Efficient, Functional Charcoal Management in JABOD Forge

[Stahlmann]

Hi all, it's been a long time!

Over the last few months I've been waiting for my barbecue-frame forge cement to dry. We've only just recently gotten decent warm weather so I can set it in the sun to get it drying faster. But, I couldn't take the wait anymore and decided to use a wooden box frame that was given to me and turn it into a small JABOD style forge so that I can finally whack on some metal.

As you'll see in the attached pictures, this is a longer, narrow box that I've set a 1" pipe into (3ft long), filled with sand, and then surrounded the bowl area with firebrick. The top of the tuyere is set 3.5" below the top edge of the wood box, and the bottom of the tuyere is just a little more than an inch above the bottom brick of the fire bowl/rectangle. The crappy smokestack thing is just the charcoal starter pulling the smoke ever so slightly upward.

The last two days I spent a combined 14 hours or so desperately trying to figure out the secret to an effective charcoal fire with this arrangement in order to make a set of tongs. I tried different depths of charcoal, different placements of the bar stock, different airflow levels, different sources of airflow, everything....and in those 14 hours was only able to move the steel maybe 2" (sad, I know).

I'm using what I believe to be oak charcoal, mostly the Cowboy brand stuff. I alternated between a hair dryer and a small cheap fireplace bellows that will likely fall apart soon from over use. Both got the coals glowing and flames all happy, but didn't do much to the steel most of the time (which was mild steel by the way).

I tried the first day to mound the coals several inches above the tuyere, approx 4-5" as I've read in some past posts somewhere or over. With this arrangement, I was lucky to get the steel an extremely dull red that went black within a second. On day two, I made the fire much shallower as I saw someone doing in a Youtube video (all pictures are from day two shallow fire): with this arrangement it was hit or miss. Sometimes I would get no results while other times I could get the steel to orange in about five to ten minutes (one site said optimal forging temp for mild steel is yellow...?) I'm afraid, however, that at this shallow depth I might be oxidizing the steel, but it's the only way anything's happened yet. I also had better results having almost no charcoal on top of the steel, which I don't understand at all.

So, anyways, before I end up writing a book, I can't seem to figure out a simple charcoal fire. I've had extreme difficulty finding helpful resources, as a Google search specifying charcoal brings results almost entirely on how to start a coal fire.... I've tried light airflow, as I've been told charcoal needs almost no air (this wasn't effective at achieving forging temp), and I've tried heavier airflow from the hair dryer which was effective sometimes, others not so much.

Is there any more info I can give on the problem to inform your answers? Hopefully this will be a helpful resource for other people struggling with efficient charcoal fire maintenance.  

[Charles R. Stevens]

Single lung bellows don’t work so well, as you blow then pause. Blow then pause. You either need two in alternation or a double action. 

Break the charcoal up in smaller chunks. Say walnut size and about 2-3” above the tuyere and about that much fuel over that. Manage your air, two much is as detrimental to good heat with charcoal. 

I would consider rearranging things so the air blows in side ways to the trench. I think the air hitting the wall and moving up threw the fuel. 

I would consider ore rating things the other way, put the bricks up long way. If you put 2-3like that on each side (you have to either put a hole in there or pack mud around the tuyere) lay a brick sideways between the rows. Now you have a trench 4” wide, 8-12” long and 6” deep side ways, a single brick sideways each end gets the stock about the center of the fire. 

[Stahlmann]

Ah, I wondered if the on-off airflow of the bellows was a problem. The opening of the hairdryer is about 3" or so across, blowing into a 1" pipe; considering that, would you guess that placing the hairdryer on a low setting directly against the pipe as shown in the picture would be about the proper airflow (since about 2/3 of the actual air released will not be going down the pipe)?

 

So, with walnut sized charcoal, I need about 4-6" total above the tuyere and my metal sandwiched right at the midpoint, is that about right?

This leads me to another question I had about proper charcoal size. When breaking charcoal, lots of little chips go everywhere, should I burn these? I found that using these small bits and the breaking of coals already in the fire by stirring, I created a lot of charcoal dust/ash mix that I suspected was blocking full flow of air from the tuyere (which I concluded because the area of steel gaining heat was concentrated in a very small area). I'm not even sure if most of this accumulated dust was actual ash, as it was grainy and mostly black. Eventually I pulled all my big coals out and scooped out a bunch of this black dirt from the bottom, which was literally more material than the actual coals. Then I used my good coals to start a new fire (which still didn't work, but I gave it a shot)

How often would you recommend stirring the fire? Someone somewhere in a video I think said to regularly push coals downward deeper toward the fire, which I tried and just ended up breaking them down smaller and making more of that black dirt crap. 

[Stahlmann]

Charles Stevens:   I've taken a few minutes to ponder your suggestion for reorienting my forge and honestly I'm having difficulty picturing it. I think I see the logic of moving the tuyere to the side, but am not quite grasping the rest. Is it a general principle that the tuyere needs to be close to a wall-like structure to force the air upward, kind of like a bottom-blast forge? Does my current design mostly just heat a long section of bottom coals?

[Charles R. Stevens]

Well I have my theories as to why, and generally that’s about it. I looked at historical examples and experimented.

so what you have then would be an african/Asian style forge. A proven design. If you had a larger box or a table we could build a Viking era style forge. The reason for the 4”x8” Fire is that is a more efferent use of fuel.

I am on the road or I would sketch one for you

[Frosty]

Here's a Youtube video showing a Viking type sideblast forge being used to forge an iron bloom. I think there's another in this series of videos that show one being made by the youngsters who end up pumping the bellows a little later.

