I am attempting to make some Terra Preta by adding ground charcoal to compost for the garden. I've been putting some chunks into a can and grinding it with a worchestershire sauce bottle. It's not stupendously effective. Beating on it with a sledge on concrete is sloppy and wasteful.

So, does anyone have any clever, easy, simple, non-messy (mostly) ideas on how to grind up about a cup of charcoal at a time? I have a mortar but no pestle, and haven't been able to find a suitable rock.

Thank you for any ideas.

Sue

Put some in a ziploc and drive over it?

It seems that the plastic would puncture before the charcoal broke up, but I could try it. Maybe between two boards?

It's supposed to pour tomorrow, a big storm coming in. I guess it wouldn't be the time to try it...

Sue

Got a dowel? A pestle need not be made of stone, a dowel will work (spare handle)

Or you could imitate fowl and make a gastric mill swallow some gastroliths and shake shake shake shake (charcoal + marbles/gravel + drum = ball mill )

meat grinder..a old hand cranked one.even if it's one that you use charcoal could be washed out with no problem.

Will it blend?
Even a cheap blender from the salvation army store will do to grind charcoal.

Other that that I would say to put it in a gunny sack with a couple of rocks and smash the heck out of it.

A couple of Red bricks,or Broken chunks of concrete,or a small hammer slowly pulverizing it,should do the trick,or a couple of Pavers from the garden also!Make sure you've got some eye protection going on.Soak em' in the rain,when they dry,they'll be alot softer.Good Luck!

I think the dust would make its way into the bearings and destroy them pretty quick.

I started working with agrichar/biochar early last year. I've made about three 55 gal. drums. Excellent results in the garden but watch the soil pH.

I don't worry about grinding it too fine. I fill a 5-gallon pail half full and work it with a garden spade. Once it's down to marble size, that's enough. Time and rototilling will handle the rest.

Doing this creates a lot of very fine material mixed with the bigger stuff. There's no reason you couldn't sift it through a coarse screen -- secure it over the top of the pail, invert, and shake baby shake.

There's no clean way to handle finely ground carbon. Be prepared to resemble a chimney sweep. Oi, guv'nor!

Sue..what sort of charcoal are you using?..i'm let to believe that the stuff you use in a BBQ is not real charcoal but has a lot of nasty stuff added.the real thing seems to be lighter and "crunchy"

The little briquets are usually compressed coal dust, and often have accelerants in them to make them start faster.

Real charcoal does not come in neat little briquets.

Mortar and pestle is the age old solution to grinding things.

In case anyone is interested, you can make charcoal out of any wood you have lying around in a wood gasification stove made of two tin cans.

Do a google search on "plumping mill".

-Blast

I've made black powder with charcoal. To turn it into dust, I put it inside a suede leather bag, cinched the bag shut tight, and pounded it with a brick against a concrete curb. The suede kept the charcoal contained, and was tough enough not to be punctured in the process. When I was done, I had about 4 cups of charcoal powder that was as fine as sand or better. It took me maybe 10 minutes all told. I wasn't much concerned with production rate, so probably could've gone quicker.

An idea that popped in my head just now is to use a cheese grater! it is slow but it will get it fine enough and it is probably the easiest to clean! (have the hubby do it...LOL, seems more natural!!!) perverted humor.. I love it!!

This is regular wood charcoal, not briquets. The morning after I have a fire in the stove, I pick out the leftover chunks.

Several really good ideas here. I KNEW you guys would come up with some!

I'll try all of them and see how they work!

Thanks!

Sue

Doug, I was using small chunks, but there's a new book out on BioChar where they talk about the charcoal in microns.

Which way does the pH go, up? Up, I could use, as my pH is about 5.8.

How do you make it in the 55-gal barrel? I read something about filling the barrel with wood and getting it started, then tipping it over to shut out air intake. Tips?

Sue

plastic bottle with little rocks, marbles, or ball-bearings? shake and then pour out? slipjoint pliers stuck in a bag or covered with something. (thats how i crack hickory nuts, the bag/cover is to keep the flying bits from going all over the place)

Sue, my char goes in the garden, and the big John Deere rototiller will smash it into powder over time. But in a raised bed or pot-based garden, the best results come from finely-ground char.

Like ashes, char will tend to raise the soil's pH. Sounds like you can add a lot without worrying. I have to watch it, my clay-based soil leans toward alkaline/basic.

My charcoal-making is incredibly primitive -- a Bic and a long-handled spade. When I have a fire in my big firepit or my Landwave mobile burner, I just keep tapping away at the partially burned material and packing down the charcoal to keep the air off it. I have done this for years for natural-wood barbecuing. When the pit is full, I spray it down a little with water (don't saturate) or add a little snow on top, and then put an airtight cover on it. The steam plus cover kills combustion. Done!

I'm planning a better system. I want to make use of the heat produced (I'm in a winter climate) and I want to cut down the amount of smoke I eat (*koff*).

I like this simple setup using two different size metal pails/barrels:
http://www.holon.se/folke/carbon/simplechar/simplechar.shtml#two barells

I'm really intrigued by this burner/charcoal maker:
http://www.treehugger.com/files/2010/03/biochar-breaks-through-in-haiti.php

The other option is to use a "cartridge" system with my existing wood stove. Short pieces of stovepipe with metal caps should do it.

Long post, sorry 'bout that.
Doug

P.S., if you char grass instead of wood, you will get instant powder. No need to grind it.

lite version, color photos
Fuel from the Fields A Guide to Converting Agricultural Waste into Charcoal Briquettes

more detailed, schematics
Sugarcane+Charcoal+Manual+Draft+October+2004.doc (alt link)

and here is Amy Smith demonstrating the method
YouTube - How to make charcoal briquettes from agricultural waste


update: ooOOOoouuh fibonacci spiral
YouTube - LuciaStove in Pyrolytic Gasification Mode for Biochar Production
http://worldstove.com/products/luciastove-for-developing-nations/

Thanks for the The barrel method in the first two links is incredibly crude -- not much more than what I'm doing now. It may work with grasses, but I suspect you'd get a lot of ash if you used wood. The main problem is that you create a lot of noxious smoke and gases (that "closed-in fire" smell), and you waste the potential heat source.

But I'm blown away by the LuciaStove. It burns clean. It lets you use the gasification products for heating. This is exactly what I want to build, except on a larger scale (and possibly with a series of removable fuel "cartridges" for continuous operation).

Here's a good rundown on the LuciaStove, its components and principles (w/subtitles):
http://www.youtube.com/watch?v=QsH_Gh-n2Mg