"Charcoal," she retorted

[Ohio]

To continue my adventure in Bad Blacksmithing, I need fuel. To get fuel I had to either spend money (boo) or make a charcoal retort (yay), which sounds very self-reliant-y and xxxx until you realize you actually have to do it.

I looked at different designs, watched some videos, and read some stuff. I focused on James Hookway's design for a charcoal retort that sent the pyrolitic gases to feed the rocket stove used to heat the wood being turned into charcoal. I even bought his plans because honestly, he thought of some stuff I hadn't and credit where credit's due.

My neighbor got very excited about this project. A little too excited. He's an ok dude, just a serious pyro. And just when the weather again got very hot, he decided I needed to start building and I was baited with free material. I believe that is against international law---just giving somebody the xxxx they need to make something they weren't going to make until it was no longer 90+ degrees.

So my neighbor and I dug out some lengths of 5x7 and 6x6 1/4" tube, which he then proceeded to cut (badly) with his new plasma cutter. Then I got to use the plasma cutter and I was better at it than he was but still terrible. Later I thought there had to be some tricks or templates and sure enough, the internet showed me how to not xxxx so bad at plasma cutting. I filed that away for when I get my own plasma cutter because, dang, they are cool. xxxx xx xxxx stupid hacksaw.

I  welded up the firebox and we assembled the rocket stove at my neighbors. My fab partner promptly named it, "Rocket J. Stove." It's moments like this that really sustain a marriage.

My neighbor then gave me a stanky 55-gallon drum, lid, and clamp. It was only after I cut out the bits I needed to cut out that I realized the stanky drum and the lid did not fit. So my neighbor gave me another stanky drum, which was kinda annoying because these drums were pretty gross and the clamp for the lid that fit this one was rusted and would not move no matter how much bad language I used. Which was a lot.

I called it a day, and sprayed the nut and bolt with Deep Creep. Then I had some cocktails.

I got it all sorted the next day and cut the bits I need to cut, welded on a blow-off pipe, and of course, did more grinding. Do you know how easy it is to burn through the lid of a 55-gallon drum? I do.

Then came the rockwool insulation and some wire garden fence that I tightened up by using ratchet straps on the outside. And I wrapped it all in some aluminum flashing. I said it was to protect the insulation, which is true, but really I did it because it's shiny.

The assembled charcoal retort is named Burnie.

Burnie was all assembled and loaded up yesterday. I fired up this morning. Four minutes (I timed it) from lighting a single piece of newspaper in the rocket stove to a roar. After about an hour we had the gases from the wood being pyrolized feeding back into the firebox of the stove. It was pretty awesome because I never think anything I make is going to actually work.

After 3 hours, we were done.

It took about 1.5 to 2 5-gallon buckets of scrap to feed the rocket stove. We had to do some adjusting because I had forgotten to drill some holes in the removeable stack as an afterburner---whoops. I also need to get some high-temp silicone caulk to use to seal everything. I used clay (per James Hookway's instructions) but that was less than stellar. Everything worked, but we had flames sneaking out. They were pretty, but the rockwool got pretty smoked in some places and I'd like to have a cleaner burn for the sake of breathing, which I am in favor of.

Burnie got very hot. My non-contact thermometers hit their max, so over 888-degrees F. My neighbor kept saying next time I should fire up Burnie at night so we could see the cone of fire coming out of the stack. He also said he wanted to take off his clothes and dance around in celebration of fire but I said that he needed to be more mindful of boundries and I'd already been struck with hysterical blindness when I saw him dancing with his clothes on just a few days ago.

So anyway...for this project, I had to weld a lot, which means I had to grind a lot, which means I was taking a lot of showers because I got pretty gross. Not only did the dust get everywhere, but I was sweating like people you read about in books.

I was sweating so much because I was doing most of this work in my geodesic dome. I built the dome to shelter a small lap pool. Then I realized a pool is just a big bucket of water into which you throw money. Like a boat, which is a hole in the water into which you throw money. But I got rid of the pool and started taking down the dome when I decided to build my metal-working shop next year when we completely overhaul the current shop. So while the dome doesn't have a floor anymore, it still has a roof that is great for keeping the rain off you. It's also great at trapping the heat. And it was really, really hot. I'm pretty sure under my welding helmet my face was as pink and sweaty as a canned ham.

