem to hurt it.
 

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If you're not into all that waiting and cooking, you can buy activated charcoal at a tropical fish supply store (make sure it's JUST the charcoal, and nothing else.) If you're planning on using the charcoal for water filtration, etc., though, you may find it more cost effective to burn your own.
Yeah, I was going to suggest that very same thing.

I just think it would be easier to have on hand ready to go in bulk than have to buy acid and cook your own post SHTF.
 

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Yeah, I was going to suggest that very same thing.

I just think it would be easier to have on hand ready to go in bulk than have to buy acid and cook your own post SHTF.
Not honestly sure what the point of the acid post-burning is, i admit.

I know people use acids before the combustion because you can then use a lower temperature and for less time yet achieve the same results.

You dont actually need H2SO4 (battery acid) though. You could use HCl or NHO3 or whatever else is at hand i would think...
 

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Discussion Starter #6
Not honestly sure what the point of the acid post-burning is, i admit.

I know people use acids before the combustion because you can then use a lower temperature and for less time yet achieve the same results.

You dont actually need H2SO4 (battery acid) though. You could use HCl or NHO3 or whatever else is at hand i would think...
The key to activation is to make the charcoal have millions of little "pits", which dramatically increases the surface area of the charcoal for a given volume. The acid creates the pits. When you're burning your own, it's easier to acid-treat your charcoal after your first burn. Pre-burning (treating the wood with acid) is what the commercial manufacturers do (since then you can get it in one burn time rather than two), and it involves a lot of chemical reactions that are hard for a DIY'er to handle.

You don't NEED battery acid, but it's a LOT easier to get battery acid than to get HCl (Hydrochloric acid) or NHO3 (Nitric acid). You can get battery acid off-the-shelf at an auto store, whereas the other acids have to come from chemical supply stores, most of which won't sell to the general public.
 

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Hmmmm... I don't know about the chemistry behind this, but I don't know that I would like to use any "Acid treated activated charcoal" to filter my water or in my stomach to help me with poisons. I can't see how the acids would cook off completely at low temps or be completely infused within the charcoal. Injesting battery acid isn't my idea of good eats. But heck I could be wrong on this.
 

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Hmmmm... I don't know about the chemistry behind this, but I don't know that I would like to use any "Acid treated activated charcoal" to filter my water or in my stomach to help me with poisons. I can't see how the acids would cook off completely at low temps or be completely infused within the charcoal. Injesting battery acid isn't my idea of good eats. But heck I could be wrong on this.
Any commercial activated charcoal you buy will have been treated with acid at some point in the process. The commercial products use low temps because it's less expensive; that also means they have to take a long time to process the carbon into activated charcoal.

If you're using battery acid (strong sulfuric acid) the chemical reaction SHOULD be like this (it's been some time since I've taken college chem): H2SO4 + C = H2 + S02 + CO2. As the acid eats pits into the carbon, it generates hydrogen gas, sulfur dioxide, and carbon dioxide.. Keep adding heat and you keep creating sulfur dioxide and carbon dioxide. Eventually, all the sulfur cooks off
 

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Okay, as someone who has made lots of charcoal in the past here is the best charcoal maker you can get for the money:

Step 1: Get one 55 and one 35 gallon steel drum (with lid). Also get two pieces of thick rebar.

Step 2: Cut a 12"x12" square out of the 55 gallon drum on the side at the bottom. Also cut four holes above the square cutout (these are to pass the rebar through so you can rest the 35 gallon drum on them.).

Step 3: Poke about 9 or 10 holes in the bottom of the 35 gallon drum to let the gas out. Then rest it on the rebar inside the 55 gallon drum.

Step 4: Fill the 35 gallon drum with whatever wood you want to char and seal it up. Fill the 55 gallon drum up with as much scrap wood as you can and light it.

Step 5: Keep it burning for hours. When you're done, pull out the rebar so the 35 gallon falls into the ashes (will cover the gas holes) and let it cool. You now have some charcoal.

The gas will blow right into the fire in the bottom of the 55 gallon drum and burn up. It's a very good little coal maker.
 

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(If you're planning on using the activated charcoal for filtering water, apparently coconut shells are the best. Where to find large numbers of coconut shells in, say, Minnesota, is YOUR problem.)
Mabey a swallow droped it I dont know if it is African or Europian though :D:

But yeah to get the acid just go into a homedepot or a lowes tell them you need muratic acid they usually sell it in two one gallon jugs in a box for 10 bucks or somthing A WHOLE LOT CHEAPER then the batterie

Plus if you need to make Chloreine gas you can always use what you got left of the acid put it in a bottle and throw some Aluminm foil in and put a ballon ontop

Though I dont really know what you would need chlorine gas for :xeye:
 

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very interesting great thread to start.

i would also caution to use food grade items if going to be used internally.

residues from toxins are generally left behind in finished product.
 

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2) dont just make a hole to let out wood gases! use a bit of pipe to re-route the gases back into the fire; its basically coal gas, and burns really hot. on that same not, dont breathe in the fumes.
Maybe I'm missing something, but couldn't this cause the flame to go back into the reservoir?
 

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Mabey a swallow droped it I dont know if it is African or Europian though :D:
I´d like to that swallow...:D:

Does it wotk with any acid? There are acids you could manufacture and purify yourself. I´m thinking long term SHTF.
 

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How about apple cider vinegar? It has about 5% acetic acid, although a rather weak acid I wonder if it would be strong enough to work.
 

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How about apple cider vinegar? It has about 5% acetic acid, although a rather weak acid I wonder if it would be strong enough to work.
I would think citric would work a little better or even tomato paste tomato paste will eat through aluminum but it might not work so well on making active charcole

I can tell you from experince that muratic has a very very strong Lime flavor
I had some spalsh onto my toungh one time while I was cleaning bricks
 

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DO NOT REACT HCL/muriatic acid with carbon

I stumbled across this forum while researching water filtration, and felt the need to inform you on the possible effects of reacting HCl and C.

These are some possible results of this reaction:
Reacting Carbon with HCl could produce
  • Carbon tetrachloride (Freon) - potent greenhouse gas
  • Trichloromethane (Chloroform) - CNS depressant, converts to phosgene in the presence of oxygen and heat
  • Chlorohydrocarbons -some are highly toxic, some are greenhouse gasses, many are flammable.
  • Various hydrocarbons - toxic, flammable, and potent greenhouse gasses
  • Chlorine gas - toxic
  • Hydrogen gas - flammable

HCL almost completely dissociates in H20 into protons and chloride ions. Both of which would readily bind to carbon to form all kinds of nasty compounds.

Please, do not do this, and leave chemistry to the chemists.
 
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