Charcoal: overdone or underdone?

[Weasel]

I just made about 200 grams of Pine charcoal with the bedding you can get in pet stores. The only problem is that it insulates itself, so you have to open the lid halfway through the process of making charcoal and stir the flakes around. You then have to close the lid quickly and seal any holes until the inner fire stops. So my charcoal has about 5% burnt material when it is done. I still like using the flakes becuase you can then put them right into your mill without having to crush large chunks, and they charcoal much quicker than big chunks, even with the insulating factor. If you don't stir the charcoal, you will either end up with over or underdone charcoal. When I first started making charcoal i used big chunks of wood, and because I was inexperienced, I would often end up over or under doing it even then.

 

Now that i have said all this, I also want to ask if it is actually possible to over do charcoal. I accidentaly let my charcoal cook for about half an hour after it stopped smoking, and I consider that to be over doing it. But my charcoal still looks just fine, it is not white or ashy, which makes me wonder if you can cook charcoal too long.

 

Here is a sample of my "overdone" charcoal:

 

 

So my question is this: If you could only choose between over or underdoing your charcoal for making blackpowder, which would you choose?

note that I am talking about charcoal for fast powders, for spark effects i would go with underdone because the bits of raw wood would actually add to the spark effect. But for blackpowder I personally feel overdone charcoal would work better, if there is such a thing as overdone. I am intrested to see what the pyro community thinks about this....

[Ralph]

I just made about 200 grams of Pine charcoal with the bedding you can get in pet stores. The only problem is that it insulates itself, so you have to open the lid halfway through the process of making charcoal and stir the flakes around. You then have to close the lid quickly and seal any holes until the inner fire stops. So my charcoal has about 5% burnt material when it is done. I still like using the flakes becuase you can then put them right into your mill without having to crush large chunks, and they charcoal much quicker than big chunks, even with the insulating factor. If you don't stir the charcoal, you will either end up with over or underdone charcoal. When I first started making charcoal i used big chunks of wood, and because I was inexperienced, I would often end up over or under doing it even then.

 

Now that i have said all this, I also want to ask if it is actually possible to over do charcoal. I accidentaly let my charcoal cook for about half an hour after it stopped smoking, and I consider that to be over doing it. But my charcoal still looks just fine, it is not white or ashy, which makes me wonder if you can cook charcoal too long.

 

Here is a sample of my "overdone" charcoal:

 

 

So my question is this: If you could only choose between over or underdoing your charcoal for making blackpowder, which would you choose?

note that I am talking about charcoal for fast powders, for spark effects i would go with underdone because the bits of raw wood would actually add to the spark effect. But for blackpowder I personally feel overdone charcoal would work better, if there is such a thing as overdone. I am intrested to see what the pyro community thinks about this....

 

under done still has all the volatile species in it and no ash making it better i always go for under done

 

 

 

[dagabu]

I guess you will just have to try some from each under done and over done and see which works better for your needs. When I am cooking saw dust (or chips) I like to put about 5 paper towel tubes into the pot first and then pack in my wood, I pull the tubes out after it is all packed in. The holes stay and I dont have to stir.

 

It works for me!

 

D

[50AE]

Slightly underdone, when there is very little smoke coming from the hole.

You don't want to make it much underdone, because it will be harder to grind.

I've never suceeded making overdone charcoal.

[Mumbles]

It's pretty much impossible to make overdone charcoal without setting out with that goal. You would have to accidentally leave it out on the fire overnight at white heat to really even start to affect it. I've heard something on the order of 1000C for 24 hours can start to convert it to a graphitic structure, which would make it less reactive.

 

As far as no ash in cooked charcoal, that is funny. Extract it with acid if you want, but you will find anywhere between 5 and 20% ash in your properly cooked charcoal. Do you think those minerals just appear from the air when you open it?

[QED4803]

I have virtually no expertise here, so file this under "things to be considered" rather than "good advice", but I have also pondered these same issues and come up with the following working model:

 

Some part of the reactive nature of various charcoals is known (or at least believed) to result from the volatile hydrocarbons left behind during destructive distillation (cooking). This would seem to indicate that overcooking might, at least in some cases, diminish reactivity by driving off more of these volatiles. Ash, on the other hand, is pretty much a negative component for our purposes, being at best a non-reactive filler, at worst a contaminant which may cause undesireable reactions. Of course the ash is still present in the undercooked product, it's simply structurally bound into the charcoal, so not visible. The ash we see is the result of the carbon being oxidized, leaving only the ash component. This visible ash can, in my experience, be easily rinsed out with water which I presume will not affect the desireable hydrocarbons. So the quandary in my mind becomes one of balance: Overcooking likely drives off more of the volatiles; undercooking leaves uncooked wood which needs to be sorted out somehow and probably remains to some degree in the final product. The ash, I think, becomes a virtual non-issue in this process, as the ash rinsed out is proportional to the amount of carbon lost to oxidation.

