Charcoal vs Coal

[John McPherson]

It is an issue of availability and density.

Until railroads crossed vast distances, shipping coal mined from the ground in a horse drawn wagon was not cost effective. Most of the early iron furnaces in history were locally fueled by burning thousands of acres of forest in rotation. There are also historical records of blacksmiths blocking public roads by erecting a charcoal burn pile in a public right-of-way when their supply ran out.

Density because coal has had all of the air space crushed out, and wood charcoal is 'fluffy' by comparison, about a 10:1 volume comparison by weight. Too much air will literally blow the burning charcoal out of the firepot, you have to be gentle with the pressure. A five gallon bucket of good nut coal will last me all day, you might need a 55 gallon drum of wood charcoal to accomplish the same amount of work.

[Blake Laperriere]

Thanks a lot.  It is true that I will burn a lot of charcoal for a day of forging and that it is so light and fluffy.  I don't have a problem with the charcoal blowing out of my firepot.  I would guess that there just isn't the required amount of wood to make charcoal in most places.  

[ThomasPowers]

Historically charcoal was *THE* fuel for smithing until the high/late Middle Ages in Europe, (Gies & Gies, "Cathedral Forge and Waterwheel")

Easily made near the place of being used, can be done using coppiced wood.  Why the change?  Deforestation. Some of the earliest ecological laws dealt with banning of new iron smelting setups in the Forests of England as they were running out of wood for building ships for the navy! As wood became more expensive coal became economically viable IN SOME LOCATIONS, charcoal has continued to be used in many places all over the world due to the costs of coal shipping and procuring.

Even with the partial change over taking place in Medieval times iron was still smelted using charcoal up until Abraham Darby figured out a way to use coal by coking it ahead of time in the 1700's.  The big problem with coal is the sulfur content which is very bad for steel making it hot short and brittle.  Which is why the top grades were still smelted with charcoal even into the 1800's  "Charcoal Iron"  from Sweden was famed as the best you could get and was often specified in contracts.

Note that in medieval documents reference to "coal" meant charcoal and the mined stuff was designated as stone coal, pit coal, sea coal (it would wash up on some beaches from wave action on offshore coal seams), mineral coal, etc.

With modern transportation---a lot of which was used for coal, (barge, train, etc) and the high amount of labour involved in making charcoal, economics have flipped so coal was cheaper.   Good Knifemakers make sure that their coal is well coked driving off sulfur before letting it get near the blade steel.

The switch to smelting with coal is also why pretty much every steel has Mn added to it as it scavenges sulfur form the smelting process with coke.

[Blake Laperriere]

Thanks a lot, Thomas.  That is what I kind of thought.  Not enough trees for wood.  I have noticed that charcoal burns so cleanly whereas, as I have observed from the little coal I have burnt, it puts off a lot of smoke and doesn't seem to be clean burning.  

[Michael Cochran]

6 hours ago, ThomasPowers said:

coppiced wood

Thank you, Thomas, for another addition to my vocabulary.  

[ThomasPowers]

Common method of "farming" wood in earlier times; faster turnover times for commonly used shapes. I've made use of "coppiced" wood in modern times; back in Ohio under high tension powerlines where they would cut down all the trees and they would re-sprout and grow until the next time.  Great source of ash saplings--it was several decades before the Emerald Borer issue.  Then when making wattle panels down here; they would "mow" the sides of irrigation canals once a year or two creating a lot of nice springy straight "shoots" to weave panels from. (Mainly willow and salt cedar).

For my demos I like to use wattle panels to keep my smithing space to myself so to speak...

[Blake Laperriere]

57 minutes ago, ThomasPowers said:

Common method of "farming" wood in earlier times; faster turnover times for commonly used shapes. I've made use of "coppiced" wood in modern times; back in Ohio under high tension powerlines where they would cut down all the trees and they would re-sprout and grow until the next time.  Great source of ash saplings--it was several decades before the Emerald Borer issue.  Then when making wattle panels down here; they would "mow" the sides of irrigation canals once a year or two creating a lot of nice springy straight "shoots" to weave panels from. (Mainly willow and salt cedar).

For my demos I like to use wattle panels to keep my smithing space to myself so to speak...

 

That is awesome.  All that good wood.  I wish I had some good hardwoods here.  Only alder and a little bit of ash and of course alder isn't very hard.

Thanks Thomas

[JHCC]

Alder does make good charcoal, though, and it coppices well. If you cut it back when the shoots are about 2-3" thick, they will grow back quickly, and you don't have to chop it up too much before it goes in the forge.

[Blake Laperriere]

Sounds great.  We do have small alder all along the sides of the roads here.  It would be pretty easy to get.  Thanks a lot for your advise!

[Charles R. Stevens]

Alder charcoal was involved in the Viking conquests...

copicing is still used in England and Japan, one as it is a "green" material and as to the other, charcoal making (wich the Japanese practice as an art)

I use mostly charcoal, and one will be surprised how much steel one can burn up with softwood construction scraps. 

Mic one is looking for modern dissertations on charcoal making check out the black powder forums. Very high quality willow charcoal is one of the 3 base stocks 

[Blake Laperriere]

That is for sure.  I have burnt a couple pieces that I didn't want to burn!  You pre-burn the wood into charcoal before you use it in your forge, right.  I mean you don't just put the wood right into the forge and then forge in the coals?

[Charles R. Stevens]

Depends, my small sideblasts I use embers from a fire, or pre made charcoal, wile my v bottom bottom blast I just like the cigaret pack sized scraps on top and forge in the embers underneath. 

The v bottom is very fuel hungry and only effecent for large forgings.

 

[Blake Laperriere]

I have a small bottom blast made of an old brake drum with a plate welded to the bottom.  I cut some holes into that plate for the air to come in.  The firepot is about 12 inches wide by 3 inches deep, so I can't really burn whole pieces of wood.  I make it into charcoal first for this reason.