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Curiously looking at Centaur forge site.  They have "Coal" forges and "Coke" forges.  My question is, why would there be a difference?  I'm new to forging with coal but my understanding is as you tend your fire, the coal converts to coke and the coke is actually what produces the "fireball" in the fire pot where we do the actual heating of the metal.  I've just recently found a source for coal and in using it I have experienced that transformation from coal to coke (and clinker too).  So what would be the necessity of a "coke" forge vs. a "coal" forge?

Here's quotes from their site;

The coke forge- "The Heavy Duty Firebowl is cast an extra 1/4" thicker than the Centaur Vulcan or Mini firebowls to hold up to the higher heat when you burn coke."

The coal forge-  "The Centaur Vulcan Firepot is the most popular choice for blacksmithing, made to use with blacksmith Coal. You can burn Coke in this firepot occationally, but if you burn Coke regularly, the bowl will crack sooner."

So perhaps there is the answer to my question but still, is the coal not converting to coke and is that not what we are actually producing our forging heat with? 

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Industrial coke is a bit different than "breeze" coke made in the forge.  It's harder to light and to keep going---you need a constant air supply or it can go out while you are working a piece at the anvil.  So it tends to burn hot!!!!!!!!! and equipment for it tends to be heavier to last longer. (Also coke was/is more of an industrial fuel here in the USA and so equipment for industrial use tends to be beefier.)

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But these are 24" x 24"    "portable"  forges.  So I would not guess these to be industrial equipment.  Again though, there is a difference between coke and the coke that forms from burning coal in a forge?

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"Coke" basically means "Coal with the volatile elements cooked out." When soft coal cokes in the forge, you get what ThomasPowers calls "breeze" in his post above. However, the industrial coke he also mentions is not made from soft coal (aka "bituminous coal" or "blacksmith's coal") but primarily from anthracite (aka "hard coal"). That is why it behaves differently from the coke/breeze that forms in the forge. The "coke" that CF is talking about is the industrial coke.

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10 hours ago, JHCC said:

"Coke" basically means "Coal with the volatile elements cooked out." When soft coal cokes in the forge, you get what ThomasPowers calls "breeze" in his post above. However, the industrial coke he also mentions is not made from soft coal (aka "bituminous coal" or "blacksmith's coal") but primarily from anthracite (aka "hard coal"). That is why it behaves differently from the coke/breeze that forms in the forge. The "coke" that CF is talking about is the industrial coke.

Okay, so cooking down soft bituminous blacksmithing coal produces coke.  Cooking down hard anthracite coal (which isn't typically used for blacksmithing)  produces the "industrial coke" which burns and behaves differently.  

I assume it burns hotter, (?)  and using THAT would necessitate a thicker or beefed up firepot & forge components. Is this correct?  If so, it all makes sense now.

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Industrial coke is much more dense than breeze and so more BTU's per *VOLUME* and it is not made from anthracite!

"Coke is a fuel with few impurities and a high carbon content, usually made from coal. It is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulphur bituminous coal. "  Wiki

Since it takes a fairly constant airflow to keep it burning the heat output can get intense.  As I recall coke is a more common forge fuel in England than in the US.

Think of it like an engine where the coke one is running at top revs all the time and the coal one spens quite a bit of time at low revs; which would you expect to wear out first?

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7 hours ago, ThomasPowers said:

Industrial coke [...] is not made from anthracite!

Okay, my mistake. 

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A friend of mine works the towboats and barges on the Ohio R.  He came home from one tour with some bags of what they called "coke".  It was byproduct from some refinery/factory somewhere.  Smelled like petroleum, so I assume it was petroleum coke.  It didn't look like regular coke, but the lumps (about 1" diameter) were made up of tiny spherules, like oolites to us geological types.  The lumps were hard, not friable.  Tried burning it in the forge, but it didn't work.  The lumps burned up quickly, no discernable ash or residue and the fumes were not pleasant, so that stuff went by the wayside!!

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On 6/24/2017 at 5:38 PM, ThomasPowers said:

Industrial coke is much more dense than breeze and so more BTU's per *VOLUME* and it is not made from anthracite!

"Coke is a fuel with few impurities and a high carbon content, usually made from coal. It is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulphur bituminous coal. "  Wiki

Since it takes a fairly constant airflow to keep it burning the heat output can get intense.  As I recall coke is a more common forge fuel in England than in the US.

Think of it like an engine where the coke one is running at top revs all the time and the coal one spens quite a bit of time at low revs; which would you expect to wear out first?

Okay, now I'm confused again. "usually made from coal"...I thought it WAS coal, just coal that had converted to coke by burning. (?)  

(Burning wood converting to charcoal would be the closest analogy I could think of that would be a similar process.)  I'm still pondering using coke, specifically, as forge fuel.  Why? Does the coal not convert to coke and THAT is what produces the intense heat we use for forging? 

