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I Forge Iron

Switching from coal to charcoal


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Funny all the old wootz steel was MELTED using only charcoal; I guess they didn't know it didn't get hot enough...

 

Sounds like you were using it in a forge designed to use coal or coke.  If so then saying that it's not a good fuel is like saying that diesel is worthless cause you tried it in your gas powered car and it didn't work worth beans...

 

Thomas, as one pedant to another I wonder if you would like to point out where I stated that charcoal is not a good fuel?

My argument is that it is not the best fuel available.

Use it if you want, or if you have to. Don't use it based on some peculiar ideal or notion not based on experience.

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I dunno, Andy. I've never seen anyone do serious smithing with charcoal except youtube videos of japanese sword makers (and they are using mountains!). As I believe I've said, it's an interesting and rewarding fuel to use, and one I have used a lot, but it has vey serious limitations. I like to work mild steel at almost a dripping heat, which is just not possible using charcoal. Welding anything over about 16mm is also going to be a problem just from the sheer volume of fuel you will need. And doing anything resembling a production run becomes a problem because the charcoal gets pushed about, and the heat dissipates while the charcoal that you don't want to be on fire burns merrily away. "Fire flies" have nothing to do with it.


I think that's probably down to ease of getting the fuel than anything else. If you have cheap and easy access to coal/ coke then fair do's.

I wouldn't say it has limitations, it just requires a different way of working.

FYI, in my early days I've melted, burned and otherwise ruined plenty of steel in a charcoal fire. Indeed we often make blacksmiths sparklers for demos. - Saying you can't get steel to "dripping" heat is simply not true.

Granted for bigger stock you will need to put some more fuel on. But I've forged 1" round without issue.

Andy
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DanP: "I like to work mild steel at almost a dripping heat, which is just not possible using charcoal."  right there!  

 

Charcoal was a traditional fuel for real wrought iron which is often worked at temps where mild steel is burning.

 

Charcoal has about the same BTU content per *pound* as coal but is a lot less dense and so you do go through a lot more.  Your forge needs to be tweaked for charcoal though with a deeper and narrower firepot and A LOT LESS AIR.  When I have to use a coal forge with charcoal I use firebricks stacked up to control the size and depth of the fire and don't have excess charcoal on the forge table as it will start to burn and just be wasted fuel and heat.

 

I agree that using a standard coal forge with charcoal is not the way to go---especially if you have an electric blower!

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DanP: "I like to work mild steel at almost a dripping heat, which is just not possible using charcoal."  right there!  

 

Charcoal was a traditional fuel for real wrought iron which is often worked at temps where mild steel is burning.

 

Charcoal has about the same BTU content per *pound* as coal but is a lot less dense and so you do go through a lot more.  Your forge needs to be tweaked for charcoal though with a deeper and narrower firepot and A LOT LESS AIR.  When I have to use a coal forge with charcoal I use firebricks stacked up to control the size and depth of the fire and don't have excess charcoal on the forge table as it will start to burn and just be wasted fuel and heat.

 

I agree that using a standard coal forge with charcoal is not the way to go---especially if you have an electric blower!

 

Thomas, I am afraid all I have to offer is my (professional!) opinion, no matter what factually erroneous red-herrings you choose to throw into the mix. 

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What factually erroneous red herrings?  *You* are the one who said "I like to work mild steel at almost a dripping heat, which is just not possible using charcoal"  which *is* factually erroneous.  Perhaps you meant to say "which is just not possible using charcoal using my set up and methods".  In which case it would be experientially accurate for you.

 

If you like I can provide the cites on using charcoal to melt steel---It's in "Crucible Steel in Central Asia", a doctoral thesis by A. Feuerback,  IIRC off the cuff. 

 

If you would like one on the forging of iron/steel with coal, "Cathedral Forge and Waterwheel", Gies & Gies, discusses when coal started to be used for smithing (high to late middle ages) and IIRC FoxFire #5 mentions it's use in smithing in America till pretty recent times.  (Living Treasures of Japan, National Geographic, show the use in modern times for swordforging) In smelting,  Abraham Darby at Coalbrookdale, England, in the 1700's helped pioneer the commercial use of coked coal in smelting iron.

 

AS for BTU's per pound:

"United States Department of Agriculture Forest Service publication How To Estimate  Recoverable Heat Energy in Wood or Bark Fuels brochure lists the following woods with 8,000 BTUs to 12,000 BTUs."

 

"In 2012, the average heat content of coal produced in the United States was about 20.14 million Bristish thermal unit (Btu)" (from the US Energy Information Administration at www.eia.gov) [which would be 10,700 BTU/pound]

 

My comments on using forges built or tweaked for the use of charcoal are strictly empirical as I often bring/make a forge based on Y1K examples to medieval events---two single action bellows without check valves (Theophilus doesn't mention check valves WRT metal working bellows though he did mention them WRT bellows for the portative organ, so he knew about them)  Side blown and built of adobe/fire safe rocks on a soapstone slab.  I generally do at least one forge weld each time to show people that charcoal will work.  It does take different work methods including keeping the piece off the forge floor while charcoal is forced beneath it as it burns away.

 

If you can point out my errors I would be most interested in correcting them!  If you know sources that contradict mine *please* let me know;  I bought another bookself recently as I know have two houses to spread them around (even took the one blocking the window in my study to the new place) and can always add some more books to my hoard.

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Take it easy, Mr. P.

What we are talking about is someone looking for a fuel source in the here and now.

My professional opinion is that charcoal is not a first choice, when there are many others and better. All have their pros and their cons. That is all I have to say on the matter. But; If you would like to blather on about whatever fuel the Phoenicians (or whoever) used until you are quite blue about the gills, that is your choice.

