Building a more permanent charcoal JABOD

[Selph]

Hello again, everyone. I've been forging for almost two years now with my JABOD. I owe a lot to all of your help with that project and getting me started. Well, in the meantime we built a detatched garage with a separate room in the back with the idea that I could forge in there. Here's my current set up that I've been using up until now. I've been working outside and pulling it inside when finished working. That garage in the background is now living space. My father-in-law has had some serious health issues and moved in with us, and we needed space for him live which is what prompted the new garage/remodel.

 

Well, now that I'm ready to move this into a more permanent location and about to have a chimney installed for it, I'd like something that's a bit better constructed. Ideally out of steel. I'm a little concerned that over time the wood could become pretty flammable with pyroloysis, and I think the depth on this isn't quite what it should be. The bottom gets really warm after each forging session. I just wanted to run my idea past people who would know if I'm being crazy.

My idea was to weld up a table that looks like this:

Does that seem reasonable? My current table is something like 17 inches square, and I find myself wanting some space to pile up charcoal. I really like the ability to reform my bowl to whatever shape I need with the bentonite/sand mix I saw in the JABOD threads. My idea was that if I make that 12*24 section, I could reform it to be anything I need with all that space in there. Then I'd have that upper shelf which may only be an inch or so deep to hold charcoal/tongs/whatever while I'm working. If I'm doing something long like large knife (I've got an 8 and 5 year old), I could always split the tuyere and have two coming into the bowl. My tuyere is 1.5 inches in diameter (much bigger than I've seen recommended, but it works really well with my bellows), so the overall depth would be about 8 inches.

If you all want, I could take pictures while I build whatever I end up going with. I also need to decide between a side sucker/hood for the smoke/sparks. I feel like the hood might be better for catching the sparks, but I have no experience there. Thanks for all the help.

[George N. M.]

Selph, welcome back from 7500' in SE Wyoming.  Glad to have you again.

Is that a box bellows on the left side of your forge?  Single acting or double acting?  How do you like it?  Have you used a hand or electric blower and how does the box compare?

I'm no expert but I'd say your design should work.  There is no "right" way to do things, just whatever works for you.  I do agree that you should probably progress way from wood and to metal.  A JABOD is a great way to get started but it is an entry level tool.  I doubt many folk continue to use them as they progress in the craft.  Like you, they fabricate something better or buy one.

"By hammer and hand all arts do stand."

[Selph]

Yeah! It is a box bellows. I looked at a couple of videos online and just kind of made one off the cuff. I'm mostly a woodworker, so it was a pretty easy project. It's double acting and I love it. It's super quiet in use. You just hear the wooden valves click-clacking and the whoosh of the fire. I've forge welded with it no problem. More than enough air. I've honestly never used anything else at home. When I first started I took a class with someone else and they had an electric blower with coal, and that was nice too. I kind of like having something to do while heating up the steel. Keeps my attention on the task at hand. I could probably take the top off and take some pictures if someone wanted me to.

And yes, that was kind of the impression I got. That more or less anything can work, it just depends on your personal style and how you do things. I'm not changing a ton from how I had my forge before, but just making a few tweaks here and there. I do like being able to reform my bowl if I want. But I want to remove as much fire risk from forging inside as I can.

[Frosty]

Glad to see you again Selph. It has been a while but I remember your build and my original question still stands. I don't understand why you partitioned the box. It looks to me like a LOT of room to pile fuel or lay stock while you work.

Building it out of steel is a good idea, just don't get carried away with thickness, I've built some pretty structurally demanding things from 14ga. My long retired beginner too large coal forge is a 36" x 48" table with 2x2" angle flange up rim, supported at the corners with spreaders and hips. The ONLY reinforcements are two 1"x1" angle iron across the 36" direction under the pan. The forge table is covered in a layer of salvaged firebrick, the duck's nest is rammed clayey soil. The weight on the table has to be in excess of 300lbs. not counting, fuel, projects and tools. I was dumping 2-3 5gal buckets full on it at a time. Unfortunately it was really poor coal and I'm too old and decrepit to collect the good stuff at the decommissioned mine.

I'm not suggesting that as your forge build, it's just an example of how strong steel sheet is. 

As a build thought, that 12" partition would be a natural place to put a bosh. 

Frosty The Lucky.

[Selph]

I'm amazed you would remember those posts.

On the partition, are you asking why I'm doing it to this forge? You're probably right that it's too much room.  I didn't want to make it too small and regret it, but being too big isn't ideal either. The current box I have is 20 inches wide, but only 13-14 of it is usable past those fire bricks. The newer iteration I was planning on having less dead space and shortening the tuyere a bit. I was thinking a 24x24 footprint wasn't too bad. Of course, the bellows will still stick off to the side, and they're 33 inches deep, so I'll have to take that into account too.

I had to look up the bosh, that's a pretty good idea. I could drop the width down to 18 inches and add one of those. That's four extra inches to hopefully make it so I stop knocking the charcoal off the table or having the fire spread to the charcoal that's waiting in reserve. It's possible that the better solution would be to just make my own charcoal. The charcoal I'm using comes in pretty large chunks and it's hard to get it stacked up well and under control. That's why I feel like I need more space for the charcoal and whatever else. If the charcoal were better sized, I think I could just keep a scoop nearby for topping off the fire. For steel, I had been thinking of using 1/8, but maybe I could just use 3/32 or something.

I appreciate all the feedback!