 

As mentioned by someone else earlier, the bound ash might be removed with acid, and this might be worth exploring, though I have no idea what the solubility of the "volatiles" might be. Nothing I've seen in the limited pyrotechnic literature I've perused has addressed these considerations empirically, but I would love to see data on cooking times and temperatures vs. measurable reactivity (maybe pyro golf). As Dave said: "Try everything and see what works for you."

[dagabu]

Pyro-golf! Mmmmmmmm.

 

A decade ago when I was playing with my first retort (nothing serious) I found that my BP rockets would fly better when the charcoal was completely cooked and not overcooked. I will leave it to Mumbles to explain why that is though.

 

I had one batch that I thought was cool and so I popped the lid and it started on fire, I put the lid back on and let it cool for an entire 24 hours before taking the lid off again. I had a mess! Half of it was ash and the other half was charcoal.

 

I dumped it all into a colander and rinsed it off letting all of the stuff that wanted to go down the drain do so. I set it in a plastic bucket to dry and forgot about it for the winter. When I ground it up the next spring, it worked as well as the stuff that had cooked cleanly.

 

FWIW

[Bonny]

I dumped it all into a colander and rinsed it off letting all of the stuff that wanted to go down the drain do so. I set it in a plastic bucket to dry and forgot about it for the winter. When I ground it up the next spring, it worked as well as the stuff that had cooked cleanly.

 

FWIW

 

I've done the same thing in the past, a simple rinse and the charcoal seemed to be just as good as the "properly cooked" stuff.

[Arthur]

One of the Russian authors offers a table of temperatures vs function and there are some changes.

 

Under cooked charcoal is too hard to mill and brown ish.

minimally cooked it is soft and black and crumbly, the powder will be fast and sensitive.

over cooked it is black and the powder made will be less easy to ignite.

 

Charcoaled to 300c should be good and have a 30% yield from plank dry wood

Charcoaled to 500c the yield will go down to 23%

charcoaled to 1000C the yield will be about 15% and the powder will be insensitive.

[Weasel]

I guess you will just have to try some from each under done and over done and see which works better for your needs. When I am cooking saw dust (or chips) I like to put about 5 paper towel tubes into the pot first and then pack in my wood, I pull the tubes out after it is all packed in. The holes stay and I dont have to stir.

 

It works for me!

 

D

 

 

That's a great idea D! I'm definately going to try that...

 

The reason I have recently questioned if overdoing charcoal is possible is because lately all my batches of BP have been slower than normal. I have to add some balsa charcoal into my BP just to get my desired speed. The only difference I observed is that I had been letting my pot of charcoal cook longer than i normally do, so I assumed I must be overcooking it.

 

It's hard to believe properly cooked charcoal could have 20% ash in it and still produce usable BP, but you have a lot more experience than me, Mumbles.

On pyroguide in the charcoal tutorial it says that "It is important to make sure you don't heat [your charcoal] for too long." This led me to believe that it is easy to overdo charcoal, but according to you it takes hours to overdo it.

I may just try and wash my charcoal too, and see how much that helps.

Edited March 29, 2010 by Weasel

[dagabu]

Honestly, I am way to high strung to let go one minute past being done. I watch the smoke like a hawk and when it is gone the retort comes off the fire.

 

Good luck and let us know how it goes!

 

D

[Arthur]

Urbanski Vol 3 chapter 3 p334 et seq gives hugely detailed descriptions of charcoaling and the structural changes in the wood during charcoaling. Basically cooler charcoaling yields sensitive powder but not as powerful and slightly hygroscopic. Hotter charcoaling yields less charcoal and harder ignition but more power when lit and less water absorption.

[Mumbles]

There are a few schools of thought on the matter. I am actually trying to locate an article on charcoal in gun powder, and a comparative study on wood variety, cooking temperature, and cooking time. We have it on campus, but I am going to have to do some digging to find a copy as it's not electronic.

 

Many only look at one factor, such as the volatiles. It is true that wood cooked at lower temperatures tend to be a bit more reactive. It is said if you can get the rainbow of volatiles on the surface that it is supposed to be the best available. I can never do it deliberately though.

 

Urbanski's view is that there are radicals produced during pyrolysis. You go from lignin and cellulose, and essentially shread the bonds, which leaves jagged ends that are quicker to react.

 

Other things like carbon and ash content will effect things too. Carbon content is primarily determined by cooking time and temperature. It can actually vary by about 15%.

[Bonny]

Many only look at one factor, such as the volatiles. It is true that wood cooked at lower temperatures tend to be a bit more reactive. It is said if you can get the rainbow of volatiles on the surface that it is supposed to be the best available. I can never do it deliberately though.

 

Interesting. I've seen the rainbow on the surface many times, but never thought anything of it.

I just cook mine until no smoke comes out the top, the time varies depending on the wood, the size of the fire, and how much I'm cooking.

[Ralph]

isnt the point at which you see rainbows and such still "underdone" as there is still some smoke coming out (thats what I class as under done anyway)

[Mumbles]

Well, it depends what you classify "done" as. I think of it as when all of the wood has been converted into charcoal. However, the more one reads about this topic, the less that actually means. There are many levels of done, as there are many kinds of charcoal. There are a wide range of carbon and volatile contents that will behave like what we think of as charcoal. They're all black, easily crushable, will burn fiercely in BP, etc.

