The ol' Forge Question

Burchtree

Burchtree

KnifeMaker & Moderator
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Yes, it's been asked a million time, and I've read them all. Currently, I'm working with a pile of firebricks and a fish cooker burner. It works well, but uses a lot of propane and I think it's time to build a forge. I've looked at every set of plans out there, and still don't know what to go with. I want to use it initially for heat-treating my blades, but not use as much propane as my current set-up. I also want a forge so it can "grow" with my knifemaking as I would like to get into making some mokume and later, some bladesmithing.

I know this is kind of a loaded question, as everyone has their personal favorites -- but what should I go with? I want it to be propane-fueled, but fairly inexpensive (this "hobby" gets expensive! :D ) and maybe something I can use in the garage, if that's even an option (where do you guys have them?)

I know, I'm full of questions today, but I've been thinking about this for a while.

Also -- I'd like to be able to treat both small, and large blades.
 
So you use the firebricks instead of the "tube" as the body of the forge? What are you using as a blower?
 
The only bricks are in the bottom of the forge to catch the flux. The blower adds the volocity and oxygen to the the propane for a hotter flame. With my forge I can weld at 4 to 5 psi, where as venturi needs 12 to 15 psi.
Forge Parts

Blower Part # 16-1032 $18.99
Vendor Surplus Center
Phone Number 800-488-3407

Black Pipe

1.5 inch
Nipples
6” & 4”
90 deg. Elbow
Coupling
¼ nipple 6”
¼ cap
2 sets of ¼ inch quick disconnects with o-rings
8’ of hose

MSC (800) 645-7270

Page # Item # Description $$$$

3341 8557803 Nuline Regulator $20.89

4030 00075929 Needle Valve Female $20.32
(1/4 NPT )
 
I use stacked fire bricks. One box of bricks will build two forges the are approximately 4 x 4 x 18 inside dimensions. I use a single venturi Ron Reil style burner with a #60 hole for the LP jet. On a 20 pound tank of propane I can run for about 8 to 10 hours at welding heat (about 13 psi).

Fire Brick 2600 deg: $58 for a box of 25
Burner Parts: $10 for two burners.
High Pressure Regulator and misc fittings: $40

So $108 for two forges, not bad in my book. Easily made smaller or bigger by stacking the bricks differently. I have mine in the basement with a 1200CFM blower above it. Here is a picture:

shop1.jpg
 
I've just completed my gas forge, the burner I'm using is a bastidization of all the venturi burners I've seen and loosely modeled on one I've seen Jerry Fisk using as his traveling forge.

Parts list:
1-2" to 1" bell reducer
1-1"x8" nipple
1-3/8" cap
1-3/8"x8" nipple
1-1/4"x5/8"x2" mild steel
Misc odds and ends to connect to propane line

Center drill the mild steel for the 3/8" nipple, drill ends for mounting screws to mount steel onto the 2" end of the bell reducer/venturi.

Drill and tap the 2" portion of the bell reducer to mount the mild steel bar.

Drill the 3/8" cap for a nozzle (I'm running a #59 hole).

Fit the drilled cap to the 3/8" nipple, solder/weld to ensure leak free joint.

Slide nipple through drilled steel bar, mount bar to end of bell reducer/venturi.

Connect to gas fitting, check carefully for leaks and fire her up!

I slide the burner back and forth til I get a good flame, the sweet spot changes depending on wind speed outdoors. :confused:

I welded up my first bit of wire damascus this weekend using this burner in my small (180 cubic inch) forge with 2" of Kaowool. It runs real economical in the small volume forge.

***I can not accept any responsibility for any injuries or damage incurred using this description. Sorry :barf: gotta do that.

Will Leavitt
 
Laredo -- I'm assuming your blower is to blow fumes out of your basement right? If that's true, you forge doesn't have anything pushing extra "heat" into the forge. Does that make a difference?
 
Yup, the blower is to exhuast heat and fumes. Well, fumes when I am burning out cable and CO and CO2 all the other times. The blower works so good that I can even smoke while forging and you can't smell it in the house at all.

I don't have any blower attached to the burner. The jet of LP shooting down the burner tube body sucks in all the air it needs to burn. With the #60 jet size, I have a slightly rich mixture, so oxidation inside the forge is not an issue. I use this forge for everything I make, mokume, cable damascus, regular damascus, and general forging.

The one burner will get the back 2/3 upto welding temps, the front 1/3 stays a little cooler. I have the back of the forge blocked off with a firebrick that stands vertical, so all the "dragon's breath" comes out in front.

I think blown burners are more efficient and adjustable, but I have not had any problems with mine. I don't even run the flame stabilizer (burner flare) anymore. Yeah, she spits and spudders a bit once you first light it, but after a couple minutes of warm up time, she purrs like a kitten.

Anyway, let me know if you have anymore questions or if you want some better pictures.
 
Got any pics of the attachment of the nozzle/etc. to the firebrick?

Do you do all your heat-treating out of it too, or are you an oven man? If you do, what do you heat up your medium with? I usually set my ammo can on top of my firebricks to get up to 140.

Sorry about all the badgering, but here is my "leaning tower of heat-treating." It works though -- just wastes a lot of propane and I sure can't do any forging with it.

attachment.php
 
Michael,
Looks like the only thing you're missing is a burner :D I built a firebrick forge like that when I was prototyping burners, I just cut a brick in 1/3s and left one section out for the burner to enter.

You should be able to find fittings that connect the burner to that hose at a good hardware or welding shop. Just take the hose in with you. I'd add an inline "oh sh$$" ball valve.

About $15 more and you got a forge. :D Least from what I see in your picture.

Will
 
I just have my burner wired to a piece of flat stock:

burner.jpg



Here is how I do my heat treating:

saltpot.jpg


I use a molten salt HT contolled to 1550 deg F. I heat my oil with another piece of flat stock that i heat up in the forge and then quench into the oil. Not real scientific, but effective.
 
Here's the burner I built:

http://www.geocities.com/zoellerforge/sidearm.html

I use a propane regulator from a coleman stove. Probably doesn't allow the full force but works well.

A key componant is a flared nozzle. I made mine, but this guy sells 'em: http://www.geocities.com/zoellerforge/flare.html


For a jet I have a 1/8" brass nipple with a .040" hole. That's it. Really works well.


For a forge I have an 8" (maybe it was 9") pipe, 24" long. 2 insulation-type fire bricks in the bottom and 2" of wool as a liner. Then a circle of sheet metal (looks like a giant washer) over each end to hold it. 4 legs and bingo.

I can post of picture if you'd like.

Burner was about $20 in parts. I think the forge was another $40 or so. Mostly for the wool and bricks.

Steve
 
Thank you gentlemen for your help.

Laredo, I appreciate the pics a lot -- I think I might see what I can build.

If I do plan on revamping mine, It will serve mainly as a more efficient heat-treating unit until I learn some more about forging. Does the valve heat the compartment evenly enough to heat-treat long blades? I can do them with mine, but it takes some work.

(I promise I'll stop asking questions one of these days.) ;)
 
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