16 replies to this topic

[NightHawkInLight]

Ok here's a topic that could cause a change in either how i do things or in the way others go about making charcoal. I have made my own charcoal for the entire time I've been into pyrotechnics (Close to 8 years now)
The thing is, i have never cooked the wood without oxygen in a closed container like most people do. In fact i have done the exact opposite. I have a large metal box i constructed with an open top and a 4" diameter vent at the bottom. When i cook my wood i fill the box completely and ignite it with a leaf blower aimed at the bottom vent. This burns all the wood and turns it into a thick pile of coals on the bottom right quick.
With the leaf blower running it keeps the pile white hot for a good half hour to 45 minutes, until I suspect all the wood is completely burnt.
I then proceed to spray down the coals with a hose. I have fairly pure water here, so i don't believe I'm contaminating the charcoal with that. I then dump all the charcoal onto a sieve and wash it throughly to remove any ash that wasn't blown away by the leaf blower (most of it is). After drying this charcoal has always burned quite fast in my black powder and has provided me with a good way to make large quantity's of various charcoals.
The reason i believe this has worked for me is the washing step i take. Any ash created that is not water soluble is fine enough particle size to fall through the sieve. Without ash contamination, is there any property of the charcoal that is taken away by cooking the wood like this?
I very much like being able to make large quantity's of willow, grapevine and pine charcoal like this, and it seems to work well for me. I would however like to know if I'm somehow missing out on better preforming compositions. As one who as never bought commercial charcoal i have nothing to contrast this to.
Thanks
-Ben

[FrankRizzo]

What you lose is some of the reactive oils that re-condense back on the pyrolysing wood inside of an oxygen-starved retort. These reactive oils (along with charcoal density) are what make good charcoals fast burning. With your method, you're basically cooking down to mostly carbon with a very small bit of the higher boiling oils.

BUT, if the BP that you create this way works well for what you're doing with it, don't worry another minute about it. Many people get too caught up in the "is my BP the fastest" fetish, and forget to enjoy the art.

[NightHawkInLight]

Hmm, that's about what i figured it could do. But yes it does work very well for me, my BP is plenty fast for lift and breaks, and even salutes if i want a deeper boom than flash. I may however still try the slow cooked charcoal at some point to see how much of a difference it really makes. Thanks for the reply
-Ben

[NightHawkInLight]

Ok so here's a question, has any research been done to see what oils etc. speed up the burn and how they preform as additional additives?

[hst45]

Nighthawk, in regards to your technique, no matter how unorthodox, if it works, no problem. There is no "right" way, or "best" way, there is only what works for you, and so much of what we now take for granted was created by folks who simply did what they thought best. My only thought is that your method might lead to inconsistency, since you're relying on your observation about when to quench the pile.

In my particular situation I heat my house with a wood stove, so I have a ready source of heat (for at least 6 momths of the year, anyway). I made a 6"X24" homemade steel retort with a screw-cap on one end, and about fifty 1/4" holes along the bottom. I fill the thing with poplar/maple/white pine/newsprint/willow and toss the thing onto the coals, with the holes down. The fire evaporates the water, then drive the oils and alchohols down through the holes, where they ignite and add to the heat. With the holes down there is no opportunity for oxygen to enter the retort and consume the charcoal. I remove the retort from the fire and set it in a sand box I keep near the stove, still holes-down so no oxygen can enter, and let it cool down. This has given me a consistant product from batch to batch, with the exception of newsprint. Newsprint has proved to be some of the best and some of the worst stuff I've made. It seems particularly problematic in BP rocket formulas, where i've abandoned it completly in favor of maple charcoal. I have no scientific reason for this, it's merely my experience.

Christ, I'm chattering-on like a loon. I noticed that I also spelled "alcohol" incorrectly, which is udoubtably due to my consumption of same. This is not a night to combine fuels and oxydizers! The ability of a pyro to count to ten on ones fingers is inversely proportional to his blood-alcohol level, so tonight I'm leaving behind the 6" mortars in favor of the 16 oz. margruerittas. Ethanol, have mercy on my soul............

[NightHawkInLight]

Haha, thanks for the comment. Your method is something i may try at some point. You're right that i may get inconsistent results, but i have gotten quite good at getting similarly preforming charcoal. It also helps that i make it in around 8 pound quantity's, so if i got it right it'll last a while.
I'm still interested at what oils could modify the burn rate of the charcoal. If they were readily available it could be an interesting thing to experiment with tigertail type stars and the similar. I imagine it would have some beneficial effects on tailed stars, and nearly any other composition containing charcoal.

[qwezxc12]

...I'm still interested at what oils could modify the burn rate of the charcoal. If they were readily available it could be an interesting thing to experiment with tigertail type stars and the similar. I imagine it would have some beneficial effects on tailed stars, and nearly any other composition containing charcoal.

Hmmmm....I've thought on the same subject; namely "spiking" generic, mixed source charcoal with fractions of various VOCs and making test batches of some simple charcoal streamer, like Chrys6, and evaluate the difference (if any).