And now I'm disgusted and hungry.

I'll let Burnie cool over night and pop the lid open tomorrow to see if there's any charcoal in there. I'll update soon.

[TwistedCustoms]

Can't wait to see what's inside!

[Buzzkill]

I hope it was a big success, but even if it isn't I still want to hear about it.  You always succeed in bringing a smile to my face when I read your posts regardless of the topic.  Thanks for that.

[Ohio]

So, there was charcoal. A lot of charcoal. And the barrel was still warm when I opened it yesterday afternoon. Guess the insulation worked.

I have loaded Burnie up for a second burn tomorrow and try to get some time to try the charcoal in the forge sometime this week. Maybe. I have to harvest the lavender for distilling, so I will be very busy but very calm.

[Daswulf]

Awesome. Nice looking charcoal. Now I'm wanting to make one like that. The "burn barrel with blower then snuffing out" I use is no where efficient like that.

[JME1149]

Nice story. I'm curious to know how many hours of burn time produce how much charcoal that gets you how much forge time.

[Ohio]

Hey, Daswulf, the build is pretty easy, however...you can't really seal anything. I used a clay mix that actually worked pretty well (surprisingly) but not completely. I'm going to try a 3m fireblock caulk product rated to 1348F and a clay with rockwool mix, giving the clay some fiber to hang onto. See? Fiber is good for you.

Primarily, I'd like to seal the lid to the barrel and where the stack protrudes from the lid. I don't want to weld on any more bits because the idea is that the rocket stove is the permanent part while the 55-gallon drums are consumables. I estimate I can get 5 or 6 burns before needing to replace the barrel. My neighbor estimates over 20, but we agree the barrel will have to be replaced at some point. This suggests perhaps using a different barrel or heavier steel fabricated barrel and lid, but weight is an issue. Rocket J. Stove weighs about 80lbs and is clumsy to move.

The rockwool is also a little problematic in that it can't be handled easily, which is why it's wrapped in fencing. I think diamond mesh/lathe would work just as well and may let you avoid using flashing. My neighbor sort of muttered about building a box, put Burnie in it, then fill it with vermiculite, and that would solve the issue of the insulation. But that would be for a permanent install, and right now everything is moveable and I can take it apart pretty quickly if I need to. I'm thinking I may put Burnie on a small trailer I can haul out on my UTV when I need to. Either way, the insulation is a key part of the process---I think that there's so much surface area with the barrel that the heat is dissipated too quickly to sustain complete pyrolysis.

Wow, that was pretty science-y this early in the morning. And I haven't even had any coffee.

JME1149, 3 hour burn time, I actually timed it. I didn't weigh the feedstock or the fuel, which I probably should. In terms of estimated volume, I used about 20lbs of scrap for fuel (1 5-gallon bucket and an armful of long hardwood rips). I don't know how much feedstock went in the barrel. Afterward, I filled four 5-gallon buckets I just transferred to a new 67-gallon recycle bin I bought for this purpose. I usually spend about 3-4 hours at the forge and use 2.5-3 gallons of charcoal in the JAGOD (Just a Grill of Dirt) at that time, but I'm still working out my fire management and I think I'm being too stingy with the amount of fuel I use.

The process is easy enough that you could fill Burnie the night before and then fire it up just as you're starting to forge or do something else nearby that doesn't involve juggling gasoline or other flammables. Once the pyrolization gases start cycling through, you're not doing much to help it along. We did feed fuel toward the end of the cycle to keep positive pressure inside the barrel. I think the pyro cycle was over an hour long, I think 1:15. I was timing it but I didn't write it down. The pyrolization lasted longer than I thought it would, for sure.

We also had small fires on the outside of the barrel from leaks, which is why I'm looking for an easy and safe way to seal the barrel, but you could track when the pyro cycle is over because those flames die back the closer to the end you get.

The big challenge is the size of the feedstock. I have to figure what is the largest size Burnie can pyrolize and what's the easiest way to get the feedstock down to a smaller size efficiently. I'd also like to try feedstock with different moisture content (greenwood as opposed to dry---my guess is that it would work, but take a lot longer) and what happens if I use other material, such as blackberry cane, as feedstock or fuel. Laugh at the blackberry cane, but it is related to bamboo and grows very thick and deadly canes. The canes have lots of thorns matched by a very bad attitude. These plants can grow into this massive thickets that could kill you and drag your body off. I'm pretty sure that's happened.

