gas forge, how much and where can you get one from?

Salem Straub said:
Caution: incoming possibly pedantic wall of text. Take it for whatever it's worth...

You have two main choices- venturi (no blower, also called naturally aspirated) or blown (also called forced air forge).

Many of the gas forges on the market right now are venturi forges, such as the NC tool forges, the Diamondback forges, and the Chile forges. These are the ones that have no blower, and will have one to three burner tubes sticking up, at an angle or even straight. They often will have a flare at the top, such as a bell reducer or a reducing tee (Zoeller's sidearm burners.)
Basically, the fuel line comes off the tank into a regulator, (usually 0-30 psi) flows through a line, goes through a shut-off valve, and terminates in a jet (sized gas orifice) that points down the burner tube from the top. The pressure of the fuel stream entering the burner tube draws air in with it, they mix in the burner tube, and ignite at the other end once they have entered the forge chamber. A choke plate can be added to the top end of the burner to provide some fuel/air adjustment.

A blown burner uses a similar arrangement of forge body and burner tube, but instead of a flared open burner top to draw in air, there will be a chamber larger than the burner tube diameter, in which fuel is introduced (usually through a larger and less critical orifice then with venturi) and forced air is introduced. This air supply likely will consist of a blower of sufficient CFM, squirrel cage or radial, blowing air through large pipe or hose, with a valve or duct gate to control the blast, into the mixing chamber of the burner assembly. Flame adjustments are made with the fuel pressure regulator and the air blast valve.

Both are simple to make. Each is more simple to make than the other in a way. If you want to make your own venturi burners, I recommend going to Larry Zoeller's site and checking out his info and supplies. There are a few parts when making a good venturi burner that may be difficult to track down, and a couple things that you might prefer to buy rather than drill/tap/bore yourself. It all depends on your shop, experience, and tenacity.

If you want to make a blown forge, check out Indian George's tutorial. It explains well. Or, go to anvilfire.com for a good bit of info on making several types of gas forge. Or, check out the material by Stacy Apelt in the stickies here. He's a blown burner whiz.

In either case, the forge body is essentially a piece of 8,10, or 12" steel pipe lined with 2" of ceramic blanket, (you could use castable refractory, but I don't recommend that for a first or general use forge) which is then coated with satanite, ITC-100, Plistix 900F,or some combo of the above. The coating is so ceramic fibers do not become airborne and enter your lungs. Products such as the ITC may increase your forge temps or efficiency as well.

The lined forge body will have a hole coming in the side large enough for your burner flame to enter. Research will indicate if you want to use burner flares or other burner tip arrangements, and how big the hole in the wool needs to be to accommodate this. Generally the burner tube mounts concentrically into a sleeve welded to the outside of the forge shell, and is held with set screws. The fit should be good enough that outside air does not leak into the forge past the burner tube.

Doors can be as simple as cheap yellow firebricks stacked at both ends (easily re-configured into different door shapes, sizes) or as complex as blanket or board lined, hinging or sliding metal ends with small doors cut in, or even movable internal refractory baffles to increase or decrease heat chamber length as needed. I've done all of these, and prefer simple brick and a small forge for most stuff.

You will also see a debate about vertical vs. horizontal forges and much info about the vertical design- it's a good idea, works OK for general purpose but shines for forge welding. For a first forge, horizontal makes more sense IMO. It's a little easier to build, there's more resources out there about it, and it's nice to have a brick floor by the door.

Forges often have floors- and often, this is as simple as a thin firebrick or some kiln shelf laid on top of the wool on the bottom of the forge. They take abuse better than the wool alone, can be easily replaced, and it can be nice to just set stock into the door, resting on the floor as opposed to having to mess with balancing or retaining it somehow at the door so it projects into the forge (this is a common difficulty with vertical forges). Stock can be laid on the wool of a horizontal forge floor, but better to have a hard, replaceable surface there.

Wayne Suhrbier at hightemptools.com will be a good source for materials and info. The company, formerly known as Ellis supply, still has what looks like the lowest prices out there right now for durablanket by the running foot. They have the other coatings and refractories as well as plenty other stuff.

But, shop around. It can really be worth it to compare prices with this stuff. To my mind, buying a forge for $300-$800 plus shipping, vs. building one to my own specs for +/- $100, is no hard decision. Plus, you will have all the fun of doing it yourself.
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wow thanks for the great info. this wraps up a lot of questions I had!
 
