Greg Martin wrote:And if you don't want to spend hundreds of dollars on a metal cone kiln you can just dig a pit in the earth the shape of a cone kiln and do the same thing in this fire pit. I've been doing it for years. It works great and doesn't waste any of the wood....it all converts to Biochar. Here's one example. Not perfect, but you get the idea. https://www.youtube.com/watch?v=h9J7J4fQHpo Just start with small diameter wood. Then move up to any larger diameter wood (not too large or you should split it because it won't have time to fully char unless you do this in a fairly large pit). Finally finish with small diameter wood, dried grasses, etc. You layer in more wood as the wood below it converts to charcoal. When heated, wood generates flammable gases and charcoal. The flammable gases burn and consume the oxygen so that it can't get below these burning gases to the charcoal below it. You keep layering new wood over the charcoal as the flammable gases stop being produced to generate more gases (and more charcoal). Eventually the pit will be filled with your Biochar and you can then quench it with water from a hose. The resulting steam will help react with tars in the charcoal to clean it's pore structure up so that you'll have better Biochar. After the hose treatment has been done for a bit you can add buckets of water to speed up the quenching process. Fill those buckets while you're doing the burn. After that I turn it a bit with a shovel to make sure it's fully wet out. If there's still any dry spots I keep going at them with the hose until it's all wet. Dry spots could cause the pile to reignite (never had that happen, but I'm pretty thorough). Then you can let it finish cooling and use it in your compost, in sheet mulches, anywhere where organic matter is breaking down. That will help build the microbial and nutrient levels in the Biochar. I promise....super easy, very satisfying and no expenses, just a great way to clear up your brush while building fertility that will last hundreds to thousands of years.
Well it takes some kind of energy one way or the other to cook rice and veggies. I make char, and make supper. To me there is no waste... ...but maybe I'm just a pyro at heart! I've never tried to get into the cone thing. It might work to cook on that, without wasting wood.
I saw pictures and they use wood in the outer chamber probably to increase the temperature, isn't that a waste of firewood? I want to use debris only!
Wherever you do the burn should be clear of dry material, just to be safe. One thing to consider is to make sure that your drums are completely cold when you open and dump them out. I've had some that were still warm but the internal chars were still hot---they burst into flames, causing quite a fright. I wasn't dousing with water at that point in my process; now I do.
we can put it on the terrace
I may try this method in the spring.
you can make the pit any size you'd like. Rough rule of thumb is half as deep as it is wide. Save up about twice the pit volume in woody materials and then go for it (the volume of the wood shrinks by about 50% when charred).
Roberto pokachinni wrote:
Are people able to use greener (fresh cut, not dried and cured) material in these cone burns? It seem like it would be alright, though not ideal, as damper material would create a less hot fire, but at least in an open pit there is not much chance of a steam build up in the cone. If not green wood, can a person use damp wood (from standing dead material, like my pine) that has been left outdoors?
you REALLY want to use dry
Thanks guys. That's what I suspected.
I have tried it and the results were never good.
Yes. I only do dry wood in my retort. I always thought that this was best and have had good results. I was just curious if the open pit might be different. Thanks for your input John.
I have also heard this from other sources.
Greg Martin wrote:. If you really want to use wet stuff check out "hydrochar". That process can use fresh cut, wet stuff.
Angelika Maier wrote:The second problem is that the material has to be very dry, which in some areas would pose problems either of neighbours complaining about unsightly heaps or firehazards or it simply is too moist.