I am always happy whenever Redhawk is posting on a thread I like because I know I'm going to learn a lot.
I am using 55 gallon drums, which I can get for free off Craig's list in my home town . TLUD because it seems I can make lots of biochar more quickly than with retort. Many retorts have tiny inner chambers, and I also found it very difficult to find the inner chamber. Other systems are inefficient. TLUD is efficient, partly beause the fire is funneled into going straight up quickly. I found this video to be extremely helpful:
I did everything in it, except for cutting the hole on the top of the stove. I think you can draw a circle around your chimney on the top of the barrel and cut into it with your angle grinder. My chimney was a bit different, but those were the parts I could get.
You have to see when the fire settles down and then douse it with water. It makes fantastic, light, metallic sounding biochar. I simply grind it with a simple 2 x 6, with another piece attached to the bottom so it's wider there. I wear gloves.
Then I have inoculated it with urine, sea water, compost, rotten fruit, or anything else nutritious that was around and that I could use. For a month. Then I put it in the garden.
I am excited. Healthy soil and declining carbon in the atmosphere = Less climate change and better food.
Let's use the wisdom of previous indigenous peoples' civilizations as a tribute to them and their ingenuity.