5 gal bucket retort for making charcoal

[elmoleaf]

This is small wood charcoal retort made from a metal stain bucket and a piece of tube from a swingset. 
I dont have a welder, so this is super simple. No big hole drill either ( hole in lid and bottom of bucket made by drilling bunch of small holes and chiseling thru to connect the dots.)

The tube came with that change in diameter. So once tube put thru bottom of bucket, a simple cross rod on bottom outside holds it snug to bucket bottom. At the bottom portion of tube inside the bucket, i drilled a bunch of holes to let wood gas out of the bucket and into the tube to burn off.

The lid simply drops down on top and gets covered with dirt for insulation and to help seal around the pipe. I also drizzle some sand around pipe inside the bucket to also seal that joint. The lid doesnt have a gasket so is somewhat leaky, but top of pipe still roars like a rocket after about 30 minutes, and is generally done after about 2.5 hours.
 

I have this set up on a small semi circle of bricks to make a small burn chamber under the bucket.

 

[pnut]

I've been making pretty high quality charcoal in a five gallon bucket with holes in the top. I just build a fire around it and when white smoke stops coming out of the holes I cover the holes with dirt and restoke the fire. I'm getting a pretty good return also. I haven't made a batch since about April though so I'll have to wait until I make another to post some pictures. 

 Your retort looks effective. I was trying for the simplest way to go. 

Pnut

[elmoleaf]

Yes...was trying also for simple design with materials on hand. Definitely wanted design that’d burn the off-gassing to avoid smoking out the neighbors.

I have some leftover wood stove gasket that I’ll add to the lid...hopefully by burning more of that smoke, it’ll give more heat towards cooking the wood and reduce need for external fuel...which has been about two five gal buckets of sticks and bigger chunks of dry blown down limbs from the woods.

Wood being cooked is old pine 3/4 boards, split and broken down to 2-3” chunks via hatchet.

[pnut]

Pine is what I prefer. It's easier to source hardwood pallets for me though. 

I don't have to worry about the neighbors so smoke isn't an issue or I'd definitely have to burn the off gassing by products. 

Do you plan on scaling up? I didn't really need to. I usually make three buckets at one time. If I had more time to devote to forging I'd probably have to up production. I try to stay one step ahead of my use by running two batches before I started using any. 

Pnut

[Frosty]

The times I've made a charcoal retort I directed the "smoke" from the retort back under the drum to burn and contribute to the process. After a while you can stop feeding the fire and when it goes out it's time to close the vent and stop the process to cool. Not having a bed of coals under the drum makes for less loss. (I think)

I've seen that type the type retort you built but don't have any experience with them so can't opine. I don't have close neighbors to worry about a little smoke. I also do light repairs and sharpen knives gratis for PR. Actually I like our neighbors, nice folks since the evil witch woman moved.

Frosty The Lucky.

[Paul TIKI]

This is a great idea.  I'm gonna have to try this soon.

 

[tjdaggett]

I had not thought of elevating the bucket like that and putting the fire under it. I've been nestling cans down in my fire circle and building a fire over and around them. I think your method would let me use a smaller fire and would lower the amount of hands-on attention it requires. I always intend to do yard work/shop work while I burn, and then I get stuck feeding the fire. 

Am I right in thinking that, in the absence of a good seal, a decent diameter pipe is important? I'm imagining that too small a pipe would encourage the smoke to find the weaknesses in the design and escape, rather than going up the pipe.

Is there any kind of heat-proof sealant or epoxy that would form a permanent seal between the pipe and the bucket? I'm not familiar with that stuff yet, just imagining. 

[elmoleaf]

The pipe diameter on mine is a bit small....was a tradeoff between reduced flue functionality and maximizing volume inside of can for charcoal....and it was only pipe I had available. The fire below the can also exhausts a bit thru the sides of the loose brick stack holding up the can.

Furnace cement is also cheap temp seal for the pipe penetration and is easy to break apart when done cooking.

[Frosty]

A 5 gal retort is almost silly small for that design. A center tube large enough to draw reduces the payload too much. Make it long enough and a lot of combustion is occurring outside the retort doing little but reducing smoke. AND you're burning 10 gal of sticks to pyrolize less than 5 gal of charcoal? 

It's a good design just not on this scale, I believe it really starts working well is around 15 gal payload. 

You do know these are a minor modification of a "Rocket Stove," yes? 

Frosty The Lucky.

 

[elmoleaf]

Yes Frosty all of the above noted. It is only using about 2 five gal buckets of wood limb/junk wood to fire for 3 hours max. If I do other things outside while tending, it’s not unreasonable effort vs return for my situation. For decent volume of charcoal to time/effort, a 55 gallon drum is certainly the way to go. I will upscale to new retort if I continue with charcoal.

[elmoleaf]

Here is a link to very short video of the retort in action.