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Advice on firebrick


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Hello, 

This is my first post on iforgeiron. I've learned a lot from Charles R. Stevens posts and if you see this post, thanks for sharing your knowledge . I have a plenty of hard fire brick that I bought from a reuse store for $5 a box. I bought them years ago because it was a good deal. I'm now interested in building a forge to form a cant hook for my wood working materials.  I'm just wondering what purpose the firebrick would serve in a ground forge or jabod.  I've read that the hard bricks are conductive to heat and don't insulate like soft brick. Anyway, just wondering if and how I should utilize these bricks to make a more refined or durable forge. Should I coat them in a refractory material? Just general newb questions having never forged a thing. Also, is using a dry bentonite cat litter better than wet clay or soil?  Thanks for any advice.

Dan

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Hello George, thank you. I'm in Cincinnati, Ohio in mud and slush and would gladly trade places! 

I was thinking about using the brick to cover the surface of the dirt box. Also didn't know if I should use them to hold the soil/litter back and form the fire bowl. I've seen that bricks are used behind the fire bowl to pile charcoal. All new to me. 

I see that there are a lot of questions like this and often times the response is to just go for it.

I have 1"x24" black iron, a 1"x4" nipple, and a ball valve. I am planning on using my 18v Makita floor blower on a very low power. 

Any advice is appreciated. 

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Welcome, BrindleDog. Although I myself am forging mainly with gas these days, when I was working mainly with coal, I did find hard firebrick to be useful for precisely the use you suggest: to cover the surface of the dirt box. Don't try to build the firebowl itself with the brick, but cover everything from about 2-3" outside the bowl to the perimeter of the box with the bricks. This will give you a nice durable surface, and you won't have to worry about your fuel getting mixed up with the dirt fill of the JABOD.

Hope to see you at Quad-State in the fall!

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I would hydrate it all. That way it will pack in. Otherwise, you’ll have clay mixing with you coal/coke/ charcoal making some massive clinkers. 
(Don’t forget to mix with sand and limit the water amount. Doing so will limit or completely eliminate shrink cracks as it dries out.)

Keep it fun,

David

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Not really. Personally, I’ve got a good layer of topsoil and didn’t want to dig a big hole to get to the clay. I hate digging… long story.

For a JABOD, any solid fuel forge really, insulation is not that important. (The typical cast iron fire pot is great, and nowhere near insulated, but I’ve never noticed mine getting hot enough to glow.) If you box is made of wood, you just need enough clay, dirt, etc. to keep the heat from charring it. It doesn’t take that much. If you’re worried about insulation, maybe you could mix perlite into the clay instead of sand. Would cut down on the weight also. That could be a big benefit.

David

I just noticed you location. I believe there is a pretty strong blacksmith group in you area. It would recommend looking them up. One hour spent with experienced smiths: watching, talking, listening to pointers is well worth the effort.

Keep it fun,

David

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When you "hydrate" bentonite or any clayey mix to line a solid fuel forge do NOT  make mud! You aren't throwing pottery you only want it damp enough to pack solidly, if you can squeeze some in your hand into a hard lump that breaks cleanly you've got it. If it crumbles spritz a LITTLE more water on it and mix thoroughly then let it sit a while and test it again. If it leaves dirt on your hand it's too moist spread it out and let it dry a while.

If the mix is wet it will shrink check as it dries like a dry mud puddle and that's not so good. Make sense?

Frosty The Lucky.

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From an old geologist's perspective bentonite may not be the best choice of clays for claying a forge because it expands when wet.  That is why it is preferred as a drilling mud but causes serious problems for houses built on bentonite soil.  Yes, bentonite based cat litter is easily available but, if possible, I'd try to obtain a different type of clay whether "wild" clay from a muddy area or potter's clay from a art supply place or "fire clay" from a hardware store.  Bentonite, particularly if you use even a bit more water than Frosty suggests would be more subject to "mud cracks" as it dries because it would contract more.

"By hammer and hand all arts do stand."

PS Geologic factoid:  Bentonite is named for the locality where it was first described, Fort Benton, on the Missouri River in Montana.  For those who like that kind of trivia.

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Just wanted to say hi to another Buckeye. 

As Goods said the Cincinnati Blacksmiths Guild is there in your city. May want to contact them and see is you could go and pick their brains. Not that folks here wont give you good solid info but in person it is a bit quicker. And i generally retain the info that way better than reading myself. 

There are also several other members here that are from in and around Cinci. The majority of us love visitors and talking about our craft. 

If you are ever up near Dayton, Fairborn specifically, with a couple hours to kill, give us a holler. All are welcome in my shop. 

About those fire brick, i use coal and will use a couple hard fire brick when i want a deeper fire.  However my first propane forge i built used hard fire brick. Worked ok, i could get welding heat. Was it as efficient as the soft, no, but it did work. From what i think i am imagining the use you have in mind it is my opinion that they should work fine. Doesnt seem that much different than when i stack then on my coal forge.  When i built a JABOD i used broken up hard fire brick as a kind of rubble fill as well, then covered it all in clay. 

Anyway, welcome aboard. Stay safe and have fun. 

 

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Hello BillyBones. Thanks for the offer and the info. So what I'm gathering is that hard firebrick is unnecessary in a JABOD. I was planning on making a propane forge until I read that the hard firebrick isn't a good choice. Glad to read that it doesn't need to be over analyzed. I'm really just trying to heat metal occasionally for hobby projects.

I was going to use the cat litter because it was used in the Mark III JABOD post. I'm also a cat guy and have nine cats that I shelter. So cat litter is a material I'm very familiar with. HAHA!  It's all new to me and will take whatever info I can get my brain on. I have plenty of clay soil here in Cincinnati. I like the idea of digging a trench in the ground for a forge but the ground is wet until summer and I don't want to be soaked while working. I believe I live on a fragipan soil (for George N.M.) that creates seasonal pools. It's muddy and miserable during the winter and humid and miserable during the summer. :)

I've seen the forges with the holes in the tuyere and firebrick forming a v shaped channel for the charcoal. I guess these are used by blade smiths? That looked appealing as well. I have access to plenty of material (brick, stone, wood, metal) for whatever configuration. I should probably just make a fire and heat the metal. I'm excited to learn these skills. 

Thanks again everyone. These smaller forums, are to me, the most valuable places on the internet. 

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