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.
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).