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Any new small charcoal retorts out there?

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On 10/04/2019 at 18:50, axehaircut said:

316 will work but wouldn’t take a whole lot more particularly if it’s going to be near direct flames

It's now done a couple of burns and seems to survive. Not having an easy life though. The expansion bar is a tube so popped the thermometer inside of it mid-burn. It was reading 550C mid hight in the retort but the bar is low down in the firebox with all the gases and reached 820C 😳

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I reckon I need at the absolute minimum a capacity equivalent to a 5' ring kiln to make it worthwhile. Ideally two of them working in rotation. I'm tempted to go the small retort route but I wonder whether the volume would make it feasible. 

My trouble is doing the whole thing on my own and stacking and unloading a ring kiln is going to require some ingenuity. To say nothing about setting the thing up in the woods in the first place. 

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1 hour ago, Gimlet said:

I reckon I need at the absolute minimum a capacity equivalent to a 5' ring kiln to make it worthwhile. Ideally two of them working in rotation. I'm tempted to go the small retort route but I wonder whether the volume would make it feasible. 

My trouble is doing the whole thing on my own and stacking and unloading a ring kiln is going to require some ingenuity. To say nothing about setting the thing up in the woods in the first place. 

There are few upsides to the retort rout. 

 

Cleaner burn

Fast turnaround. Mine you can use continuously so no waiting 36 hours for it to cool before unloading

Easier handling of the charcoal and loading

Better conversion rates (so I am told, never used a ring kiln myself)

 

On the throughput. From some quick maths, a 5' ring kiln holds 1.6 m3 but due to needing 36 hours to cool can only realistically be fired every other day. Mine can do a cube a day every day so actually, coverts more (presuming similar conversion rates) even though it's small. I should add it's still in development so not really trying to flog it yet 😀

Edited by Woodworks
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30 minutes ago, Gimlet said:

Reckon you'll be ready to flog it before the autumn? 

Yes. I could now but as it's only plans but would be nice to have it just a bit slicker first. I am still on my heavily modified MK1 and it looks like it haha. I want to try out a few more mods and these things seem to take an age. Only asking £20 for the plans. You would get working drawing and admission to a closed facebook group to help with construction and use. 

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Accepting you're still refining it, any idea, very roughly, of likely production costs when building from plans?

 

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1 hour ago, Gimlet said:

Accepting you're still refining it, any idea, very roughly, of likely production costs when building from plans?

 

£1000 region. I had mine cut and folded by a local laser cutting place and I riveted it together. The insulation materials don't come cheap and then you need a few bits of stainless here and there. 1k is working on you doing some of the work. It's all pretty basic stuff like drilling and cutting. I intend to get costs far more accurately worked out on MK2 so don't hold me strictly to the £1000 as it's been a learning curve

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No worries. Thanks for that. 

Another thought has occurred to me since - and apologies if this has maybe been covered elsewhere in the thread but I'm in and out so haven't time to look - and that is, what length of wood can the retort take. 

All my wood is in cords, average probably between four and five foot long, most of it 6" think or less. If I bought a 5' ring kiln (or even a 6'), to load it tightly I'd have to cut each cord into at least three bits, more for the centre. That's quite a lot of extra work. Leaving the cords longer and feeding them in lengthways could be a significant saving in time and labour.

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12 minutes ago, Gimlet said:

what length of wood can the retort take. 

All my wood is in cords, average probably between four and five foot long, most of it 6" think or less. If I bought a 5' ring kiln (or even a 6'), to load it tightly I'd have to cut each cord into at least three bits, more for the centre. That's quite a lot of extra work. Leaving the cords longer and feeding them in lengthways could be a significant saving in time and labour.

4

2' 9'' max. If you load it with full-length pieces I suspect it will be slower to convert. Turnaround is fastest with the woodcut fairly short and not too chunky. I did a batch of 15" heavy logs the other day and it took around 30% longer. It's why I mentioned a branch logger at the start as these size pieces convert very swiftly I presume due to the surface area exposed to the heat.

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