Using an old paint can as a retort is an easy way to make small quantities of Bio-char for use around the homestead. I use char mainly to add to the cover material mixture that I make for composting because it's great at absorbing odors. But it has many other uses as well.
The messy part is cleaning out the old, dry paint. But if you find one that has been mostly emptied by the paint brush, it's usually pretty clean and the first fire takes care of the residue.
Here I made some Bio-Char mostly from the spiky little balls from the neighbor's Sweetgum Tree, some twigs and part of an avocado seed.
There is zero ash and the best part is that you can burn stuff that is usually a pain to burn in a regular fire or a TLUD.
To make sure the can doesn't blow up, it's advised to punch a tiny little hole in it. But frankly, mine have always vented around the lid without a problem. I simply put the can into the center of the fire area making sure that the escaping gases will be directed downward and inward toward the fire. The gases, (smoke) that is forced from the can help feed the fire.
At first I was confused as to how you lit the fire in the paint can, until the end when I realized you stick the whole thing in there! Interesting.. so you don't even directly ignite the materials. So if I understand correctly you make vent holes and then you put the lid on top? What is the reason for the lid if you don't mind me asking? And how do you ensure that the escaping gases from the can are directed downward? Thanks for humoring my newbie questions
The reason for the lid is that you don't want a lot of oxygen. Otherwise the material will continue to burn and turn into ash.
It's not always easy or necessary to direct the gases downward but if the gases/smoke don't ignite, it doesn't feed the fire and just makes it more smoky. With a big fire it's not really a problem.
Thanks for that info.. I am now more informed about making biochar!