[Irondragon Forge ClayWorks]

Good job on Burnie... and documenting how well it's working. If I didn't use coal I would definitely build your version. I think your neighbor is pretty close to the estimate on the barrel. Before all the regs, we used 55gal drums as trash burn barrels and got about a year out of one.

"Roast me! Hang me! Do whatever you please," said Brer Rabbit. "Only please, Brer Fox, please don't throw me into the briar patch.".

[Steve Shimanek]

Ohio, you have a great sense of humor and writing style; if you write a book, sign me up for a copy

[Ohio]

Irondragon, are you challenging my ability to burn a steel barrel? Because I'll totally prove you wrong. And nice quote, dude.

Burnie is set up for tomorrow AM. This load is primarily big leaf maple and alder, all dried. I'm letting the clay and caulk on the lid and other openings dry tonight. I'll report back with the results.

And thanks y'all for saying nice things about my writing. I do have books published, but they have no explosions and only a little fire in them, though I do have a new work soft launching later this year. Mostly I just stream my consciousness all over an IFI post and usually I only go back to take out the swear words, of which there are usually many.

[JHCC]

Japanese smiths traditionally use softwood charcoal. With that in mind, I’ve been thinking that if I ever make a retort, I’ll probably be stocking it with lumber offcuts from construction sites. 

[Ohio]

JHCC, I've read that about use of softwood charcoal in Japan as well. Probably because the fire burns hotter.

I may have to do a softwood batch. I know cedar burns hot and fast, but there are a lot of pitch pops, which would lead to a lot of fire fleas. I usually start woodstove or forge fires with cedar scrap because it starts so quickly and I have a lot of it.

 

[JHCC]

Pyrolysis should cook out the pitch, whose gasses would then add to the re-burn. 

[Zrognak]

that looks like it works really good, much better then the one I made, I did not insulate mine probably one of the reasons why i had to go for so long, but I see you got a nice load of charcoal there how did it turn out, is it hard and glassy when you break it or soft and fragile?

[Ohio]

JHCC, that's true. Maybe the next batch will be softwoods---I can put that charcoal in a different container and compare how it works with the hardwood charcoal. Softwood is easy to find out here and I do have a lot of cedar scrap. Plus, everyone is giving away rounds from the trees they're taking down and there's usually a lot of hemlock and fir.

Zrognak, the first batch of charcoal was both hard and glassy and soft and fragile. I had mixed soft and hardwood and kept most of the pieces fairly small. The second batch was all hardwood and the pieces are glassy with almost no dust. I had also put in some big pieces to see how big was too big (and now I know), and I definitely have some that didn't pyrolize completely. The half-cooked pieces are in a different stack for going back in Burnie. Or the firepit.

Design-wise, I don't like the lack of seal around the lid and my last homemade clay and rockwool mix didn't work as well as I had hoped, so I'm chasing down some gasket material. Also, the rockwool works, but the insulation not covered by flashing gets very messy and is already starting to fall apart, so I may change to a different material. And emptying the container could be better. Now I just flip the entire barrel over onto a tarp to get out the charcoal, but I wonder if a trunnion would be a better method.

And I'd like to do something with the heat coming out of the rocket stove. I did cut in holes in the removeable stack as an afterburner and wow, did that work. That was a clean burn. But I kept looking at all the heat being wasted and wondered if I could do something with that as well. Pre-heat steel? Melt aluminum? Boil water and make myself some coffee?

But those are all refinements and not necessary, really. Burnie does what I need it to do. If I decide to make changes, they'll probably be when I re-do the whole thing and have Burnie on a trailer and stuff.

[Zrognak]

Cool and thank you for the information it should come in handy when I make my 2nd retort.

[Zrognak]

I had an idea a few years a that might be stupid reason I posting a poorly drawn drawing here, I have never tried this nor im I sure if it would be a good idea or not, but here it is, I had a hard time getting a good seal so I thought what if we use the ground as a seal and for insulation, so I thought what if we make the lid on the bottom instead, and weld a casing around the insulation, so you would put the retort on its side fill it up then put the lid on and lift it upright(i know you got to be strong to lift it up but can be done with all kinds of things) and then burry it slightly with sand or clay. This might be a stupid idea with all of its own problem, some might be able to tell without even trying that it is a bad idea but since I have not tried it myself I don't know.

