One of the draws of this type of craftsmanship is the deeply ingrained appreciation for ‘real’ and natural materials and simple methods. Many of the shop operations depend on human power and handwork. The charcoal fuel for forging is made from reclaimed wood.
Fire it up!
One of the main sources of energy for a blacksmith shop is the fuel for the forge. Many modern day ‘smiths use propane or natural gas forges which are very efficient but need different care and operating conditions to the traditional forge. In North America and Europe, ‘smithing has relied largely on high quality metallurgical grade soft coal since the decline of the European forests and the discovery of abundant coal supplies. In other places in the world, including Japan, the long-standing tradition of forging with softwood charcoal still stands.
Propane and Natural Gas
Propane and natural gas forges are relatively clean burning and well-suited to tasks such as forge welding and other operations where cleanliness is paramount. Storage and operation pose different safety issues than solid fuel sources, and gas forges tend to be highly oxidizing on the work surface. I feel that gas forging has its place in certain shops for certain tasks, but would not personally want to run a gas forge all day for the work I do.
Good Old Bituminous Coal
Coal is a useful material for building and controlling a good forge fire as it can be shaped and managed with water to create a self-enclosing oven that focuses heat on the work. Another positive is that it is relatively hard to light in solid form, making it safer to store and use. The major downside of forging with coal is that during the coking phase of the burn, the impurities that come out can be hazardous to respiration and nervous systems over long periods of exposure. Forging with pre-made coke instead of coal protects the smith from direct exposure to these chemicals but does not prevent them entirely. Another issue for today’s smith is that proper quality and purity of blacksmithing coal is not always easy to obtain. After many years of using coal I still enjoy the smell and feel and understand its behavior well, but am willing to adapt to a new fuel for the sake of health. (update: after using charcoal for several years now I would never want to go back to coal)
In times past, charcoal was the fuel of choice for cutlers, sawyers, and other smiths who wanted to work with fine steel. The finest tradition of edged steel artistry belongs to the swordsmiths of Japan, and their work has always been done with pine charcoal. For the average ‘smith today, unless you live in Japan, there are few sources of properly cooked softwood charcoal. Fortunately, in contrast to the long, labour intensive, and smoky pit methods of the past, there are methods of producing quality batches of charcoal in a relatively clean and efficient manner.
Using a small amount of firewood, dry wood cutoffs from construction waste, are heated inside an enclosed container until they begin to give off their gas and impurities. The gas is vented out the bottom of the container back into the heating fire at which point the system becomes self-sustaining and the wood gas given off supplies the heat to continue the process to completion. Once this clean-burning fire goes out, the container is left to cool over night before opening and chopping for use. A record of the subsequent journey is here: All posts tagged Charcoal.
The traditional method over most of the world was the direct method, a controlled burning with both the fuel wood and charcoal wood in the same space (a pit/mound in the west, a brick kiln in Japan). This method is long, smoky, and requires skilled tending. Most of the modern small-batch methods rely on the indirect method, sealing the charcoal wood off from the oxygen and the fuel wood. Though retort (indirect) methods can be used with some success, the resulting charcoal is often overcooked and better suited for use as biochar.
The best small batch method I have encountered is Iwasaki~san’s design based on the traditional Japanese kiln, and is a hybrid of direct and indirect methods. In this design, built from reclaimed 55 gallon drums, the fuel wood is separate from the charcoal wood, but the flue gasses pass directly through the charcoal wood while cooking. Watching the colour and characteristics of the smoke allow a very accurate cooking time to be determined. More information on the development of this kiln here: Charcoal Kiln 3.0.
An apprentice to a Japanese swordsmith might expect to spend his first three years practicing the art of properly and efficiently chopping and sorting charcoal for various forging and welding operations. The Soulsmith Pierre demonstrates and discusses Sumi-kiri, the art of charcoal cutting from the perspective of an apprentice.
Read: Sumi-kiri san nen…