My friend built this forge for me.I was a little afraid of the fire/gas stuff also,but its actually quite simple and safe.The body on mine is stainless pipe he picked up at work as salvage.The secret to this thing is the adjustable regulator.It sounds like a jet engine and gets a 3/16" thick 8" blade orange red in a couple of minutes.I usually pick it up(the blade) and move it around under the hot blow to get it evenly colored and hot near the end.Sometimes i lay that firebrick chip inside just to make it easy to pick up.It adjusts in height and has space front and back for firebricks.I love this thing.Other than the s.s. cylinder all the parts were from Lowes and the reg. from tractor supply.I traded for it,but he said he'd build one for $300. like mine or similar.
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Is refractory cement/mortar similar to satanite? I have 40lbs of 3000f stuff that I was going to thin down and recoat the interior of my mini-forge.
 
Salem Straub said:
Caution: incoming possibly pedantic wall of text. Take it for whatever it's worth...

If you want to make a blown forge, check out Indian George's tutorial. It explains well. Or, go to anvilfire.com for a good bit of info on making several types of gas forge. Or, check out the material by Stacy Apelt in the stickies here. He's a blown burner whiz.
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Hello, let me introduce myself, Im Robert, from western NC and while I don't currently do any forging I have been lurking around various forging/knife-making forums. I am interested in seeing the above mentioned tutorial but I cannot seem to find it. I searched for threads started by Indian George and he makes reference to sending the tutorial to Ellis. I looked for it but all I could find were 2 closed websites. Does anyone have a link? Thanks in advance.
 
rodrigr2006 said:
Hello, let me introduce myself, Im Robert, from western NC and while I don't currently do any forging I have been lurking around various forging/knife-making forums. I am interested in seeing the above mentioned tutorial but I cannot seem to find it. I searched for threads started by Indian George and he makes reference to sending the tutorial to Ellis. I looked for it but all I could find were 2 closed websites. Does anyone have a link? Thanks in advance.
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Welcome to Shop Talk Robert



http://www.indiangeorgesknives.com/building_a_forge.html



Stacy did a nice job of this one too.

http://www.bladeforums.com/forums/showthread.php/782574-PID-CONTROL-FORGE-Salt-Pots-and-more
 
rodrigr2006, if you update your profile to include your location, and an email or pm, you may find there is a knifemaker within an hour drive of you. Additionally, check post #'s 11 & 19 by CRex.. the hammer in is just a couple of weekends away (Blairsville, GA area) .. you may not forge but there are knifemakers who stock remove that show up. Check the posts, email him and he'll send you info and you can decide if making the trip is worthwhile. By the way, there are probably half a dozen to a dozen knifemakers in the western part of NC and N/NE GA.
 
Robert
I know a dozen easy and I haven't met them all, in the NGA, TN, WNC area. It boils down to a couple of things.....be a knifemaker or be a serial killer.... Just kidding, but I wonder about some the makers I know. Jorasco is correct, we get a good mix at the Trackrock HI and you are more than welcome. Just be aware that I've managed to mess up a few decent stockremoval boys by putting a hammer in their hand.
Note: Even though Capn R won't give out his real name, you do need to fill out your profile a bit more. I might be able to guide you to a maker in close prox to you.

Seals
Coat that thing! All of the interior and the exposed edges. The forge will work more efficiently be tougher and last longer...your lungs/health have already been mentioned. The additional coating of ITC100 or similar (on top of the satanite) will usually also improve forge efficiency, however the large size of your opening may negate that benefit. Also install a quick cut-off valve 1/4 turn ball valve rated for gas between your regulator and the Lp tank. You do not want to be fiddling around with a multiturn valve if something goes wrong! Also, you will get much more control if you add a needle valve after the regulator. Yes, they are two different things and it does make a difference.
 
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Extended vice grips-Harbour Freight.Quite useful.Decent quality from the cheap tool store.
 
I own two three burner forges, bought them both from Ken Mankel and have never been sorry.

In the Photo I see the propane bottle sitting next to the forge. I strongly advise against this practice, almost cost me my shop and maybe my life.
The bottle goes outside, lines to the forge should be as far from anything hot as you can keep them.
 
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