Sorry not wanting to hijack this thread but it came to my mind cause of the sealing issues discussed.

[Frosty]

Not bad Zeognak though making a rocket stove isn't necessary or beneficial. You want to make charcoal NOT heat. Right? A drum with a clamp on lid, a little stove rope to seal the lid and some plumbing pipe and a couple elbows makes a good retort. Fill the drum with reasonably common sized wood and lay the drum on it's side in a long hole a LITTLE larger. The bung hole in the lid goes on the bottom, the plumbing aims back down under the drum. Cover the drum with a sheet of something non flammable. Fill under the drum with scraps, branches, etc and light it.

Close the opening to control how much air reaches the fire under the drum. When it starts working the pipe will provide the fire and you can stop putting brush in the fire. 

When it stops burning cover the draft and rake some ash against the open end of the pipe and let it cool.

It's so much easier than making a rocket stove and has at least as good a yield.

Frosty The Lucky.

[Zrognak]

As always, thank you Frosty for sharing

[SLAG]

Why not vent the gas to the plenum where the fuel is burning. That gas is volatile and highly flammable.

The way I interpret your drawing the volatile gasses are venting to the environment. Which would be a waste of the gas and a source of air pollution. That gas can burn there  and raise the temperature, thus saving fuel.

Destructive distillation  or pyrolysis of the wood cooks off lower molecular hydrocarbon gasses and leaves mostly carbon behind. (a.k.a.  charcoal).

Just a thought or have I misinterpreted the drawing.

Regards,  and  happy cooking.

SLAG.

[Zrognak]

Yea that was the plan, the vent hole on to is just so it wont explode, the drawing is poorly made sorry, I got a vent like a hook shape so the dust does not clock it up or smaller pieces of stuff though is not clear down at the bottom where the fire is so it pushes in the gasses that are made from the wood so they are burned when the top vent is closed if that makes sense.

Sorry been drinking since its my last day home, and the school im going to dont allow beer im just having some of my favorites, the drawing is poorly made if i spent another 10 or 20 minutes it would make more sense. meant the drawing to show that the gases would be pushed into the heat source so they would burn or retort is that the right work, anyway thx for the info.

[Steamboat]

Here's an article about some historic approaches to making charcoal on a large scale. I suppose that one might lump them together and call them the JAPOD method (JUST A PILE OF DIRT...or sod, or clay, or stones, etc.). I imagine that the life of the average professional charcoal burner was dirty, difficult, unpleasant, dangerous, low-paying, and probably boring at the same time, but they did convert vast stretches of woodland into charcoal for a myriad of purposes over the centuries, helping to fuel (literally) social and economic change.

http://www.vtarchaeology.org/wp-content/uploads/200_years_ch5_optimized.pdf

Al (Steamboat)

[Zrognak]

13 minutes ago, Steamboat said:

Here's an article.

That is really cool man, thank you for sharing

[Steamboat]

I'm glad you found it interesting, Zrognak. Circular features can sometimes still be discerned in the landscape that resulted from the use of the round mounds where wood was burned/heated to convert it to charcoal. Round, lime-burning "ricks" could also leave circular patterns.

Airborne LiDAR data can be processed to filter out vegetation and create a "bare-earth" image of the ground that can make some of these often-subtle circular features stand out clearly.

Zrognak, this is a bit off-topic, but you might be interested in this article about lime burning in Sweden: https://uu.diva-portal.org/smash/get/diva2:704117/FULLTEXT01.pdf 

Al (Steamboat)

[Frosty]

I was road trippin in Nevada some decades ago, my usual vacation was a month long escape to warmer country and new sights. Anyway I was on a secondary highway maybe, on the Sierra side of the state I believe and saw several, 3-4 giant bee hives on a ridge above the highway. I found an access road and checked them out. They were about 60' ID. as paced off and I guesstimated about 50-60' tall. Almost conical but more like a tall bee hive. The coffee shop regulars at the close by town told me they were charcoal kilns from the silver mining days.

I'm sure I have pictures somewhere I took pics everywhere I went. Unfortunately I have zero idea where to even look in the basement. 

Those are both excellent articles. Thanks for the link Al.

Frosty The Lucky.