Monday, April 7, 2014

The Original Proof of Concept Prototype Version of My TLUD

I drug my little TLUD out the other day, so I could make as much biochar at a time as possible (since most of the work is just standing there watching the TLUD, I might as well use both of them).  Since I'm also on a mission to get more people making biochar and experimenting with it, I thought it might be worthwhile to write a little bit about this little TLUD.

When I was first trying to figure out how to build a simple TLUD, I used a little 16 gallon barrel I had that had a rusted out bottom and wasn't really good for anything else besides building an experimental TLUD.  Standing next to a 55 gal. barrel, it looks pretty small.
It was rusted out enough that I first started out by using a ball peen hammer to hammer about 8 holes around the perimeter.  When I first tried to make bio-char with only the big holes around the outside, it smoked like a locomotive, and didn't really work as a bio-char making machine.  So, on my second try, I punched some more holes in the center with a punch, and it seemed like that gave me enough air flow to actually work like a TLUD is supposed to work.
I only had one lid for this barrel, so I used an old satellite dish that I had for my chimney lid (it was bigger than the barrel and had a nice domed shape to it, so that's what I used).  Using a grinder with a cutoff wheel, I cut eight slots in the center and bent them up so I could attach my chimney.  Just like the 55 gal. version, I wrote about before, I cut past the 8" mark to leave little slots at the base of the chimney to help feed the "afterburner" fire in the chimney.

For my chimney, I had part of an old chicken feeder that was missing the bottom part, it's about 8" in diameter, and might have been a little big for this barrel, but I used what I had.  With a chimney that's proportionally bigger in diameter and a little shorter, the flames will come out of the top of the chimney (which might be pretty cool to watch at night).

When this chimney was a chicken feeder, it had a rod running the length of it that went through this crosspiece, which I left to use as a handle to move it off and on the barrel with something like a pitchfork, a long stick, or something similar.

From this point on, the little TLUD is used in the same way as the big TLUD, and I thought I had some pictures of some dueling TLUDs during the burning process, but apparently the camera decided it would be overkill to show that many pictures. 

So, try to imagine that these two TLUDs are lit on fire, the chimneys are put on and the flames shoot out of the top of the chimney of the little one, while the big one is a little more bashful about showing any flames and usually doesn't.   In about 45 minutes to a hour, it's time to take the chimneys off, carefully remove the sticks under the barrels, and smother the fire by putting the lids on (throw a little dirt around the bottom edge of the barrel and chunk something on top of the lid to make double sure it's airtight).
I hope this encourages anyone reading this to try making their own version out of whatever they have laying around, even though it's technically a type of rocket stove, it ain't rocket surgery.


  1. I was thinking today that it would be pretty cool to sit on my deck and watch flames shoot out of a TLUD in the garden at night. I certainly have plenty of debris to clean up. When I get a chance, I'm going to scrounge around and make one of these. The only thing I may have to get creative with is a tight lid.

    1. As hot as the barrel gets, I've been wondering if the barrel would glow red hot at night. A glowing red hot barrel with a low roar and flames shooting up out of it might be more interesting to watch than a bonfire.

      I'd bet that a flat piece of sheet metal with some bricks or concrete blocks to hold it down would be tight enough to use as a lid.

      Blocking the air flow coming in from the bottom of the barrel is as important to smother the fire as putting on the lid, and it's as easy as piling some dirt all around the bottom of the barrel to stop that airflow.