james austin

Another JABOD forge build

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I've been working for the past month or so on building myself a small forge.  Basically I was looking for the minimum size and cost that would get me pounding metal.  I have been reading the various JABOD threads since the summer trying to decide if it was the right thing or not, but i decided to just go for it.  Built the box out of some scrap 2x6 that I had around.  I cut a single huge dovetail in each corner to hold it all together.

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I slaked some kitty litter and mixed in some sand, and beat that in as a floor, then started arranging bricks to make the firepot.  I will admit that I got a bit confused between the different variations of the jabod, and probably didn't need to go this far, and the thing ways a ton.  As I got going on this I decide that loose fill would probably be easier to manage, and I could empty it out when I need to move the thing (i've got to put it away when not in use). Anyway, after filling the thing up it looks a bit like:

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Once I got here I couldn't just stop, so after a quick break to make dinner for the family I fired it up. Seems to burn pretty good:

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I think I made the fire pot too deep, and too short.  I think I will probably turn the whole thing around in the box, make it shallower and maybe use the two wall design rather than the viking style here.  I had a pretty tough time getting metal into the coals rather than just on top of them.  again I think this was my confusion due to reading many threads on JABOD forges, and just combining a few to many ideas in one place.  I'm also probably just about at the edge of how small a box can be used with these; this is 12x16 inches interior, and I expect 16x16 inches might be better.  I think it should be pretty effecient thought.  I spent just over an hour, and only burned a few handfuls of charcoal, maybe a quart or a bit more at most. 

Thanks to Charles Stevens for showing the way with these.  I spent a lot of time thinking I needed the 'right' equipment like an iron forge table, and blowers and all that, and put off getting started on my own. So this seeing these was a big push forward to just get it done.  The teacher I had for the fundamentals class I took also suggested using a sledge as an alternative anvil, so I scrounged one up at the tool consignment.  If not for this sort of encouragement, I'd still be sitting around waiting for a way to make my tools.  Instead I'll be happily bashing away in my back yard.

Here's a shot of the anvil station:

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Rats.  And I'm supposed to be a millennial too!  Looks like they are jpg, but probably much to large, almost 3 Mb :blink:  Lets see if this works...

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Do you see a picture?  The others I posted show up for me, so I cant quite tell.  Thanks for the heads up Glenn!

also is there any way to edit the first post?  don't want to clutter things up with a million photo links.

 

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I think I got this working now.  just paste the link into the text box, and the photo shows up?  Double click on image to resize to 500?  shows up in another browser, where the previous ones did not.  Thanks for putting up with another newbie!

no photo attached

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Perhaps now I've got this working?  It shows up as an attachment on the post which is more than before.

Is there a consensus on how deep the firepot (is that the right term?) should be?  It's probably a half brick deep right now, and I think I read that it should be more like the thickness of a brick.

Thanks

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Yes the consensus is that the firepot should be deep enough to support YOUR work and YOUR fuel and YOUR air supply.  Charcoal does better with a deeper (or taller) fire than coal or coke does as the generally larger pieces don't consume all the O2 in the blast without more of it to travel through.

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Looks like you have a 2x4 frame, that’s about 1/2 as deep as you need. Not unless you sculpt a mound. 

2” minimum of insulation (clay, Adobe, brick etc) below the fire (wood ignites at about 600f ) and generally you need 3-4” from the top the tuyere to the hearth, with another 3-4” of fuel from on top of the hearth ( with of your hand or so). A little experimentation will show you how high the fire ball is with your air flow. 

As to pushing the stock threw the heart of the fire; large chunks of charcoal makes it worse. Make a set of fire tools, a rake, pick and shovel will make life easier and the hook and shovel make things easer.

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Thanks Thomas and Charles.

The frame is 2x6, which is probably still on the edge of too small; I did get pretty close to two inches of adobe in the bottom layer.  I am still planning on building up small walls on top of the hearth with a couple of bricks.  I'll try smaller bits of charcoal next time.  I think my main problem may have been not enough charcoal over the hearth.  I got pretty good heat if I angled the metal down a bit into the hearth, but I understand that isn't great practice. 

Sounds like fire tools will be a good project to practice on, and get some experience with the fire.

Thanks again

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The heart of the fire will radiate at the same heat colors as the hot steel (don’t look directly into the fires heart to often as you can develop glass blowers cataracts. 

Model in mind that a white heat may burn carbon steels, yellow is plenty hot. It may take longer but buy letting the steel soak it will heat threw. The subsequent heats are faster as the steel is already hot. We all get in a rush.

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When I rebuild my jabod I'm planning on only using a two inch deep trench with the tuyere an inch below the table with an inch underneath it for ash etc and bricks on either side of the trench to hold the fuel. If I need to raise the stock farther above the tuyere due to excessive scaling I have some split hard firebrick to use on the short Sides of the trench to raise the stock up the thickness of a split brick until I get it the right height.  I'll let you know how it works. I hope to have it done by the weekend but that depends on the landlord and the weather. 

Pnut

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I'll be curious how that goes pnut.  I had an hour last night, so I dug out the bricks started over.  Thomas' comment about needing a fire to support MY work was kind of a face palm moment for me.  I realized that everything I want to make is long and skinny, and I had built a small square forge.  I converted to more of a trench style as well, only about two inches wide but 6-7" long.  I'm hoping this will keep fuel use down still, but give me a longer hot spot in the fire.  No pictures at the moment as my basement is a dark hole in the ground, but I'm hoping to fire it up this weekend. 

On 1/14/2020 at 2:00 PM, Charles R. Stevens said:

We all get in a rush.

So true.  I always struggle with this, and steel always seems to go so slowly. 

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With charcoal your only going to get a 6” long hotspot unless you go to a multi tuyere design. But unless your doing really long scrolls of heat treating long blade.

I myself go with 4” wide, but let’s see what 2” dose

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I'm not sure such a narrow trench will work, but It seemed worth a try. I left most of the dirt fill pretty loose at the moment expecting to want to rearrange the fire as I learn what I'm doing, and if this is a mess it'll be pretty easy to move it again.  Your use of the dry kitty litter gave me the idea.  The version above the firebox was really only 4 inches long, and only really seemed to heat about 2 -3 inches of steel at a time.  One of the things I promised myself with this project is that I won't try to get everything right the first time, but rather try to do something, and improve on it as I go.  I'm still hoping to get this version lit on Saturday morning before we get snow.

On a related note, how do these forges survive outside in the weather?  at the moment i'm keeping it inside, but the weight adds up quickly, and i'm not really thrilled about carrying this around. Should I make a cover? would just a bit of tarp work to keep the worst of the rain or snow? Just stop worrying , and learn to love the bomb?

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