The idea to make charcoal from willow I read about first in The Materials and Techniques of Medieval Painting (Thompson 87) and the medieval method explained in Il Libro Dell'Arte (Broecke 54, 55). I watched this youtube video and read of a few other methods online. I was complaining to Jack, a blacksmith from Kennebec River Forge at the Great Falls Ballon Fest Ravensbridge demo that I needed a friend who had a big yard who frequently made fires that I could use as my oven and he suggested I should 'do what the boyscouts do and make use of a camp stove'. Encouraged by almost any suggestion of successful experiments these days, I went for it!
Follow my example AT YOUR OWN RISK. Charcoal is possibly carcinogenic as is breathing smoke. Use a well ventilated area and gloves.
On August 27, 2015 I whittled all the bark from the branches I had saved, cut them into pieces that would fit in a tin I got from Goodwill. Punched two holes in the top of the tin lid with a hammer and small nail for the smoke to escape.
I cut the whittled willow branches into pieces that would fit in the tin, one layer at a time, setting each layer perpendicular to the last until the tin was full.
Wiring it shut, I set it on my Coleman grill. Safety, safety, folks! I made sure my hose and fire extinguisher were ready.
After calling the Fire department to give them a heads up about the mysterious smoke I was going to create, I turned the stove on, with a fairly low flame. In several minutes it began to smoke and continued to smoke for about an hour!
Around minute forty-five I turned the flame higher. Not much changed after this modification. I let it cook until I saw no more smoke come from the holes, shut off the stove and shoved two bamboo skewers in the holes in the lid to deprive the system of most of the oxygen.
And Voila! Charcoal to draw with!