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I have a small portable forge at home (rescued from my grandparent's farm) with a hand crank blower. I've been working successfully with hardwood charcoal, but have been contemplating the switch to coal.

How long would, say, a 50# bag of coal last me compared to a bag of charcoal?

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Coal and charcoal have pretty close BTU's per weight so compare it on that basis with the caveat that coal doesn't burn as fast when you stop putting air to it as charcoal does.

Since you don't tell us if you are using a 8 pound bag, 10 pound bag, 40 pound bag, etc of charcoal it's hard to give a value.

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I imagine that a 40# bag of coal would take up quite a bit of space. Currently, I buy 8# bags of charcoal, and dump them into a wheeled garbage can that I found in the ditch.

And since charcoal is less dense than coal, it follows there would appear to be "more" charcoal for the same weight, but it burns faster.

The thing is, I'm wondering about the volumetric qualities. If I fill a five-gallon bucket with coal, how much longer will it last than the same bucket-full of charcoal?

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Do it on a *weight* basis.

40# sacks are generally the cheapest way to buy charcoal; though you have to find a place that has them. Some restaurant supply places that cater to oldstyle BBQ places may have them and it was the way we would buy 300 pounds of charcoal to do a bloomery smelt with---that was from the charcoal "factory" in PA

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A bucket/can of coal will far outlast the same volume of charcoal, for identical uses

Then you also have to take into account other variables,

How fast you are cranking your handle

Is there any wind involved if you use the forge outside,

The types of lengths of heat you will be using (forging/welding/twisting)

Size and sections of materials you are using

Type of materials you are forging,

and more importantly YOUR fire management skills

Try it for yourself and make your own judgement, enjoy

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When you say "small portable forge" I think rivet forge. I've burned both coal and charcoal in such a beast. If you put lining in the pan and control the size of the fire there can be little difference by weight in coal and charcoal. if you haven't lined the pan, or don't keep your fire confined you'll likely find you use more charcoal by weight than coal.
But there are a lot a variables in this particular equation so you may find results all over the place in practice.

Coal is about 5 to 10 X as dense as charcoal (depending on method of making, species etc), so you expect to use 5 to 10 X the volume of charcoal as coal.

ron

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I've been told in the past on this site that 100 pounds of coal with give you approximately 40 hours of forging. Naturally give or take a few hours and 50 pounds should be around 20 hours or so of forge time. I've never used charcoal myself but from what I can tell, the above holds true. Hope that helps.

Kevin

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when I swithced from charcoal to coal I noticed a huge diffrence 30lbs of coal last all weekend for me

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when I run full out a 5 gallon bucket last me a 8 hour day you will use 3 to4 times the amount of charcoal to coal by volume. with the price of hard wood charcoal I would not switch back myself. The forging with charcoal has its merits.

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OTOH one of my coal forges burns coal at several time the rate of my other coal forge so that estimate of duration my be off by a factor of 2 or more.

(Of course the previous owner of my big forge burned up a railroad rail in it---as in put in one piece and take out two pieces!)

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Now, here's an interesting tidbit.

Every so often, when I clean out the ash from my forge, I find small, hard, rocky objects down by the grate. They look like clinker: they're light, and kind of glassy with lots of air pockets.

Now, I burn charcoal, and to my knowledge, charcoal doesn't produce clinker. Could I be destroying the cement fireclay in my rivet forge, now that it's being used after 50 years of flower-pot duty?

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