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I Forge Iron

My charcoal forge

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This is my charcoal forge I just finished. It's made out of a galvy washtub with a 1" blackiron pipe for a tuyere.
I used a fireplace refractory clay I got at home depot. It didn't give the temperature specification on the can, but i think it might not work for forges, because after about 10 minutes the whole fire pot had "bubbles" all over it.
I didn't have alot of charcoal, so i took the few lumps that i had a choped them up into little pieces. That was about 10minutes worth of fuel.
this is with the blower on, its just an old hair drier taped the tuyere.
This is after about five minutes with the blower on and off. As soon as i turned the blower on a huge cloud of sparks flew up at me. I found that I could unscrew the endcap to the tuyere. and it would still get more than enough air. I may work on some sort of adjustable end cap, so I have more control over the air flow.
it almost got up to a welding heat, I think if I had a thicker bed of coals that would of helped.
This is after about ten minutes. you can see the bubbles all over the clay.
Either i got it to hot, or it didn't dry all the way. It doesn't, i'v got another gallon of clay. I'll fix it up , so by the time i get more charcoal, I'll be good to go :D


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andy, you need to let the clay dry completely for at least 3 or 4 days before firing, preferably a week, the bubbles are caused from moisture in the inner clay coming to the surface under the quick dried outer layer.

you also need some kind of air gate to control the air, try sawing 2/3rds of the way thru the pipe with a hack saw and dropping a piece of thin metal in the slot to use for an airgate.

Jr. irnsrgn

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Well there you go. To all those that lament a lack of forging facilities this has to be a shining light to lead the way. Here is the KISS principle applied beautifully for a great result. The rest is just tweaking and fine tuning to get just what you want. Well done Andy. I'm not sure what the clay is but an even more simple approach is to use the clay beneath your topsoil in the garden. It's easily replaced, cheap and readilly available. It is probably just damp enough to tamp it into a nice hollow, layer by layer. As Irn says leave it for a week to thoroughly dryout.

For me though I would reduce the shape of the hollow. The shape I'd go for can be achieved by placing the pointy end of a football (Aussie rules/gridiron /rugby)on the air outlet and packing the clay halfway up the footy. Remove the footy and eh presto a lovely neat ducks nest. this would also reduce the amount of charcoal you'ld use. But heh if what you've got works then go for it. Again...well done Andy.

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Andy, I have almost the exact same forge! It's the Tim Lively design from his website. The only difference is that I didn't cut the slits in the sides for longer pieces of metal, but it hasn't become a problem yet. A deep bed of coals helps with maintaining a higher temperature. Three things I would recommend, first, I used Rutland black furnace cement. I don't remember what the temperature reating for it was, but mine is starting to crack a little. I have another pint of it, so I can repair the liner if it gets too bad. Second, if you use a couple of screws, you can attach a small sheet of metal to the far side of the forge, and that will keep your coal/charcoal from escaping over the edge. Its happened to me many times. Third, if you can find something to elevate the forge, do that. I put my forge inside an old grill. The glass was broken of the cover, so I closed it and the wind can't get to my fire as easily, which helps when lighting it. Also, if you can find some heating coal, it works MUCH better than charcoal. I got a 50 pound bag of it for christmas, I think my parents said it only cost about 7 dollars. I still have about half of it, and I've spent at least 24 hours at the forge since I opened the bag. Good luck with the forge!

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Yip, it's a nice forge.

You have correctly diagosed the too much air problem, and the solutions offered sound good.

Forging when the mud's still wet might be a larger problem than you would expect. You got along fine with a short burn, but a longer burn might cause it to start throwing pieces of clay at you.

Your charcoal looks good -- you might sift it to get rid of that powder.

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I used the cheapest, 100% pure clay, kitty litter from Wally world. I cut it with sand from the beach at about 50% by dry volume and used it for the body of the forge, then used uncut kitty litter clay to line fire pot itself and cap/seal off the clay/sand portion. I mixed the clay and water and let it sit over night and then worked it improve its consistancy. The first lining had large cracks throughout as it dried, then I read somewhere, maybe on this forum, that one should use as little water as possible when lining with clay, worked great. I fired up the forge that day and found that cracking was minimal, the previous lining I left to dry for several days before firing. Not sure if the small cracks formed because I fired it up before drying or if cracking was minimized by my early firing. Either way I've gone back and filled in the cracks that formed with more clay and haven't had a problem since.

