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The Claude Moore Colonial Farm project


Christopher Price

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I will keep that in mind, but I would very much like to find a reliable method of backyard coaling. I'm not under any impression that the yield by weight should be anything other than what you suggest, Yan, I just need a method I can do reliably at this scale. I suppose small "campfires" and a water hose might be one way to skin the cat. I can run the retort with the lid off to dry the wood before coaling it down, I suppose, if the moisture's an insurmountable problem.

 

I guess the most vexing question I have is, how hot does the chamber need to be to char wood effectively? Is there a way i can increase that temp using something built off the current model, or do I need to start again from scratch with a whole new rig? Or do I just take a regular barrel, stack the wood in there, pour a little gas on top and light it, let it burn halfway down, and throw the lid on and let the rest smolder?

Edited by Christopher Price

The Tidewater Forge

Christopher Price, Bladesmith

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Have you read this thread? http://www.bladesmithsforum.com/index.php?showtopic=17918&page=1

I find it hard to imagine that you haven't but better safe than sorry. Also good to note for the others following along on this thread to go read it if they haven't yet.

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Chris, I think the retort you have made will work fine, it will just take some time to fine tune it. From the picture it looks like the pieces of wood are too close together. Maybe try cutting them to shorter lengths so that they can be stacked in ways that leave plenty of gaps for the heat to flow through. Also try sort the pieces of wood from largest to smallest from your heat source. Many times using a retort I thought that the wood was finished charring because it flamed up and off gassed then stopped, but if I kept the fire stoked for a little while longer it would kick off in earnest,( some kind of equilibrium stage?) The hardest part about that was it would want to runaway at full bore and cook it to a crisp with some wood species. So slow and steady wins the race.

Edited by brandon p
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Have you read this thread? http://www.bladesmithsforum.com/index.php?showtopic=17918&page=1

I find it hard to imagine that you haven't but better safe than sorry. Also good to note for the others following along on this thread to go read it if they haven't yet.

 

I read it when he posted it, missed it in my recent round of research, though I recall the properties of charcoal Dan mentions as important. Going through it again with a keen eye.

 

As for my half-baked batch, I'm going to run it again after jostling around the load a little, and see if it was just the moisture getting in my way, or the kiln itself. The unlimited pine source I have is all going to be soggy, so I gotta figure out how to deal with that, without needing 8 hours at a time tending the barrel. That's my whole weekend right there, and I'm going to need a lot of this stuff for the 6 smelts I have planned. The upside is, I have 6 months to get ready. The downside, is that I can't let the wood sit out in the winter weather for 6 months and expect it to get any more dry.

The Tidewater Forge

Christopher Price, Bladesmith

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Ok, after re-reading Dan's thread (with more recent updates) I'm convinced that I need one of those IR thermometers, so I can get a better sense of temperature of my operation. I also figure I need to cut my wood down to small lengths, and try and dry them a bit. I can build a metal shelf over my forge, and stack up a pile while I work, and then use that batch in the barrel so it's not so wet. Maybe that will be the difference... maybe adding a small squirrel cage blower pointed at the firebox will improve the heat, too... start with the easy tweaks before I give up and start over. Wish I had the land to do what Dan, Lee, and Wally pull off.

The Tidewater Forge

Christopher Price, Bladesmith

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I've used a retort before for making charcoal, Mine was a 55gal drum on its side with the lid clamped on, and 1.5" black iron pipe attached to the plug hole on the lid, with elbows and caps so that the pipe terminated on the underside of the barrel, and 1/8th" holes drilled at at least every 4 inched or so for the wood gas to in turn feed the fire. The barrel was placed on cinder blocks so that a fire could be built under it, and the whole contraption was then encased in cinder block up about 4 ft with a piece of tin for a roof. I was able to feed logsinto th3 fire until the wood was dry enough for the gasses to fire the whole thing. Wetter the wood in the kiln, the more firewood I had to use to get it up to heat, but it was manageable. And, looking in, when the flames coming from the tube had worked down to being little Bic lighter sized candle flames, I knew the wood had been nearly fully converted so I no longer had to feed it.

 

Left it alone, came out the next morning and collected my charcoal. Main thing is just to make sure no oxygen is getting inside the retort chamber

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I am sorry for butting in. Just a question, pine was used for charcoal making yes? Was it fresh as in freshly cut, or just wet from sitting outside in wet conditions?

Pine can successfully be used for making cooking fires on top of snow. Freshly cut healthy pine gets chopped into pieces and made into a table. The fire is built on top by fresh birch usually if you're cooking. The reason being. Fresh pine does not burn. It needs to dry out before it burns.

 

Fresh birch does burn, and coal. However, if you take a dry piece of birch, put it in a bucket of water so that it weighs as much as it did when it was fresh. It will act more like the fresh pine.

 

If I remember right the words of the old men, wood that did not go into sawmills (and later papermills) was used for coaling. Being cut in the spring/winter, dried out and then coaled during the later parts of the year.

 

(I am not sure if this is in any way helpful. I am not from a coalmaking background and I hope I am not writing anything inaccurate)

 

//DQ

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I will keep that in mind, but I would very much like to find a reliable method of backyard coaling. I'm not under any impression that the yield by weight should be anything other than what you suggest, Yan, I just need a method I can do reliably at this scale. I suppose small "campfires" and a water hose might be one way to skin the cat. I can run the retort with the lid off to dry the wood before coaling it down, I suppose, if the moisture's an insurmountable problem.

