Hi Folks, While we are on the subject of Charcoal. Does anyone
know how to make it? It can’t be that difficult. Perhaps the Good
John Burgess? I still have access to those zillions of trees that
my neighbor knocked down. Susan
Heat wood in the absence of oxygen. That usually means some sort of
closed box. Without oxygen, although the organic compounds in the wood
break down, they only “distill” and break down, they don’t burn (no
oxygen.). the result is charcoal. If you’ve set it up right, the
gasses that come off can be condensed into things like turpentine,
etc. Don’t go asking me for exact temps. You don’t need em, and I
don’t know for sure. Hot enough to burn, if it had oxygen. Used to
be done by piling wood into a tight bundle, covering with dirt, then
building a bonfire over the pile. Now it’s done in ovens.
Peter Rowe
Susan - Why would you want to bother? Surely you can do more
valuable work at the bench with the time and energy it would take to
make charcoal, no? Charcoal is formed by the incomplete combustion of
wood - so put some in your kiln and heat it until all the volatile
gasses are driven off, but don’t give it enough Oxygen to support
combustion and Voila’ - when it cools you’ve got charcoal. Or, just
start a big bonfire, and after it gets roaring real well, bury it
quickly. Again, wait for it to cool and dig out your charcoal. The
process is identical to turning coal into coke - perhaps someone in
your area has a coke oven you could visit for a more complete
understanding of the process. If there’s any iron smelting / steel
making going on near you, they’ll know all about coke. But pay the
charcoal maker his just wage and put your energy into your jewelry.
The world will be a better place for it.
Mike
Chastain, Charcoal is made by decomposing wood with heat in the
ABSENCE of oxygen. If air or oxygen is present, the charcoal itself
will burn away as any weekend Bar-B-Que chef will attest. Try this:
Cut the wood into pieces of the desired size and place them in an old
coffee can (or similar). Fill the can with sand until the wood is
COVERED by at least 3". Take the can outdoors and place it on a
hotplate at its highest setting. After a while the mixture will smoke
like crazy. The smoke is flammable and and has a choking odor so be
sure there is a decent breeze to blow the smoke away you and your
studio. When the mixture has completely stopped smoking, (this may
take several hours, depending on the amount of wood and heat you use),
remove the can, allow it to cool, and dump the contents. It will help
if you can wrap the outside of the can (not the bottom) with some
scrap fiberglass insulation to keep the breeze from cooling the can
too much. Unless you have need for special sizes or manny pieces of
charcoal, I’m not sure it’s worth the trouble. Rio Grande has charcoal
blocks in several different sizes at fairly reasonable prices. Your
choice…Bob Williams
Hi, Susan! I’ve never made charcoal blocks, but I understand that
charcoal is made by heating wood in the absence or air (I guess so it
doesn’t catch fire). Lindsay Publications had a couple of books or
pamphlets available about it a while back - maybe they still do(?) One
was about making and/or using a “charcoal kiln”.
http://www.lindsaybks.com/ There is an (I believe) explosive gas
given off when wood is heated in this way (process is called dry
distillation(?)) so for goodness’ sake, be careful - outdoors seems
like the the only safe place for this work, and I imagine there are
precautions that must be taken. Lindsay had a book a while back -
maybe still do - about how this gas was used to power cars! Book was
called “Producer Gas” I think. Good luck and be safe! -Dan Weinstein
Chastain, Charcoal is made by decomposing wood with heat in the
ABSENCE of oxygen. If air or oxygen is present, the charcoal itself
will burn away as any weekend Bar-B-Que chef will attest. Try this:
Cut the wood into pieces of the desired size and place them in an old
coffee can (or similar). Fill the can with sand until the wood is
COVERED by at least 3". Take the can outdoors and place it on a
hotplate at its highest setting. After a while the mixture will smoke
like crazy. The smoke is flammable and and has a choking odor so be
sure there is a decent breeze to blow the smoke away you and your
studio. When the mixture has completely stopped smoking, (this may
take several hours, depending on the amount of wood and heat you use),
remove the can, allow it to cool, and dump the contents. It will help
if you can wrap the outside of the can (not the bottom) with some
scrap fiberglass insulation to keep the breeze from cooling the can
too much. Unless you have need for special sizes or manny pieces of
charcoal, I’m not sure it’s worth the trouble. Rio Grande has charcoal
blocks in several different sizes at fairly reasonable prices. Your
choice…Bob Williams
Another more interesting way to GET charcoal blocks is to fly to
an SE Asia country like where I live, Vietnam, and go to the
local market and buy several charcoal logs for about 10 cents
American. When I say logs I mean logs. I can carry only two at a
time in my arms. They are used locally as their cooking fuel for
most houses and rstaurants and such. Then take them home and saw
as many blocks as you will need in 5 years. No need to be extra
careful and wire them together because they are some what
costly. Just solder away and get better results than from other
materials. My students loved sawing and sanding them flat last
month when I decided to do this. Its even helped tame that
nasty firescale. 
