Gas forge building imput,,,,,, all suggestions appreciated

B . Buxton

B . Buxton

Joined
Jul 8, 2001
Messages
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I've been studying on building or buying a gas forge, I forge mostly blades in the AOL length from 8"-12" but would like to be able to forge and heat treat blades in longer length if ordered. Also I am wanting to turn my attentions to makeing DAMASCUS so I need a forge that will easily reach welding heats. I've read quite a bit on the forge subject and have found that a forging forge will not do a very good job of reaching welding heats, but a welding forge will not do a good job of forging or heat treating because it won't run cool enough.
Have you gas forge users found this to be true? Do you really need 2 different forges,1 to make damascus, and 1 to just forge and heat treat?
I do all my forging and heat treating using coal right now, but the quality of coal I can get easily, isn't much good for obtaining welding heats. Will 1 gas forge do a good job with damascus,forging and heat treating, if so what would you recommend, 1,2, or 3 burner, size of forge 10"x15", 12"x24" smaller or bigger, I would like to hear what size forges you all use, what you do with them, and if would recommend something else. If you don't want to post here on the forum, e-mail me, I would like your opinions.

Thanks alot and merry christmas to all.

Bill
 
I have 5 Bill. A long forge for sword blades, a brick/gas forge/ a coal forge and 2 freon tank forges. I power them all with a mini-mongo burner. No question, I use the freon tank more than anything else with the brick second. I haven't found any problem heat treating in any of them. To reduce the heat, just reduce the pressure.

I use an electric oven to temper.

One note: I am famous for not being able to make good damascus but it is not because the forge is not hot enough. If anything, I run it too hot because I burn up a lot of steel trying to get it just a little hotter. The mini mongo has a lot to do with the heat range. It's a lot of burner for a small forge.
 
Peter,

But what size are these forges, inside , and do you get a good even heat on a long blade, say 10"- 12" without having to move it around with just one burner, and when reheating for welding does it take a long peroid to bring it back to welding heat. When heat treating does the whole blade ( from riccasso to tip) come up to heat nice and even. When making damascus you need a slightly rich flame, SO I"VE READ, are you having to burn to rich with your forges to obtain welding heat. This is what I want to find out in order to establish if 1 forge will do all 3 processes or if you need 2 forges set up differently, and if you can do it with 1 forge how should it be set up.

Thanks Peter

Bill
 
Personal opinion - I think knifemakers that have damascus in mind need at least two forges. One venturi horizontal style for general forge work and heat treating. One blown vertical style for damascus work. I have both - the venturi style has two burners, is 22 inches long,and 10 inches insides. The vertical is 10 inches wide inside, 15 inches long and 12 inches high. It is blown and easily reaches welding heats in foiur minutes running on 1 psi of propane.
 
Both Jim Ferguson and Bill Herndon only use one forge. Not sure of the inside size, but both have doors in the back that allow then to forge and weld longer pieces. Both are two burners.

There is no need for even changing pressure. One day at Bills shop, Bill was doing some pattern welded damascus and Jimmy Roudenbaugh was forging. They were both using the same forge at the same time.
 
I have used a vertical style propane forge with a blower, like Don Fogg uses, for general forging, heat treating and making damascus. It is at an acquaintance's shop and is 24 inches tall and 14 inches in diameter with a one inch layer of ceramic fiber insulation inside. It easily adjusts down to a level where the inside is a nice even red heat for heat treating and heats quickly up to the welding range for billets of damascus. Don Fogg uses a forge like this just for damascus and one with a smaller diameter body for general forging. I fully intend to build the 14" diameter forge with a blower after the New Year for all three purposes and later I will build a smaller version just for forging. With a needle valve to adjust the gas flow, and an hinged cover over the air intake of the blower these forges are as adjustable as you want, at least in my experience with the one I used.
 
Bill I bought mine from Centaur Forge. It cost a bundle but I like it. It is what they call the knife makers forge. It will open on 3 sides but I have the far end and the side closed off. If I want to forge a long piece I can remove the far end. It has 3 verticle burners with a fan. The fan has a door that can be positioned to maintain any constant temp and atmosphere. It has a Regulator 0-15 psi and a valve. I have a thermocouple and pyrometer from Omega so I can monitor and make small adjustments as needed. It will put out welding heat in just a few minutes but the forge needs time to warm thoughly usually about 20 minutes to stabilize and make good damascus welds. Borax is the culprit with welding forges. Mine has a castable refractory floor that has etched away down to the firebricks in about 3 years of welding. I still use it for both welding and forging. I put a mild steel floor in for forging to keep the work off the flux and take it out for welding.
 
Thanks Guys I really appreciate it, I hope some other chime in with there forge experiences.

Bill ????
 
Plain ol Bill has a point on the blower. I have one in the works but still one of my unfinished projects. It would make the forges a little more versitle. I think the reason for burning rich though is to obtain the extra heat. I don't have that problem.

The Freon tank forges have 3 inches of insulation. One is openon both ends and the other is closed. Once the thing gets hot it maintains a good even tempature. The secret is to have a compound angle on the mongo so it blows up and forward. This puts the hotspot away from the steel. For welding you do need to move the work closer to the hotspot but not for forging or heat treating. The brick forge holds heat even better. They can all do a 12" blade with no problem.

The 30 inch forge does take longer to heat and I doubt it will weld well. I've never tried it. It's a special purpose forge.
 
I'm no expert and have no bladesmiths nearby so i got my infro on the internet,ended up building one similar to Foggs vertical forge ,i used a high temp castable refractory,and a blower on the burner its seems to work very well but have never used any other for comoparison,it will not heat up a long length but i don"t think that is a problem as the steel cools before i can forge a longer length.
 
Bill,

Ed uses a Mankel forge and I use a home brewed version of same. Both of us can reach welding heat easily and also have the ability to turn down the heat for forging. You can buy one from Ken or centaur. If you get a mankel I very strongly advise you to put a seperate needle valve on each burner tube. If you would like I can send you a drawing and description of the one that I built. I built my own burner also but spent a lot of time messing around when I could have been forging. I ended up buying a burner from Ken and am very happy with same. I do think it is a good Idea to have a floor in the forge for welding. I made mine out of stainless and slip it into the forge when I'm going to be welding. Makes it easy to clean out the extra flux.


Bill B????
 
I have the 2 burner Mankel Knifemakers forge.
I use it for damascus, forging and heat treating.
To normalize and heat treat, just hold the blade in front of the forge. It will go to non-magnetic in a jiffy.
When I anneal, I just toss the piece in, kill the forge and put the doors on it. By morning, it is cold and ready to go.
It is very sturdy, cast refractory that lasts for years, and cheap to refurbish if ever needed.
It is a tunnel design. I have worked on bars 5' long with no problem. Just insert the bar to the area you wish to heat and away it goes.
Ken Mankel is a good guy and sells anvils, hammers and etc as well.
Enjoy...
 
Originally posted by peter nap
I think the reason for burning rich though is to obtain the extra heat.
Click to expand...

I used to have a home made LP forge (5 gallon round gas can shell, 2" kaowool lining, with an adjustable air gate - blower burner.) I was told that running fuel rich slightly lowered the temperature. But the advantage is that you reduce oxygen in the forge atmosphere, so your billet will scale up less.
 
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