My plan was to take a control batch of ~800g of un-milled cowboy charcoal, process it through the old meat grinder, then ball mill into airfloat. I would portion out into 100g batches and add, say .25% - .5% of:

Mineral oil
Naphthalene
Kerosene
A few types of motor oil (why not?)
WD-40
Maybe Olive or Vegetable oil

I would re-mill the mix to fully integrate the volatiles, then make and bind the stars as normal. Hopefully the small addition of VOCs will not hamper the action of an aqueous binder.

I’ve not read any purposeful adulteration of charcoal in other tests. Has any enterprising soul already done this?

[NightHawkInLight]

That was my thinking for a test. that would be interesting, maybe worth my time to test. The only thing i've done involving any of those was with added naphthalene to charcoal for fireballs.
It seems easy enough to test, i may try milling up some chrys6 and adding some of the oils to test amounts. Another thing that might change results could be addition of the oils before and after the charcoal is in a composition. It would be easier and faster to test if you could add the oils to the entire composition, at least for me because i like to mill the components together throughly. Therefore you could mill a very large batch of chrys6 instead of many small test batches over the course of at least a week.

[qwezxc12]

I was thinking along the lines that the "tail" in any charcoal comp is the burning, under-oxydized carbon, so I wanted to really work in the additional volatiles into the particles of the charcoal by milling. I'm not sure if adding the VOCs to the mix would achieve that - potentially coating the S and KNO3, rather than getting into the pores of the charcoal. Who knows? You might achieve the same result with less work.

If you did it that way, you should do a batch adding the extra organics, before and after mixing the comp, to see if the results vary.

P.S. - if you do some trials, don't forget to try Patchouli or Sandlewood...Hippie friendly fireworks!

[NightHawkInLight]

Alright well i have been milling 150g of TT type star comp with an added 5ml of olive oil to premilled charcoal for the past 8 hours or so. The only problem i've had so far is the milling, the comp likes to stick to the walls after a short time. It burns beautifully dryrammed into a pellet at the moment with a soft pinkish flame and bright but small and long lasting sparks. I'll be cutting stars with it tomorrow and will be doing some tests as soon as they dry. Hopefully i'll have a video up by tuesday.
For now if you're interested the comp i'm testing with is...
60 kno3
30 ash charcoal
10 sulfur
+ 6 dextrin
+ 3 1/3rd ml of olive oil (this is an odd measurement because i added 5ml to 150g, also i pretreated the charcoal with it so this was added before the rest was milled)
alright, well more later

[qwezxc12]

Did you reserve any untreated TT mix to compare it too? I only ask because everyone's is different depending on charcoal and milling process. It would be good to see yours in a side-by-side comparison. My experiments will have to wait a bit...I'm currently in the middle of batch testing Shimizu's Willow formula with added amounts of lampblack and Al.

I'm definitely staying tuned, though.

[NightHawkInLight]

i did not reserve any of the original batch, but i will be putting some untreated comp in the mill as soon as the other stars are cut. I was somewhat surprised to find that the dextrin still activated with what i thought was far to much oil. The water is a little bit harder to work in, but that's the only difference i found.

[NightHawkInLight]

Allright i got a video up, it describes my tests:

The only problem i had with the stars was an obnoxiously long drying time, i just put them in a toaster oven at 200 degrees F for 45 minutes to dry them out so i could fire today. The pink in the stars was beautiful, it's a shame the camera didn't pick it up. Looked great with the golden tail.
I'll try some small shells with them later in the week

[moonshot]

In regards to your method of making charcoal it seems to me that your losing a lot of usable fuel by actually burning your wood rather than baking it. Also the extra step of washing the ash off the usable charcoal is not necessary if you bake it since you will not produce ash in the baking process. Making true charcoal by baking is technically counter productive because it takes more energy to carbonize the wood than you get back from burning the charcoal.

[Mumbles]

I would go ahead and say that the method of drying stars is pretty unsafe. Patience is a virtue. I'd go to 100F, and really not much higher when drying anything. Applying heat in that manner willl often result in cracking of the stars if not fire. I'd be much more careful in the future. Those temps can cause ignition without a doubt.

As far as the method, it's not new. It is how it used to be done, and may possibly still be done on a large batch process. Well, one used to light the center of the wood, let it burn down so much, and then smother it with a lid, or a large mound of earth for a few weeks to fully carbonize the wood and such. A retort type of method does indeed give more product, and theoretically speaking, a slightly less contaminated one as not all ash is soluble in water. Still most of that should be washed away anyway.

If it works for you, and you literally have wood to burn, I say go for it though. However with most of us with a limited amount of good charcoal wood, a retort type method makes sense.

[tentacles]

Mumbles: Shimizu describes stars drying in the sun as reaching 160F in FAST, as I recall. Still, the open and red hot element is too much pucker factor for my taste, even left outside on a driveway or something.

I wonder if the pink color is comparable to those pink glitter stars they had at the grand public display? Those were great!

[NightHawkInLight]

i understand the concern with drying stars under any kind of artificial heat, but i happen to have a toaster oven that i use for nothing else. i just stick it outside on pavement with nothing flammable around.
I think for now i will keep my charcoal method, although i am curious to see how my grapevine/willow mix compares to the same mix made in a retort.