As for fuel, check your local hardware store to see if they can order lump hardwood charcoal for you.

BTW: just to cut off any jokes, I used fresh kitty litter.


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  • 2 weeks later...


I cured the clay with a propane torch, that seemed to harden it with out making lots of bubbles.


I rearranged my setup so I could work off the ground. i put my small anvil on the concrete next to the forge


and i sat on a five gallon bucket. but after about an hour of tryin to get comfy, i just unrolled my apron and knelt on that.


This is my first forge weld with charcoal :D . It took me a couple of tries to stick it, but i got it eventually


Its alot harder to tell when your at welding temp in charcoal because you need so much more coal on top, you cant see the colour of your metal, and cause there are so many sparks and embers shooting everywhere you cant see if your metal is burning.

I worked for 3 hours and burned almost eight pounds of charcoal. I paid about $5 for an eight pound bag. A bit pricey compared to blacksmith coal, but its still cheaper then propane.

Plus, I love the smell of it... and the clouds of smoke that waft thru my garage and dance off the light that pours the windows and the cracks in the siding......ahhhhhhhhhhhhhhh

Hehe. I remember now why I got into this stuff, Its so much fun....


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Good work! Is that a Wilkinson anvil? You may want to get a kneepad if you plan on working on the floor consistently. If I were you I would cut that weld in half crosswise with a hacksaw or similar and check for a line across it, to see how it came out.

Dunno about cheaper... takes me about 12 hours to burn $12 worth of propane. Price might have gone up since I last filled though. Doesn't matter anyway, charcoal looks like fun! :)

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ok, I've attempted multiple forge welds with coal, not high quality blacksmith coal though. Every time, I find a fault in the weld, or I burn the metal. Did you use any flux to make the weld? I tried using ash from the forge, with no difference. I've also tried without any flux at all, and thats how I got my first, and only weld. Though it was not pretty. I burned most of the metal around the weld. I've only tried it with 1/4" round stock, I want to try with 1/2 inch though.

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Well, first of all. If your not using blacksmith coal, that probably means your using anthracite, or charcoal, which one do you use?

"Every time, I find a fault in the weld, or I burn the metal."
Most common mistakes with forge welding is not getting it hot enough, or getting it to hot and burning the metal. Both will result in poor or unsuccessful welds.

Its something that just takes alot of time and practice to get right. Try getting a piece of steel up to the point when it just starts to throw off one or two sparks, it should be a very bright lemony-yellow colour, any hotter and it will burn. That is your welding heat, You should start out with some simple welds , like the one i did in the photo. Take a 1/4' or a 3/8' rod and bend about an inch or so of the end back around onto the rod, hammer it so that the two surfaces just touch each other, bring it up to a bright red colour wire brush the surface clean then flux with borax or whatever flux you use, then bring it up to a bright whiteish-yellow colour, just when you see one or two sparks , take it out and quickly give it a few soft hammer blows.

If you want I can go into more detail on how to forge weld, or I'm sure one of the other guys can.
Hope that helped ya Rantalin


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Well said bp. Fire welding may seem almost impossible the first couple trys, but once you get a weld, it feels great. Keep at it; the boring but true old saying---practice makes perfect. (or at least real good :) )

BTW i would recommend using commercial coke- more expensive than coal, but lasts much longer and burns much hotter/clean. Excellent for welding too.

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Wood ash has sometimes been used as a flux for forge welding; coal ash is a contaminent that helps prevent welding. Borax is the most common flux used for regular modern steels.

One other common mistake is to use too much air making for an oxidizing fire. You want to bring the temp up slow and steady not a massive fireball effect. If the outside of the piece gets to welding temp while the inside is still "cold" then you can get a partial and very weak weld even if it looks ok...

Make sure your fire is deep enough to use up all the O2 before it gets to your piece!


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