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better in this case is :-

 

Cheaper  in the uk coke is £450 a tonne( int north coal is much cheaper I have seen £250 a tonne), charcoal £750 to £1200 a tonne.

 

If you are a hobbiest then you can make it but at a blacksmiths rate I would dread to think what charcoal would cost.

 

Much less hassle to use (coke and coal form easy to remove clinker as opposed to all the ash from charcoal so no shovelling out the fire after a few hours burn.

 

hotter (in the real situation of a modern forge).........I know you can smelt with charcoal  etc. I know its theoretically hotter, but you end up having to run such a big charcoal fire to equal a small coke or tiny coal fire its a little ridiculous if there are other options.

 

I find charcoal smokier than coke not as bad as coal.

 

I use

 

 around a tonne of coke a year.......

 around 650kg charcoal (for smelting and lighting the coke fire)

and around 1500 to 2000 kg of propane...............

 

If I did not smelt I would not use much charcoal.  just a bit to light the forge and cook steak.

 

 

The vast majority of modern western smiths use  fossil fuel other than charcoal for these good reasons.............and probably others too.

 

At a pinch charcoal will certainly do the job.

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If you had a decent retort(pretty much smoke free, costs less than 20quid in scrapyard materials and takes about 3hrs to make) a source of old pallets or builders/chippie's lumber waste  you might use a dash more charcoal, just saying!

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While there is lots of good and bad information be bandied about here about fuel choices what really makes the the difference is the fire pot style.  A side draft narrow fire pot will make the use of charcoal a pleasure while a wide bottom draft is a lot of work and uses more fuel.

If a guy was serious about charcoal and had the means to make his own and had a good side draft he would be good to go.

I think the ratio of charcoal to coal is about 8 to 1 and is even greater with coke.  

If I had it to do all over again I would set up a side draft and use coke for general work and charcoal for PW.

It really depends on what a guy is doing and the size and quantity of work.  If I was still doing industrial work I would be using gas and an induction heater.

But the work I do now demands coal or coke.  I use both.

But as i said before, if I had to do it over it would be different.

There is no better or worse.  It is a matter of economics and availability.

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  • 4 weeks later...

For a 2" tuyere in an 11" brake drum forge what size holes and how many do you want in the grate?  I've successfully forged welded w/ coal, coke and a mixture of coke & charcoal, but haven't been successful FW'ing on charcoal alone.  I've deepened my firepit by using firebrick, also tried with and without a piece of charred wood ontop to create a cave of sorts.  The charcoal I'm using is homemade from dead oak trees behind my house.  The flux I'm using is straight borax.  Seems like it's getting hot enough as I've burned up steel with the setup, thinking that maybe some of the charcoal pieces are too find and end up dirtying the weld?  My thinking for this is because when welding with coke I was only successful with a new fire, after having cleaned out the pot of all ash & clinkers.

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  • 4 weeks later...

I've been using charcoal for a bit now.  My firepot is deep and bottom draft (the Centaur Forge coal firepot), so maybe if I lined it with some refractory cement it would work more efficiently.  I have managed to forge weld, I made a welded hasp yesterday, but getting up to welding temperature was laborious and I had trouble getting a good weld, though I got there in the end.  With coal I was fairly confident in forge welding, but doing it in charcoal is going to take a lot more practice.  In general getting up to forging temp. takes more time it seems.

 

The major drawback so far is the sparks.  I'm using Cowboy brand (easy to get to start trying it), but I'll pay a few cents more for 20# next time.  The Cowboy stuff goes from hardly any sparks to a huge amount very suddenly, but the real issue is the sudden fireworks that erupt several feet from the forge.  This isn't an airflow problem, I've got the airgate almost closed and use a light hand on the blower, and the fireworks can happen even when there's no air at all.  Improperly charred wood or poor wood?

 

A smith I know is looking for people to go in on a coke order, so I'll probably get coke next.  The charcoal is keeping me running until then, though.

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Why not make your own charcoal?  I've planned on making a retort, which if you search the forum will find lots of plans for doing so but for now I just have a 55 gallon drum w/ 8 triangular holes cut into the bottom sides.  After I get a good fire burning w/ small stuff I load it about half full with larger chunks and let that burn for 45-60 minutes.  Then I cover the bottom holes w/ dirt and put a lid on the drum, next day I have charcoal.  Not as good of a yield as what others get with the retort, but I live on a green belt w/ loads of available wood and this is easy to do.

 

When using it I mix a little anthracite coal which helps keep down the volcanic action.  I probably should change my fire grate to use small holes vs. 1/4" bars & slots but this has worked so far and I can get to FW'ing heat w/o a problem.   I've also mixed industrial coke when available.

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My guess about the firework (of the jumping sort) is that it gets worse with moisture, bark and improper charring. It reminds me of a crackling woodfire.

I feed the fire much like you would a coal fire, pushing the dry, charred coals down and in from the sides. Also I pile on fresh charcoal if I know it's gonna be a few minutes before I crank the blower again.

I haven't been using water to douse the fire since I've got a rather narrow hearth with tall firebricks on either side, but I plan to start dousing in my next forge. I'm hoping this won't lead to more crackling fireworks, as my theory is that the problem is the trapped water within, and freshly added water will have a just as hard time getting into these enclosures as the steam has getting out. At least within this timeframe.

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I've been smithing in my area with charcoal and i can get the iron pretty hot,my experience with fireflies is using charcoal and not having my firebox full or dumping fresh charcoal directly on the forge area. i usually put fresh on the side then roll it over later.

 

as far as price,i get Roal Oak from walmart as of now(until i find a better source) for around 12-13 dollars for 2 20 lb bags

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