Once you see one you'll get to enjoy one of those head slapping moments they're so simple and effective. 

https://www.youtube.com/watch?v=J7nzmhFwGoM

Whew, that was close! I almost forgot to attach the link. I've remembered several things today I'm on a ROLL!! 

Frosty The Lucky.

[Charles R. Stevens]

Either just put it on top and let it break down or use a big knife, burn the fines. Hardwood charcoal contains more silica than soft wood (acual wood hardness not tree type) and produces more ash. Most of the ash being light is blown out of the fire. Typicaly with a hair dryer somthing like a cut up t ball or soft ball bat or a funnel works well then point the hair drier at the opening and move forward or back to get the heat you need. After you get the air right you will find the hot spot in the pile and that’s we’re the steel goes, as each forge has its own personality it may be an inch lower or higher in your forge than mine. That’s what’s nice about dirt, easy to modify. 

If you like manual air switch to a piece of 3/4” schedule 40 pipe and get one of these.

 

$10, plunges right in the tuyere, faster you pump hotter it gets.

[Stahlmann]

Thanks Charles and Frosty!

That link to different charcoal forge types was really helpful in understanding all the different effective designs across time and cultures. Also loved seeing a Viking style forge at work in that video turning super rough new iron into a bar. Would really love to try that out someday!

Hey Charles, I've got one of those plastic camping pumps stored back at home across the state, but aren't they alot like a single lung bellows? I know the blast would be much much longer at least, but don't they still pause in between plunging? Is that a big deal? If not, I'd love to use one as the hairdryer is noisy and kindof ruins the mood/feel of it all.

Oh, this morning I took your advice to the best of my understanding and turned my forge into more of a side blast Viking style. I decided to fill the box completely with dirt and set the pipe on a brick instead of drilling it through the box since,  with such a narrow box being close to the fire at that angle, the metal would certainly get hot enough to burn the box on contact. 

Anyways, the bricks are 9"x4.5", and so I made this the size of my forging space despite being slightly larger than ideal. The tuyere is actually 3/4", not 1" as I mistakenly said earlier, and is set the 1" above base brick. Despite the height, this thing feels pretty sturdy even without being mortared together. I may possibly cut a foot or so off the tuyere eventually. Looking forward to trying it out as is later today.

Any thoughts?

 

[Charles R. Stevens]

The one I showed is a double acting pump. Think  box belows

[Frosty]

This configuration forge will blow fire sideways on the bottom brick out the ends of the "trench" and burn the top of the box. . . Maybe probably, it's how it looks to me anyway.

My last side blast was more primitive but used a 12v DC,  Coleman Inflate all, mattress raft, etc. blower, a few feet of pipe and a block of wood for an anvil.  The yellow thing near the truck is the blower.

Frosty The Lucky.

[Charles R. Stevens]

 

[Charles R. Stevens]

Take your bricks, place one flat, place on on each 4” side, 2x8” side down, this will be an end and stick rest, now take your 4 bricks and stand them on end down each side. Hard fire brick carves ok with a cold chisel (rail spike works) so you can fit the tuyere tight.  

Last nights test firing has already led to changes, lol,

[robie1373]

frosty, I didn't know you were Chuck Norris! I heard you forge by simply telling the metal where to go. I also heard pritchel holes were invented when you accidentally poked your anvil in annoyance. 

[rockstar.esq]

See now I feel guilty because I thought he was Chuck Norris too...

[JHCC]

Frosty is what Chuck Norris wants to be when he grows up. 

[Frosty]

15 hours ago, JHCC said:

Frosty is what Chuck Norris wants to be when he grows up. 

Fat and lazy? 

Mr. Norris and Bruce Lee visited our dojo looking over and interviewing extras for a movie. Mr. Lee did a double take when he spoke to me and I got nothing but grief from the other club members for a while. The club owner Bill Ryusake played a villain on the TV show, "Kung Fu." Darned if Kwai Chang won the fight. Go figure.

But yeah, Chuck Norris and I look enough alike to be brothers were I in better shape I probably could've gotten a regular job as his double. Heck we even sound enough alike to be mistaken with a little back ground noise, say a crowd or traffic.

Frosty The Lucky.

[robie1373]

And then I learned that Frosty not only looks like Chuck Norris, but he knows him too. Smiling and shaking my head. 

Fun fact, I was an unofficial stunt double for the original Marlboro man in a white water rafting episode of Walker Texas Ranger. They spray painted my head silver and shot the scene from 3/4 of a mile away. I almost passed for him. I was 21 years old at the time. 

[Frosty]

I met him once, we didn't speak. I met and spoke to Clint Eastwood once in Craig, Alaska, he was on a fishing trip I was working up the road. He stepped out a door and  we almost collided on the sidewalk. He said "excuse me," I said, "pardon me." Does that count too? How about Dick VanDyke? We actually talked about horses for a couple minutes?

I'm getting giddy.

Frosty The Lucky.

 

[JHCC]

I sold a fair amount of furniture to James Gandolfini (Tony Soprano) back in my retail days, and we got pretty friendly. Apart from one rough patch when he was dealing with addiction and the pressures of sudden fame, he was a super-nice guy. 

If anyone’s interested, I can tell you a great story about Jim and me. 

[ThomasPowers]

Ali MacGraw once complemented my blacksmithing hat with horns on it at El Nido restaurant in Tesuque NM.    However I was more excited when Frank Borman gave my family a personal tour of the Manned Spaceflight Center in Houston.  (My Father was working for NASA 1962-1968 in the Washington DC "head office")...we had security badges with our photos and got to see a lot of backstage stuff.

[robie1373]

It's turning into an episode of "This is your life" in here