Sharron in sunny
Saigon
Hello, At Home Depot and elsewhere too I have bought bags of charcoal
(not the briquettes but the real stuff) for barbecuing meat on my
outdoor grill. I found that a lot of the pieces in the bag were useful
for melting gold on. They were not cut into neat square blocks like
you get at jewelry supply stores but they were just as useful for my
needs.
Len Carlson
-
When I was a child about 60 years ago, my father took me to an
outdoor charcoal factory in Germany. The workers chopped wood and
stacked the pieces with spaces between in a circular pile with a
rounded top. Then they covered the pile with sod and sand and placed a
few vent holes. They somehow started a fire in the lower section and
then let the pile “simmer” for several weeks before harvesting the
charcoal. -
During WWII, trucks in Germany (and other countries also) were
equipped with wood-gas generators. They were the size of a water
heater and attached behind the cabin. The driver had to fill them with
wood, start a fire and reduce the air flow to generate the explosive
gas that was piped to the engine to serve as (poor) gasoline
substitute. I assume the driver removed charcoal after a trip before
he filled the chamber with wood again.
Dietrich
There is an (I believe) explosive gas given off when wood is heated in this way (process is called dry distillation(?))
G’day; If you are really interested, some of the older chemistry
textbooks give details on the dry, destructive distillation of wood,
including exactly what happens to it. As many Orchidists wrote,
charcoal is made by heating wood in the absence of air. But;
‘Charcoal burning’ is a very ancient and skilled craft, involving the
careful selection of the right kind of wood, stacking it very
carefully in the right pattern, (or it will either burn hot, which
isn’t wanted, or the fire will go out and the stack will have to be
dismantled). A hole is left down the centre of the stack for the
escape of gases, and cunning inlet holes are left to supply just
enough air to keep up the heat. The whole heap is covered in turves,
after ignition, and left for several days, sometimes weeks to quietly
smoulder-burn, although the charcoal burner has to sometimes control
the burning rate by opening some holes more, and closing others. The
charcoal is available when the stack has sufficiently cooled and is
opened. But what of the gases evolved? Well. there is a very large
variety and include carbon dioxide, carbon monoxide, acetic acid,
acetone, methane, methanol, several different phenols and tar (sold to
this day in pharmacies and called Pine Tar Sol to help in skin rashes
which itch) small amounts of hydrogen cyanide and many other items,
not forgetting turpentine. It certainly isn’t worth the amateur’s
trouble to try do-it-yourself charcoal burning. In most petrol
(gasoline) stations in New Zealand, bags of charcoal are readily
available for barbecues, at a low cost. The charcoal blocks used by
some jewellers are not quite the same though. These are made by
adding a small amount of a binder to powdered charcoal (sodium
silicate solution , or even certain fine clays) compressing it into
blocks, then gently heating to activate the binder and remove
moisture.
I personally think that the jeweller’s supply houses seem to charge
too much, far, far more than when I used to buy them by the hundreds
for use in 1st year chemistry labs as part of a course in simple
analytical chemistry. (not done these days!) There; more than you
ever wanted to know about charcoal! Cheers,
John Burgess
Johnb@ts.co.nz