 

I guess the most vexing question I have is, how hot does the chamber need to be to char wood effectively? Is there a way i can increase that temp using something built off the current model, or do I need to start again from scratch with a whole new rig? Or do I just take a regular barrel, stack the wood in there, pour a little gas on top and light it, let it burn halfway down, and throw the lid on and let the rest smolder?

Hi Chris-

I don't think that last question was answered-- I like to see over 525 F on the surface of my container, regardless of retort or smolder method.. The IR pyrometer is super handy for coaling, and they're cheap now. I notice a big pause in my temperature climb around the boiling point, and then another hang in the 350 range, another around 425, and then it'll shoot through 500 and 600 pretty quick. On the smaller retorts, I've also noticed the pause in burning gases brandon mentioned.

 

In general, I think you just didn't go long enough.

 

I also think you might be losing most of your heat through the chimney- it's shooting out before it has time to heat anything. A damper or some baffles in the pipe to create turbulence might help your heat transfer to the chamber.

 

A friend who does something similar has the chimney going through the center like you do, butthe whole thing is sitting above a firebox of another half barrel. That way he's heating the bottom of the barrel, whereas you're trying to heat the whole thing with the chimney.

 

Typically, I think most folks would be insulating the outside of the barrell, rather than using up that valuable interior space you could be filling with wood.

 

And lastly, on all three of the retort designs I've made, I found the most efficient thing to do is to cook a gentle fire underneath for a few hours to start drying things, then come back the next day (or later) and kick up the heat to finish the deal.

Edited by Lee Sauder
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Those all sound like really good ideas, Lee, thank you. It's going to be a soggy weekend, but I'll get back to it soon and report. I dearly appreciate all the helpful ideas. This is the one part of the process that seems to hold a lot of people back because of the cost of buying charcoal (and the questions of quality that have come up recently), and I've never done at any appreciable scale. I do a lot of charcloth, and I've done the little sticks in a can thing, but this is a wholly different animal. At least, all the other elements of smelting I've had experience with, so hopefully the rest of the project won't feel so frustrating.

The Tidewater Forge

Christopher Price, Bladesmith

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I did some reading on coaling, saw on several places mentioned that the moisture should be below 35%. If you suspect that moisture is the problem, it can be rather easily checked with an accurate scale and a kitchen oven.

 

I can't find the blueprints and description now, lost the website.. But a more recent addition to the kolmila was a directed chimney of sorts, which directed the heat into the next batch of wood about to be coaled. Drying it further. Is it possible for you to do something similar?

 

//DQ

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My initial plan is to cut the wood into smaller pieces, and do some drying before attempting coaling - lee's under-barrel fire idea is something I was toying with right after I popped the lid to take the last pictures. I have a pile of old wood that's not good for the fireplace, scraps and trimmings, and a couple ancient bags of kingsford that would make good burn stock for pre-drying.

 

If I can't get the existing barrel to work, I'll probably just pull the chimney bit, and do the controlled top-down burn-and-douse, and adjust my plans from there.

 

And the moisture meter, and an IR thermometer are on my Christmas list.

Edited by Christopher Price

The Tidewater Forge

Christopher Price, Bladesmith

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  • 4 months later...

After an entirely derailing winter, I got back out to the rocket kiln.

 

I am happy to report, that using dry wood in the kiln, and with less external fuel than a simple campfire would consume, I got an entire load coaled down in about 2 hours of operation. Once it kicked into high gear it was epic to witness, and I'm a little surprised the neighbors didn't call this one in. The burning volatile gasses were bright yellow and roaring hard, all on natural draft and the pressure in the coaling chamber pushing out hard. Quality of the charcoal appears very good, though I haven't burned any - I will try some shortly, just to see how well it burns compared to store-bought.

 

Now that I know that it works, I re-stacked my wood piles, so they'll dry faster outdoors, and can easily rotate stock into the shop for drying in the rafters for a forge session or two.

 

With the first demo only 6 weeks away, I need to make use of every weekend, and work my way through the pile of wood I've got. I also decided to go with a smaller stack than a Catalan, at least for the first demo - time and money are against me putting that rig together, and as much as I want to do it that way at some point, I need to do it right, not fast.

The Tidewater Forge

Christopher Price, Bladesmith

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  • 1 month later...

After watching Mark, Jesus, John, and Dennis run a half-size Catalan last weekend, I'm more than happy with my choice to avoid it. Far too much work for one person, and my assistant I'd been planning on still may or may not show up.

 

That said, I've been making charcoal quite effectively with the rocket stove retort, and found a pottery place in Philly that will ship me EPK clay for about the same cost as the material itself, best I can find around here. From points south they wanted almost a 3:1 ratio to ship vs. product cost. That's ridiculous.

 

Tomorrow is set-up day, so while I wait for my clay to arrive (so I can build the base) I'll construct my plinth, chop charcoal, pour the fines into the base (I would like to end up with steely enough bloom for an ax... 40 or 50 points all around would be nice) and have a fire roasting ore, so I can get it crushed and ready by tomorrow evening - leaving me with the furnace base and plumbing pretty much the last things to worry about this next week.

The Tidewater Forge

Christopher Price, Bladesmith

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Unless, of course, it rains. 80% chance of half an inch Saturday afternoon. Now I need to go find a piece of sheet metal to cover the base with if I can get the bloom out before the storm hits, if we even run it. :wacko:

The Tidewater Forge

Christopher Price, Bladesmith

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