Full Chisel Blog

February 26, 2011

Charcoal, the dark side of wood, et al.

Filed under: Finishing,Historical Material,Of Interest,Techniques,Uncategorized,Wood — Stephen Shepherd @ 7:41 am

 Calling all colliers.

Charcoal is not the first thing you think of when thinking about wood.  Charcoal is the very last thing you think about wood in the smoldering fire.  However, charcoal has served and continues to answer a good purpose.

Charcoal is made from many different high carbon containing material such as wood, leather, bone, grape vine, peach pits, cork, natural fibers to name a few sources for making charcoal.  These materials are calcined, heated in the absence of oxygen, which drives off the volatile gases in the form of smoke and leaves pure carbon.

I simply put the material tightly packed into a metal container with a tight fitting lid.  In the center of the lid is a small hole to relieve pressure and allow the gases to escape.  It can be a small round tin or a large metal bucket with a proper tight fitting lid and a gas escape hole.  The container is then placed over a fire source.  Putting them in outdoor controlled fires such as a fire pit allows the gases to be consumed.  Cooking the stuff indoors is not recommended without adequate ventilation.

As the container heats up smoke will start coming from the gas escape hole and will ignite on the outside of the container.  The hole needs to be small enough to prevent the fire from going into the container, but I have never had a problem.  A well packed container helps prevent that problem.

After the smoke subsides, the container is removed from the heat source and allowed to cool before opening, which should be done away from any open flames, just in case there are gases that might ignite. 

After it has cooled, I open the container and make sure everything is black.  I may have to rearrange the contents and repeat the process if some of the material is left unburned.  Be careful when using cork as a material because it can expand its volume and pop open the container.  Also make sure you don’t use composite cork, the stuff that is real cork ground up and glued back together.

Some materials like peach pits require a long cooking time, but there is a reward of a particularly sweet smell when burning.  Some materials like bone, ivory and leather have very disagreeable odors and these are best burnt outdoors with good ventilation.

Hardwoods do make the best charcoal, but softwoods can be made into charcoal, the yield is just less.  Alder is the choice for making the charcoal for gunpowder and willow [the twigs] are used for making artists and drawing charcoal.

Animal charcoal is made from bone and called ‘bone charcoal’ or ‘bone black’, made from ivory it is ‘ivory black’, ‘char’ or ‘spodium’, it is also made from natural sponges which contain a small amount of iodine.

Grape vines and most herbaceous plants can be made into charcoal.  As mentioned before cork is an excellent material, called ‘Spanish black’ it is very fine black powder pigment.

Charcoal has many uses from the mesquite hardwood charcoal that fires up the barbecue to the charcoal filter for your drinking water; you can even brush your teeth with the stuff.  Used to deodorize cisterns and can be used to deodorize smoke damaged furniture.  

Charcoal was the fuel of the nineteenth century industrial revolution; heating the forges, smelters, steam engines and furnaces.  Charcoal has had a long history of providing heat, it is a more convenient way to store wood and when consumed produces a lot of heat and little smoke.

It is a writing and drawing material, great in place of graphite that might interfere with gluing or finishing. By dipping the charred willow stick in beeswax it produces a black crayon. It can also be easily and finely powdered for a pounce bag to lay out pounce wheel perforated paper patterns and it is a good black pigment that mixes with any binder to make paint or stain, as well as being colorfast.

By burning pure cotton or linen fabric in a small container with a hole, you can make ‘char cloth’ that easily catches a spark for flint and steel fire-making.

And do not forget a light toasting to the inside of a wine barrel adds to its flavor and the charring on the inside of whiskey barrels adds to the flavor and color.

Store charcoal in an airtight container because it will pick up and absorb all odors.  This is why you can put it in the drawers of a cabinet to remove cigarette or smoke damage smell.  When you are done, the charcoal can be used on the barbecue as the odors are burned off before the food is cooked.

I am curious how the scraps and shavings of Kauri will char up?  Would be nice to have some paleo-pigment, other than dirt.

Wood may be the fuel that heats you twice; once when you cut it and again when burned.  Charcoal is the fuel that heats you at least three times, when you cut it, when you char it and when it is finally burned.

My shop no longer generates wood scraps that need to be disposed of.  I now convert them into charcoal and cook up a pork chop on my charcoal brazier.

 

Stephen

6 Comments »

  1. But did you use the flint and steel to start the fire for the pork chop?

    Cool stuff. I remember plenty of times making char cloth, but hadn’t thought of the bone black in the same way.

    Comment by Ken Pollard — February 26, 2011 @ 9:33 am

  2. Ken,

    No, I used a burning glass and char cloth and an accelerant. Delicious.

    I make a char cloth that is impregnated with niters, catches fire every time, difficult to extinguish.

    I have some scraps, shavings and dust from bone and ivory and plan on making those into pigments. The cork is amazing stuff, really dark and very fine. Had a slight conflagration when the cork expanded and popped the lid.

    Stephen

    Comment by Stephen Shepherd — February 26, 2011 @ 2:42 pm

  3. Perfect, just perfect timing. I have a growing supply of small scraps, and I was thinking of just burning them. Thanks for the detailed instructions!

    Comment by Federico Mena Quintero — February 26, 2011 @ 8:40 pm

  4. All that just to show off your new brazier! 🙂

    Neat article. I have been thinking about making some charcoal, say maybe a barrel full for cooking purposes or for sale.

    Luke

    Comment by Luke Townsley — February 27, 2011 @ 4:09 pm

  5. The traditional method of making charcoal from wood is by burning. The wood is put in an almost sealed container, or the outside of a pile of wood is covered with earth and other materials to seal it. The pile is then burned with just enough oxygen present for the gases to burn, heat the wood and drive off more of the gases, but not enough that the fire is hot enough to burn the resulting charcoal.

    Kingsford brand charcoal originated in the 1910′ or 1920’s as a by-product of Ford Motor Company’s sawmill in the upper penninsula of Michigan.

    Comment by David Cockey — February 27, 2011 @ 7:03 pm

  6. […] covered making Charcoal here and briefly mentioned the pounce wheel and pounce bag.  I covered it more depth in Shellac, […]

    Pingback by Pattern layout using a pounce wheel & pounce bag « Full Chisel Blog — August 15, 2011 @ 1:18 pm

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