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a new forge


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As I said in another post lately, I am  tooling up to start bladesmithing again after a 12 year layoff. One thing I need is a forge. The long-term goal is a blown ribbon burner forge similar to Matt House‘s Apollo Forge design:

He put a lot of careful thought into that design, and I love it—especially the ease of maintenance. (It‘s a heavy beast, though.)

 

But that‘s in the future. For the time being I have a T-Rex burner, soft firebricks, and ceramic blanket. I have built forges in the past. There is no reason I shouldn’t be able to have something functional—not perfect, but functional—up and running this weekend.

 

I do not have a design in mind, although I have some ideas. Here are my design parameters:

 

(1) Needs to be reasonably lightweight and portable. I will be forging in the back yard, but I don’t want to leave my forge outdoors. I‘ll need to be able to bring it in after it cools down. Ease of setup and takedown is a high priority. A pile of firebricks would work for my purposes, but I’d prefer a single unit.

 

(2) Needs to be able to heat blades of up to 12“ OAL for forging. I will not be forging swords anytime soon. Welding is not a big priority. (Not that I wouldn’t be pleased if it could weld.) Heat treating will be done in my electric furnace.

 

(3) I like forges with doors. 

 

(4) Components I don’t currently own (I’m mainly thinking of the forge shell here) should be readily available from big box stores like Home Depot.

 

(5) I am equipped to cut, drill, tap, braze and weld.

 

I welcome your suggestions.

 

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If you're comfortable working in a vertical forge like the ones Don used to make, you can't get much simpler or more portable than a modified version of Jeff Pringle's Nuclear Marshmallow.

 

1. Roll up two layers of kaowool to make a tube about 8" internal diameter and 24" tall. Secure with wire binding.

2. make a lid and a base out of a single thickness of wool. You may have to stiffen the lid with wire.

3. poke burner into bottom side about an inch above the floor. tangent or not, doesn't matter.

4. cut doors just below lid.

5. light, wait three minutes, begin forging.

 

It won't be terribly durable, as the wool will be brittle after firing, but if you're careful it can last a good while.  Plus it'll cool off almost instantly, except for the burner.  

 

To forestall anticipated questions from others, no, fired uncoated kaowool is not a lung cancer hazard. Just a dust hazard.  Industry uses it uncoated, and OSHA only requires a respirator during replacement. For dust, not airborne fibers.  It is not asbestos, you can't get silicosis from it, it's no more dangerous than fiberglass insulation. The only reason we put it in a hard shell and line it is for durability. It's too easy to poke holes in an unlined forge, and if you use flux, hot flux eats kaowool like boiling water easts cotton candy.  

 

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My very first forging experience was with a forge very much like this.  Horizontal, 2 inches of wool, inside a cage of fence wire, an old hub cap wired onto one end and some bricks to close up the other end.  The burner was a piece of pipe stuck in the side with a 1/4" copper line from the gas tank in a hole in the pipe.  An old hair dryer provided the air.  It glowed like a pumpkin in a dark shop, and it only had one speed, 2 if you count off as a speed.

It worked and we didn't die, so it's all good.  I think that was the work of Gene Chapman, a mad genius if ever there was one.

 

Geoff 

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"The worst day smithing is better than the best day working for someone else."

 

I said that.

 

If a thing is worth doing, it is worth doing badly.

- - -G. K. Chesterton

 

So, just for the record: the fact that it does work still should not be taken as definitive proof that you are not crazy.

 

Grant Sarver

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5 hours ago, Alan Longmire said:

If you're comfortable working in a vertical forge like the ones Don used to make, you can't get much simpler or more portable than a modified version of Jeff Pringle's Nuclear Marshmallow.

 

1. Roll up two layers of kaowool to make a tube about 8" internal diameter and 24" tall. Secure with wire binding.

2. make a lid and a base out of a single thickness of wool. You may have to stiffen the lid with wire.

3. poke burner into bottom side about an inch above the floor. tangent or not, doesn't matter.

4. cut doors just below lid.

5. light, wait three minutes, begin forging.

 

It won't be terribly durable, as the wool will be brittle after firing, but if you're careful it can last a good while.  Plus it'll cool off almost instantly, except for the burner.  

 

To forestall anticipated questions from others, no, fired uncoated kaowool is not a lung cancer hazard. Just a dust hazard.  Industry uses it uncoated, and OSHA only requires a respirator during replacement. For dust, not airborne fibers.  It is not asbestos, you can't get silicosis from it, it's no more dangerous than fiberglass insulation. The only reason we put it in a hard shell and line it is for durability. It's too easy to poke holes in an unlined forge, and if you use flux, hot flux eats kaowool like boiling water easts cotton candy.  