Why would one use coke specifically if the coal automatically converts to coke anyway? By that I mean, it seems it would add significantly to the cost if there is a process on a commercial scale to convert the coal to coke for the purpose of selling that instead of coal.  And if that is the case and coke is produced  and sold as cheap as coal anyway, then why offer coal for sale?

Either way, it brings back up the original question of why a heavier fire pot is needed for coke vs coal.     After all, starting the fire using coke or converting coal to coke in the same fire pot, what is the difference?             Hate to be dense but what am I missing here?

I'm going to assume the key word here is "industrial" coke.  So what makes THAT different if it is produced from the same bituminous coal?  The process?

 

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The original question was answered; several times: industrial coke tends to burn hotter and with continuous air is rougher on the firepot. So thicker/heavier firepots are made to use it. When you buy coke it's industrial coke and not the lighter and less "intense" breeze.  Coke made from coal in your forge sometimes will float in a bucket of water. Industrial coke sinks. Industrial coke is better for some processes and worse for others. For example a lot of us forge with hand crank blowers, with industrial coke you will have to have another person in your shop just turning the blower continuously---industrial coke can and will go out while you are working a piece at your anvil.  Using coal burning to coke this is not a problem.  Good smithing coal will clump when burnt making it possible to have a "closed fire" which many people prefer for forge welding---especially when they are getting started. Coke does not do this you can only get an open fire with it. Etc and so on!

As an analogy think of diesel engines and gasoline engines. Why do we have two different types?  Diesel is better for some uses and gas is better for others---you can do a lot of tweaking to try to get one type to work for the other use case but it's a lot simpler to just use the one most suited for the job.  Very few "hobby" smiths need a "16 cylinder diesel engine" in their shop.

Now why do they sell charcoal when you can just use wood to get coals for cooking over? Why do they sell charcoal briquettes when you can just use lump charcoal? Why do some people want mesquite for BBQing and others want apple?  WHY? WHY? WHY?

The "usually" is to deal with petroleum coke, not used much in the USA but used a lot in China---not necessarily for forging; but for home heating.

Considering you are quibbling over something people have been doing all over the world in a hole in the ground for over 2000 years; perhaps you should drop blacksmithing and try machining, it's a process where fussiness is considered a plus.

If this is so much a problem for you; why have you not asked around and got a bucket of coal and a bucket of coke and dug a hole in the ground and figured it out for yourself! Get off the net and *DO* *SOMETHING*!

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Petroleum coke is a high sulfur, low volatile species of coke. Extra desulfurizing treatment can be done but usually is not. Perhaps the effluent pollution standards are less stringent for home heating in China.

SLAG.

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(or non-existent) I remember reading about the US exporting petroleum coke to China where it was processed into blocks for home heating as well as other energy uses. Unfortunately it's been called dirtier than coal; but is not tracked like coal is.

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9 hours ago, ThomasPowers said:

The original question was answered; several times: industrial coke tends to burn hotter and with continuous air is rougher on the firepot. So thicker/heavier firepots are made to use it. When you buy coke it's industrial coke and not the lighter and less "intense" breeze.  Coke made from coal in your forge sometimes will float in a bucket of water. Industrial coke sinks. Industrial coke is better for some processes and worse for others. For example a lot of us forge with hand crank blowers, with industrial coke you will have to have another person in your shop just turning the blower continuously---industrial coke can and will go out while you are working a piece at your anvil.  Using coal burning to coke this is not a problem.  Good smithing coal will clump when burnt making it possible to have a "closed fire" which many people prefer for forge welding---especially when they are getting started. Coke does not do this you can only get an open fire with it. Etc and so on!

As an analogy think of diesel engines and gasoline engines. Why do we have two different types?  Diesel is better for some uses and gas is better for others---you can do a lot of tweaking to try to get one type to work for the other use case but it's a lot simpler to just use the one most suited for the job.  Very few "hobby" smiths need a "16 cylinder diesel engine" in their shop.

Now why do they sell charcoal when you can just use wood to get coals for cooking over? Why do they sell charcoal briquettes when you can just use lump charcoal? Why do some people want mesquite for BBQing and others want apple?  WHY? WHY? WHY?

The "usually" is to deal with petroleum coke, not used much in the USA but used a lot in China---not necessarily for forging; but for home heating.

Considering you are quibbling over something people have been doing all over the world in a hole in the ground for over 2000 years; perhaps you should drop blacksmithing and try machining, it's a process where fussiness is considered a plus.

If this is so much a problem for you; why have you not asked around and got a bucket of coal and a bucket of coke and dug a hole in the ground and figured it out for yourself! Get off the net and *DO* *SOMETHING*!

Forgive me for offending you with a simple question.  I will indeed move on. 

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You did not offend me with a simple question. You offended me by asking it again and again AFTER you were provided an answer and acting like it had not been answered.  My 3 rules for teaching new people is that they must 1 listen and follow directions, 2 they must be safe around other people with hot steel and 3 they must be safe around themselves with hot steel.  Listen is number 1.

I am sorry if treating you like you were treating me is unacceptable to you.

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