WillyP

Charcoal Question

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Hi all,

I've got a question on the air requirement for burning charcoal.

I've built myself a small forge out of an old temporary spare 'dummy' rim. I've lined it and placed an air tube in the bottom by cutting a 1-1/8" hole through the rim. I left this tube long (like about a foot outside the rim) for now until I get an idea of what the thing is going to need at the finish.

I tried this little guy for about 10 mins tonight with about a half a tomato juice can full of charcoal that I "made" by scooping a couple small scoops of hot coals out of my woodstove and putting them into the tomato juice can and covering them with a piece of sheet steel. I did that a couple weeks ago when it was still cold enough to burn a fire in my woodstove.

I used a hairdryer for the air source - tried a bit on high and a bit on low - of course I need something in between...

So the charcoal was not really the best but it did burn pretty hot, I stuck a piece of 1/2" mat'l (the straight end that used to be a tire iron) in the coals and in about 7 or 8 mins a section about 4" was dull orange - from dead cold - so I was kind of impressed.


I had thought of using a small hand pumped bellows. The tube would be perfect for it, and it would give me pretty good control over the air. This is a small forge - the fire pot is only about 11' long and because the tuyere is a pipe with holes it's long and narrow - an inch or two wide.

Here's the questions: 1. Will the charcoal die out if I get to working away from the fire too long without pumping air?

2. Since I just had a handfull of charcoal tonight the fire was long and skinny, but once I can get a better load of charcoal in there will the hot coals become much wider? I've never used solid fuel.

3. If using more charcoal makes the hot coal bed larger, will a hand pumped bellows be enough?

That's the questions that are on my mind for now, any help or suggestions or critisisms (as long as they are constructive) are appreciated!

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Charcoal is great for forging with, especially with bellows. I use a 'primitive' set up for teaching and public demos, the forge and bellows are based on examples from the first millenium BC in Europe.

My forge bed is larger than yours (about 20x15" for the teaching hearthes) and a single bellow with approx 1 cubic foot of air blown through a 1 1/4" diam tube will raise a 1" bar to welding heat. For higher heats you just need to up the rate of pumping and keep a good head of charcoal above the metal for insulation.

One great thing charcoal has over other forge fuels is that it doesn't lose heat too fast without applied air, so its not too strenuous keeping good heats in your work. When the air is 'switched off' then you are left with a nice little BBQ for your tea ;) Obviously the hot coals spread outwards as the day progresses, but if you keep raking them in and feed fresh fuel in from the sides then the spread of radiant heat isn't too bad.

best thing, as with all tools, is to play with your set up once you have got a feel for forging with charcoal. tweak the size of the fuel, the air inlet size, type and capacity of bellows, method of uniting the bellows and tuyere, method of pumping the bellows for different types of work, etc..

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1. Will the charcoal die out if I get to working away from the fire too long without pumping air?


No. It will often burn unattended until there are only ashes left.

2. Since I just had a handfull of charcoal tonight the fire was long and skinny, but once I can get a better load of charcoal in there will the hot coals become much wider? I've never used solid fuel.


You need a deep fire, with as much fuel over your piece as you have under it. When you have a shallow fire, you are working against yourself... need more heat, give it more air, burn more fuel, so on and so forth...
A deep fire doesn't require a violent blast of air, particularly with charcoal. A firm but steady blast will build heat in the core of a deep fire, and the heat in your work will come up without trying to force it.

3. If using more charcoal makes the hot coal bed larger, will a hand pumped bellows be enough?


I often use a bellows with charcoal, and it is more than enough. Have welded with it, and have burned steel up when I wasn't paying attention.

I honestly believe that there is a point where there can be too much air going into charcoal. But this is in ratio to the amount of fuel you have going. I like the bellows because it kinda "breathes" into the fire instead of blasting it.

Hope this helps,

Don

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Hand pump bellows of one sort or another have been used with charcoal forges for the last 2000 years. I don't expect they will stop working any time soon.

To be efficient you will need a much larger stack of fuel. When I use charcoal in a coal forge I place a couple of firebricks in it on edge to make a narrower but deeper firepot. It requires less air than coal though and a bellows (or hand crank blower) is a superior method to provide it than an electric blower in my experience. In particular the double lunged bellows or the chinese box bellows work well with a forge and can be built at home fairly simply and cheaply.

And as was mentioned: with charcoal you can cook over your forge!

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Ok! Thanks for the input Fella's! I'm going to give this a shot and see if I can fix something up that I can pump with a foot pedal. I wish I still had my Pake's (Grampa's) old hand bellows. it would be perfect for this operation.

Here's another question:

I've made the tuyere in similar fashion as the Lively Washbucket Forge. Tube wall is approx .100". How long can I expect this tube to last before it burns out. There is a small layer of refractory cement on top of the tube; I stuck golf tees in the holes to keep them open while the cement cured; but it's so thin that sooner or later I am sure it will break down and the steel of the tube will be exposed to heat.

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1" black iron would probably last you a really long time, but don't sweat using what you have.

A forge like that is going to need occasional maintenance, so run it 'til you have problems then replace it.

By the way, keep some of your refractory handy to fill cracks with and don't sweat them either. Actually, you can probably fill the cracks with ash paste and be fine.

A Lively rig is not supposed to be "hi-tech", so don't over think it. Just be safe and make some heat.

Don

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I have used hand crank blowers, bellows and electric fans, and prefer electric hands down. U need a damper to regulate the air. Old airconditioners and clothes dryers are good sources of blowers. Too much air is better than not enough as u can choke it back if needed.

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I come from the other side of the country to Duckpond and like the reverse. I used a blower for a while and kept burning projects and lots of extra fuel. I use coal mainly and charcoal when I get it and find that a hand cranker is just about perfect for me. The fire dies down a bit while you are working on the anvil but it soon comes back up and heats the metal slowly and uniformly. After saying that, I am a bit lazy and like to forge at a slow steady pace and take my time, its kind of a zen like state.

In other words, pick your poison and try all options if you can.

Plans for a box bellows can be found here.

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I'm really kind of impressed that you made your own charcoal. You shouldn't have any problems making a hand pump bellows, plans abound. I favor a 2 chamber bellows myself.

Joe

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