 

Ah hah! I was thinking of making a forge in an old steel mailbox—horizontal. But I was still scratching my chin about certain aspects of that. Putting it vertical will solve some problems. Good idea.

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I don't know if this would help you, but I picked these up a number of years ago with the intention of building a forge around them.  They surfaced in an outbuilding just the other day.  You'd have to engineer a gas fitting and maybe a choke, but they are a commercial burner.  PM me if you're interested.
 

IMG_20240704_134117570 (Medium).jpg

 

IMG_20240704_134131614 (Medium).jpg

They are apparently burners for a steam boiler

 

g

"The worst day smithing is better than the best day working for someone else."

 

I said that.

 

If a thing is worth doing, it is worth doing badly.

- - -G. K. Chesterton

 

So, just for the record: the fact that it does work still should not be taken as definitive proof that you are not crazy.

 

Grant Sarver

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Indeed.  Back around 1990 or so, a bunch of smiths led by Don Fogg and Jimmy Fikes, in cooperation with Jim Batson, started questioning the conventional wisdom of things.  Jim had pioneered using the hydraulic press for forging damascus in the early 1980s. Always trying to improve things, he and Jimmy (this story in long form is in two issues of Knife magazine from last fall) were trying to weld larger billets without a.) letting them soak in the fluxed-out crap that lines the bottom of a forge and b.) maintaining an even heat.  The vertical forge with blown burner was the result.  Don adopted it, and showed it to everyone in the Knifemakers' Guild. By the end of the 1990s all the big names were using them.  The advantages are great. No leaving the steel soaking in the soup of nastiness, very low scale from the neutral to reducing atmosphere, and a very even heat the full width of the forge.  The disadvantages are that you need a welded-on handle for the billet, or at least one much longer bar you can hold with tongs while it heats up, and the fact that you can't put it down in the forge to soak in heat. Oh, and if you do drop something in it, you have to take the lid off or pick up the body to retrieve it.  Not easy or fun while it's hot.

 

If you're not making damascus, they have no downsides other than the dropping stuff thing.  Think it's not a long enough heat? Make it wider.  I've seen them up to 24" across inside.  And Randal Graham used to heat treat full-sized katana blades by stroking them back and forth through his 8" diameter vertical.  Takes a while, but if you're good you can get an even heat on a long blade in a small forge. They work great with blown or atmospheric burners, but blown are easier to tune.  Well, you have a T-rex, and they're pretty easy as well.  

 

Edit: Geoff posted those sweet ribbon burners while I was typing.  Yowza!  You'll need the injectors, though.  A MIG tip would work, but I have no idea what the orifice size would be or how far into the venturi to put it...  If you made a little side box for those with just the slots exposed to the forge interior they shouldn't melt.  

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They are just cast iron, it would be easy to tap the orifice to hold an injector.  You might even be able to buy the injector from Parker.

 

g

"The worst day smithing is better than the best day working for someone else."

 

I said that.

 

If a thing is worth doing, it is worth doing badly.

- - -G. K. Chesterton

 

So, just for the record: the fact that it does work still should not be taken as definitive proof that you are not crazy.

 

Grant Sarver

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Posted (edited)

Thanks, Geoff. I have often thought that many commercial burners for things like turkey fryers would make perfectly serviceable forge burners with a little modification. In fact I have a  fryer that never gets used. But I think I'm set on burners. If I can just figure out there I put that T-Rex, that is... (It was hanging on the wall in the basement for over a decade. Then I reorganized, thought, "when am I going to use this again?" and put it away somewhere less obvious. That was maybe 6 months ago. Naturally...)

Edited by Matthew Bower
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The present update on my mailbox forge is that I obtained a used mailbox, cut holes in it for the burner and work pieces, dug out my T-Rex burner, and bought some hardware and bits of steel to use for things like legs, a possible work rest, and a burner bracket. 

 

However, it turns out that the ceramic blanket that has been in a trash bag in the basement for over a decade is now more like loose fill than a cohesive blanket. I used it to line the floor of the forge, which I plan to cover with something more durable. But lining the walls of a vertical forge with it just isn't going to work. So the project is on hold while I wait for new blanket to arrive (I am not going to throw the old stuff away; I can still find a use for it. Just not this use. I do wonder if I could glue it into a cohesive mass with rigidizer.) 

 

Turns out I was a little optimistic in thinking I could get this done by the end of the holiday weekend, but it should be good to go by next weekend at the outside.

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  • 2 weeks later...

My new mailbox forge is built, but the interior volume is very small. It's cute, and I think it'll be quite capable for small and medium knives--it should be extremely efficient--but the  old T-Rex burner I planned to use with it is probably grossly overpowered for something so small. As an alternative, I am making a Frosty-style venturi burner, but scaled down--using 1/2" pipe and a 0.023" MIG tip as an injector. I will post pics soon.

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