[Charles R. Stevens]

A classic side blast is a box about 12” deep and 30” across filled with fly ash and clinker. Sided with a 30” square table tiled with brick. The tuyere sticking in so as to center the fire. 
this is of corse a coal fire. Charcoal really needs a wall or trench as one can’t bank charcoal like you do coal. 

[Frosty]

I remember good looking builds and your box bellows is down right attractive. I'm not surprised you don't remember my original question nor the discussion. The only reason I could come up with for that large a section and tuyere in open air was for cooling. 

You know, you could make the fuel tray fit over the open section and use that space. Vents in the bottom on one side and the top on the other would provide air to help keep the tuyere cool. IF that was a thought. 

I'd probably make my own bosh, marine through hull fittings are easily available though it wouldn't be tough to scratch make one. What I'd do WAY differently that a traditional bosh is make the terminal nozzle from Kastolite 30 or similar castable refractory and change them out if, when they burnt past good performance. That's mostly just thought food though.

1/8" is 11 ga. heavier than modern pickup bumpers or car ramps. I used 14 ga because I had it, not because I thought it was necessary, 16ga for a box the size you propose would be lots of overkill strength wise, especially if you weld the partition. 

When I was considering something like a JASBOD (Just A Steel Box Of Dirt) I was salvaging various steel boxes, electrical panels fit the bill more often than any other particular type. That was before I made my first successful propane forge and had delusions I could use coal here. The forge I was using at the time was about 3 buckets of dampish dirt on an old kitchen table in the yard and a "Coleman Inflatall," air Mattress inflater for the blast.

I'm in danger of going off on a long old memory ramble. Later.

Frosty The Lucky.

 

[Selph]

Charles, thanks for the input! Right now I'm working with more of a trench, I've been thinking about using more fire bricks this time to create a more confined and defined space for the charcoal. I think that might help me be a bit more efficient with my fuel usage. If nothing else though, I know the trench-style I've been using has been working for me for a while, so if the more boxed in space doesn't pan out, I know it'll still work.

Frosty, I really appreciate the compliment on the box bellows. I made them fairly quickly, but I've been woodworking longer than blacksmithing and I did want them to look nice. Also, I'm a bit embarrassed to admit it, but I'm not sure I ever understood what you meant until just now. I apologize for being dense on this. You're talking about that big air gap between the bellows and the body of the forge itself, right? The only reason it's there is because I didn't want to cut the pipe for the tuyere and regret cutting it. That and paranoia about protecting the bellows. I could make that substantially smaller, you're right. How small? I'm not exactly sure, to be honest. It's at least a foot right now, as the tuyere is 18 inches. Maybe I could drop it to a 6 inch gap? I assume I need a bit of air in there to keep the tuyere cool, but maybe less than the 6 inches I'm imagining right now. It's getting cool air run through it each time I use the bellows.

For the bosh, I've now found two different definitions online. The first one I saw was essentially a slack tub attached to the forge body. That's honestly a no brainer and I don't know why I haven't done it. The second definition I've seen out there is for a water cooled tuyere essentially. For that, I found some instructions on the calsmith website (I'm not sure I can post links, so I'm avoiding that), and I'm guessing that's what you're talking about. I could do that to shorten the gap there to just a couple of inches probably. Basically, bellows, then 2-3 inches of water tank, then make the steel end of the tuyere mate to a Kastolite 30 or something tuyere/tunnel thing that actually feeds the fire itself. This might keep the steel from being used up and I can replace that cast refractory segment as needed.

That sounds really interesting and fun to try and make.

[Selph]

Oh, another question is: Side draft hood or a standard hood for a side-blast charcoal forge like this? I was thinking standard would do better with all the sparks, but I've never used either of them or even seen them in real life.

Thanks again for the feedback, everyone.

[Charles R. Stevens]

Side draft. They seem to work better and get the hood out of your way when working on larger projects. 

[ThomasPowers]

Side Draft, drying your charcoal before adding it to the pot and lower blast helps with the sparking. (And also don't use partially charred charcoal, we see a lot of that in Mesquite as they don't want to lose the "flavor" and so the resin inclusions make a LOT of sparks---but you can buy it cheap in 40# sacks from Mexico...)

[Charles R. Stevens]

A retort and softwood scraps work well for charcoal Harder woods (like oak). Contain more silica, and thus more ash than softer woods like fir, alder, cottonwood etc. 

[Selph]

A charcoal retort or something is in my future probably. We live on a very wooded lot with almost exclusively hardwoods and just downed limbs and dead trees would provide me with all the charcoal I would ever need. The issue being I've got a project list a mile long and my wife doesn't feel like "charcoal retort" gets me closer to finishing stuff. Most of it is red oak, white oak, and cherry.

Are there any versions that are decently efficient without taking too long to fabricate? While I'm welding together the new forge, I could probably sneak something else in too.

[Charles R. Stevens]

55 gallon drums don’t have a long life but a clamp top with the gasket replaced with wood stove door gasket can be configured in a cupple of ways that work. One just has a few holes around the bottom rim that you block with dirt and a hole in the top you block. 
load it about 1/3 and start a fire, load and wait for it to get lit, put the lid on and wait till the smoke clears and seal it up. 
the other style sits in its side and you build a fire under it. As they usually use a vent pipe to burn the gasses off they smoke less. 

Either way you burn about a third of the wood to fuel it. 

[Fly]

Charles you amaze me with all the knowledge you have acquired. You need to write a book for sure. Your knowledge goes 

back so far,I hope it,s not lost after fellows as you past on. 
            
Fly