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I Forge Iron

Coal..a few questions


Gromgor

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So, I've been using charcoal for a while mostly because I never found a coal supplier in the area, until now. 

 

So I want to try out some coal and see how it compares. Which I like better, etc.

 

So first question: Are there any things I need to know about coal that makes it function differently than charcoal? I know it smokes a lot more, but are there any specific properties I need to be aware of?

 

Do I need to soak it in water? Does it need to be a certain size? I've read on this site that coal sticks to itself. I'm assuming it gets tacky when heated and bonds. Is this accurate and if so, how does that affect your work?

 

 

 

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One big advantage of coal is lower ambient heat than charcoal.  Coal is best added to the edges of the fire in a damp or even wet state... as it heats and cokes it will form large clods that sometimes have to be broken up a little... though a big one to roof the fire ball is useful.  Especially if it has lots of dust, the moisture creates slurry and the coal cokes into nice chunks instead of just blowing out the chimney!  Coal seems to need a bit more air than charcoal.  I am kinda tight and usually keep a small hot fireball by sprinkling the edges now and then when the fire threatens to expand too much.  When working large hunks of metal, though, one needs a larger, deeper and hotter fireball.  It is also wasteful to keep a too small fire for the work at hand... wastes coal, time and energy!

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Not all coal is created equal. Soft bituminous coal is typically good for forging. Hard anthracite coal not so much, but it will work. The soft coal lights easier and doesn't require that you run air all the time. Hard coal has a tendency to go out if you just shut down the blower between heats. It also takes me quite a while to get the forge up and running compared to soft coal. I usually need a pretty good sized fire out of charcoal and wood to cook the hard coal to the point it wants to burn on it's own.

 

I have a small quantity of soft coal I got for use with my little hand cranked forge for demos. I'm still working my way thru 4 55 gallon drums of free anthracite coal that I use in my big forge with the electric blower. I have it set up so when I damp down the air blast I still have a medium flow of air to keep the fire going.

 

Also some coal is "dirtier" than others. My soft coal is very clean and leaves almost no clinker. My hard coal is moderately dirty as it was shoveled up out of an old coal bunker in a basement so they could empty out the house. The coal itself makes a moderate level of clinker, but all the dirt and crud that got mixed in off the bottom of the bunker can increase that if you are working out of one of the last buckets we filled. Once I use up the last of this I'll just be buying soft coal from now on.

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Be aware that coal != Good Smithing Coal.  If it's a new source and you don't have endorsements from other smiths don't go all out and buy a ton before trying it.

 

Learn to manage your breeze so that the next start up isn't too smoky and as mentioned a shallow fire can be bad economy!

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DSW you can blend the hard and soft coal. Just find what mix works best and your good to go. 

 

Wetting the coal is not the same as pouring on water. All you need is a small mop dipped in water to dab on the edges of the fire to slow it down and keep it from spreading. You can keep coal dust in a bucket of water and grab a hand full of black mud and place it on the edge of the fire.

 

Smoke can be controlled by opening a hole in the top of the fire to create a volcano. The fire ignites and burns the smoke.

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Thanks Glen. I need to pick up some more of the soft stuff next chance I get. I'm saving the soft stuff I have right now for the small forge for demos for scouts and so on at the moment.

 

It's not really all that bad once I get the fire up and running. Starting the fire is the biggest issue and I've "cheated" and used some of the soft coal several times. I just have to be more aware to keep the fire clean and not let it burn down too much while I'm working. If nothing else it's teaching me good fire management practices.

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DSW, cheated?

 

Build a fire that would make a boy scout proud, Then add solid fuel over the fire and coals. This will generate the heat needed to start the coal burning. Once that fuel catches, add more fuel and get a fire ball going and be happy.

 

I have never seen the price of an item on a demo table cost more just because you used only 2 sheets of newspaper to get the fire started. I have never seen the item cost more just because you used 2 heats instead of 5 to make the thing. 

 

The metal does not care HOW you got the fire started. The metal does NOT care what type fuel you use. The metal just wants to get up to forging heat and to get moved around a bit to become something else. (grin)

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Only bituminous coal cokes [good] and you want it in slack size. about the size of a really, REALLY big peanut. (like, REALLY big)

 

To start my fire I use coal dust to coal about the side of ping pong balls. 

 

If you purchase lump coal, you just hit it with a hammer to break it down into smaller pieces. 

 

Once the fire is going I have added lumps the size of bricks and larger. Let them warm up and hit them with the shovel to break them up. They fracture in layers and the layers then fracture into pieces.

 

If you have coal that has been screened to a certain uniform size, all the better. It can be the size of pea gravel, up to the size of golf balls to walnuts which seems to be preferred. It is a matter of one lump or two, or one shovel or two, your choice.

 

Keep in mind that different parts of the country have different types of coal. I have used coal that is mostly shale that will barely burn, anthracite coal, and several coals in between. We are fortunate to have good coal in this area.

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I mix anthracite with homemade charcoal.  My air grate is made of 1/4" square so more designed for coal than charcoal.  The anthracite seems to help with the air flow to keep the charcoal from turning into a small volcano, I still pile the charcoal higher than you would coal or coke.  You can't make a beehive with it, or at least I haven't been able to.

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