With the spring here it was time to prune back the old growth on my vines so that younger, grape bearing vines could replace them. As I was carefully choosing and pruning, my son came up asked asked what I was doing. I told him, and added that such old vines would make very fine charcoal sticks … well, with that little nugget divulged, he immediately wanted to get to work creating his own drawing charcoal.
Making drawing charcoal isn’t difficult. Once the vines are cut to the right length, they need to be heated in an anaerobic environment (if oxygen was present, they would turn to ash rather than carbon). Both of my older children got involved and helped prepare: the vines were trimmed, extra bark was removed, and they were carefully packed into a couple of old metal pipes.
While all this was happening I got a fire going in our little pit our behind the house. This had a double purpose: not only would it fire our charcoal canisters but the extra vines that we couldn’t use could burn and help in the heating! With everything carefully sealed up, we dropped the canisters into the hot fire.
After a few hours the fire had died down and we fished them out of the pit. At this point they were still very hot (somewhere above 550°C, which is the upper limit of my infrared thermometer). It took them a good hour to cool down below 100°C and then it was time to open them up and see what we had created.
With the canister open, we found the thin, black sticks of charcoal we were hoping for. They had lost much of there mass (mainly due to moisture loss) but what remained was carbon-black and ready to draw with.