 

Usually when I'm cooking charcoal, I look for the thick white smoke to stop coming out. If you really take a look, there is usually a very thin blue smoke coming out after this though depending on how hot you were cooking it. The white is water, CO2, volatiles, and probably a host of other things. The blue smoke is heavy on the volatiles. It makes sense to me that if you cook it at a relatively cool temperature, you can still get that rainbow, yet have fully cooked wood in the sense that it will crush completely. When cooking in a campfire, it usually gets pretty hot and I can never tell when the thin blue smoke is only there. I have, in a pinch, used a cheap electric hotplate to carbonize wood before. It's weird to think it would get that hot, but if I hadn't done it, I would have never believed it. I can't imagine it was much hotter than 500F/260C. Now that I think about it, that was always my most potent BP. There were so many other factors though that I really can't make any judgements.

[dagabu]

I stop when the smoke diminishes and you cant light the smoke with a torch.

 

D

[PyroMan LTU]

Hello, people,

 

Made some black alder charcoal this weekend for new season. worked out great, I tried this time, in a huge amount. I cooked in a 150l barrel (filled up with wood pieces) inside a 200 liter one. I didn't want it to burn too fast so I poked only two holes at the botom of the big one, which was eaqual to nothing so fairly all the oxigen for the combustion was picked up from the top of the barrel. That's why it burned so poor. However it was enough, I believe, becouse the final charcoal from the inner barrel looked very good. Brittle & light. The whole cooking took around 4 hours. And the yield... From 150l barrol I've got 4.15kg of charcoal. Equal to around 30kg of BP and 10kg of charcoal stars. So few questions

 

1) it took 4h, If I poke more holes and give more temp, how quick should it be prepared then? (or this is normal for big amount)

 

2) is this a good yield?

 

3) I pulled the barrel out when the gas from the inside finished runing, shouldn't this operation be done sooner?

 

4) How many holes do you guys recomend to make at the bottom for further operations?

 

5) I cooked in a oil barrel and after drilling holes in the beginning some iron pieces may be remaining inside (I cleaned it as much as possible) does this run any risk for BP ballmilling? BTW, I picked inly lumps of chatcoal, I didn't take the smaller pieces out of the bottom.

 

6) This is my BP charcoal. What do you suggest form aspen and birch to be use for stars? I've checked pyroguide, but no info about birch.

 

Some photos:

 

Preparing http://i326.photobucket.com/albums/k424/fastzone24/Atvaizd007.jpg

150l barrel http://i326.photobucket.com/albums/k424/fastzone24/Atvaizd008.jpg

After cooking http://i326.photobucket.com/albums/k424/fastzone24/Atvaizd030.jpg

Bag of finished charcoal compared to my dad's old trainer http://i326.photobucket.com/albums/k424/fastzone24/Atvaizd032.jpg

Result http://i326.photobucket.com/albums/k424/fastzone24/Atvaizd033.jpg

 

Thank you for the awnsers!

 

Best Regards

 

PyroMan

[Arthur]

The good charcoal for pyro is soft light and fluffy. If it crumbles by hand it's OK. Edited May 10, 2010 by Arthur

[dagabu]

It looks great to me!

[PyroMan LTU]

Alright then

 

But I'm still waiting for an awnser for at least 3,5 questions and if possible all

[Mumbles]

It's hard to tell how good the yield is without knowing how much wood you started with.

 

I don't think more holes would make it cool any faster. If anything it may make it go slower, and give more ash. I wouldn't pull it out until the gases stop flowing out, or being flammable.

 

If you're worried about metal in your BP, which would be bad, pre-mill it to a fine powder, and screen it to remove any wood lumps or metal.

 

Black Powder Manufacturing, Testing, and Optimization lists aspen as a very fast wood. Lift suitable. It says nothing about birch.

[PyroMan LTU]

Thanks, Mumbles!

[jwitt]

Reading "aspen and birch" got me on the tree-remembering tip. A bit of internet reading reminded me- there is quaking aspen and bigtooth aspen. The wood of each is somewhat different- an article says one yields nice lumber and one only pulpwood. I wonder why that is? Wood strength? Knots?

 

Birch bark is good fire starting tinder, I think because it's high in volatiles. Of course that doesn't tell us anything about how the charcoal would perform...but I wonder what high-volatile woods make good BP or spark-producing charcoal? (Not counting conifers like pine) Poplar?

 

I don't think birch wood is terribly dense though, so I bet it's a "soft hardwood" and might have the cellular characteristics that (from my meager understanding) make good BP.

 

PS - Recently got a copy of Black Powder Manufacturing, Testing, and Optimization and it's a worthwhile book!

Edited May 11, 2010 by jwitt

[Fly]

Has anyone of you tryed cedar coal?I have heard it's good but don't know?:blush:Now here is a good read

on charcoal.http://www.musketeer.ch/blackpowder/charcoal.html

 

Fly