Question about charcoal forges

[123samic]

Hi

I'm thinking about building a charcoal forge and was wondering if the basic design was any different from a coal forge

 

thanks,

Sam

[tarheelsteel75]

Hey Burlington area of NC here.....I built a forge like some of the designs I have seen on here and youtube and have so far only used charcoal for fuel.  I am still kinda new at this but I can't see where there would be any differences.

[Frosty]

Take a good read through the forges section here, there are  more designs for coal/charcoal/etc. forges than a boy could want. Pictures, drawings, plans, etc. from store bought to home made to improvised, they're all covered.

 

Frosty The Lucky.

[Harris Snyder]

I'll share my experience with using charcoal, which I did for roughly my first year of forging

 

1) Volume of air is more important than velocity. Charcoal is very light and high velocity air will blow it away from the tuyere. Try to blow air in slowly but through a larger pipe. Hand crank blower would be ideal in my opinion, but electric is fine if you can find a good one with more volume than pressure.

 

2) "Charcoal needs less air than coal". Quoted because I see it everywhere, not because I've ever used coal (I haven't). What this means, though, is that charcoal fires don't eat all the oxygen as readily as coal fires, and so they should be pretty deep to prevent excessive oxidation and scaling of the metal. In my opinion this is the biggest thing that "improvised" forge designs fail at. I used improvised forges, including a pile of fire bricks on the driveway, with a hairdryer blowing air in. When building your forge, do have some sort of fire pot. The exact dimensions of it are up for debate (both in terms of how important they are and your particular application), but I do highly recommend some sort of fire pot with air coming in at the bottom. I have a thread just a few entries down where I was asking about dimensions specifically for a forge welding forge, and the numbers being suggested were pretty deep. A 10 " deep fire pot might not be the most practical for everyday forging, but you'll be much happier having SOME sort of firepot to build a stack of charcoal in than just a flat bottom with a pipe entering it.

 

3) It burns pretty quickly.

 

That's basically it. I'm using gas now, I made the switch quite recently. I liked forging with charcoal more to be honest, but gas helps me get more work done because I don't have to feed or tend to the fire. I don't ever intend to use coal, I study physics and environmental science and that sh** is so bad, I can't bring myself to burn it. I'm sure its a great fuel to work with for smithing, but I'm not gonna go there.

[Dan C]

This forum is truly an astounding wealth of information if you just take the time to look.  I stumbled on this one while trying to understand why I've been accidentally burning up more pieces I'm working on.

 

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[123samic]

Thanks Harris would a break drum work as a firepot?

[Harris Snyder]

I've never used a brake drum forge. I know lots of guys get them working, and I know that often they're a first forge project for people. However I've noticed that the upside down pyramid shape of fire pot (or a more cone like shape) is more common in commercial fire pots and my experiments seem to suggest that there's good reason for that. Try lining the bottom corners of the brake drum with fire clay to make it a little more bowl like or cone like instead of being a cylindrical shape (if you know what I'm trying to say). I'd say look at commercial fire pots and try to make the inside shape of the brake drum match those. My guess is you'll have a better end result than if you just use the brake drum on it's own.

 

I'd also suggest having at least a little bit of "table" around the fire pot  That way you can put fire bricks around it if you need a deeper fire, and it'll be easier to make a proper pile of charcoal so that you have the right combination of heat and atmosphere (i.e. not unuseably oxidizing).

 

Lots of people forge and do better work than I can do with just a brake drum and some coal, so yes, it will work. The above just lists my suggestions to turn a brake drum into an awesome forge that you might never outgrow.

[ThomasPowers]

So what do you want to forge?  The Tim lively washtub & adobe forge is designed for charcoal and knives

 

Now as to air: I started with a charcoal forge about 32 years ago and have used them for historical recreation (coal didn't come into blacksmithing use until the high/late middle ages, Gies & Gies "Cathedral forge and waterwheel")  What most people don't consider is that charcoal tends to be MUCH larger chunks than coal, this leaves less surface area and much large voids for air to travel through making it easy to get an oxidizing fire going ESPECIALLY with an electric blower.  In a bloomery Rehder, "Mastery and Uses of Fire in Antiquity", says that the reducing zone is about 12-13 times the mean diameter of the fuel---just think 1: cube charcoal needs a fire over a foot deep to get it reducing if you are pushing air through it in a bloomery!  Bellows or hand crank allows you tom be very gentle with the air and keep a reducing fire in a reasonable size.

 

All of a charcoal fire tends to burn meaning you go through a lot of wasted fuel as stuff off to the side will burn up while not contributing to heating your workpiece.  So I tend to narrow and raise my coal firepot with fire bricks to get a deeper yet narrower fire with less charcoal.

 

And finally: FOLKS PLEASE DON'T POST IF YOU DON'T KNOW. There are enough weirdos here with decades of odd experiences that someone will probably turn up who can answer a question with  experience rather than guesses (even for such off topic things as getting slapped by a birch tree when you kissed it!)  And PLEASE DO POST IF YOU HAVE EXPERIENCE AND RESEARCH ON A TOPIC

[Harris Snyder]

And finally: FOLKS PLEASE DON'T POST IF YOU DON'T KNOW. There are enough weirdos here with decades of odd experiences that someone will probably turn up who can answer a question with  experience rather than guesses (even for suck off topic things as getting slapped by a birch tree when you kissed it!)  And PLEASE DO POST IF YOU HAVE EXPERIENCE AND RESEARCH ON A TOPIC

 

Are you referring to me? My suggestions are in line with yours, so I'm not sure what the problem is there. I have lots of experience with makeshift charcoal forges eating fuel and oxidizing my steel, lol. I have less experience with proper fire pots, but my last charcoal forge was modeled after a commercial (centaur forge) fire pot, and it worked beautifully. I just found that it still was easy to oxidize (hence my other thread asking specifically about a forge for welding)... Anyways...

[123samic]

so in terms of a forge will somthing like this work, with a hand crank and fireclay to shape the firepot

 

 

[Harris Snyder]

Looks like a great forge to me! Keep a couple fire bricks on hand in case you need to stack them up around to deepen the fire pot.

[ThomasPowers]

I would infill the sides of that firepot and add a row of fire brick along the top to deepen it.  More of a U shaped cross section.