Gas Forge Design Basics

[km69stang]

Hello All,

I have been a member of this forum for only a few months and I have read this Gas Forge thread extensively. I myself am in the process of building my first gasser and have gathered most of the information that I require to finish the build.

I have read enough to get the point that 'Bigger is not Better!' To be honest, I never wanted to make something big in the first place. I just wanted something with a chamber of 6 x 6 x 10. I was planning on using kaowool to line it, and have a Jymm Hoffman style to the overall design.

But this is where I have my design issue. I am building a forced air/gas design; I don't particularly care for the atmospheric design. I have the shell, pipes, and jet delivery, but where do I place the tube on/in the shell?

The picture that I have seen of Jymm Hoffman's forge, it has the pipe welded to the side of the shell. But is it welded to the surface or is it sunk in the insulation some. I'm not asking specifically about Jymm's design, but I wouldn't want it excluded either. He obviously knows his stuff. I guess what I am asking is if there is any opinion or tried and true, tested designs of this forge for this specific area? And if there are any other little details that any of you can think of or post pictures of to get the small details, that would be greatly appreciated.

Happy Forging!

Kyle

[maddog]

Sounds like you have made an excellent design choice. This will eliminate a lot of the frustration that often goes with a first forge.

Jymm has a package showing details of his forge design and construction which he is very generous with. If you email him he will probably send it to you.

There are three different issues to consider in your question.

1. At what position and angle should the gas/air stream enter the chamber.

2. How is it channeled from the burner nozzle into the chamber.

3. How do you physicaly mount the burner.

Unfortunately there is a wide variety of strategies.

I prefer to introduce the stream tangentialy at the top back end. Jymm seems to have his tangential across the floor.

Channeling the stream from the end of the nozzle is tricky. This is often the weak part of the forge. The end of burner almost always protrudes partway into a hole in the refractory shell. Some make the hole in the kaowool and line it with protective refractory. I've had problems with this and so I form a nozzle in a block of hard refractory and set the end of the burner partway in.

To mount the burner, many people attach a larger dia piece of pipe directly to the shell and use that as a holder for the burner nozzle. This is popular with atmospherics. This may be the cause of your confusion since it looks like the burner tube terminates at the outer shell but in fact that is just a holder tube. With blown systems, the burner is usually part of the the air piping system which is not flexible. This means the burner doesnt move with the forge like an atmospheric. So any small movement of the forge itself puts strain on the delicate region where the nozzle enters the refractory shell. I like to weld a small mounting frame on the side of the forge and clamp the burner nozzle to it securely. I dont recall exactly how Jymm does this.

[beslagsmed]

Don't know if you got a farrier near you, but most have a gas forge in their rig. Maybe you could take alook at one and get some ideas. Being a farrier I used my Momma Whisper as a basic design when I build my other gas forge. One thing I found I needed to have each burner adjustable where it attached to the forge, and the nozzle adjustable at the top of the burner.

[Jymm Hoffman]

Hello All,

I have been a member of this forum for only a few months and I have read this Gas Forge thread extensively. I myself am in the process of building my first gasser and have gathered most of the information that I require to finish the build.

I have read enough to get the point that 'Bigger is not Better!' To be honest, I never wanted to make something big in the first place. I just wanted something with a chamber of 6 x 6 x 10. I was planning on using kaowool to line it, and have a Jymm Hoffman style to the overall design.

But this is where I have my design issue. I am building a forced air/gas design; I don't particularly care for the atmospheric design. I have the shell, pipes, and jet delivery, but where do I place the tube on/in the shell?

The picture that I have seen of Jymm Hoffman's forge, it has the pipe welded to the side of the shell. But is it welded to the surface or is it sunk in the insulation some. I'm not asking specifically about Jymm's design, but I wouldn't want it excluded either. He obviously knows his stuff. I guess what I am asking is if there is any opinion or tried and true, tested designs of this forge for this specific area? And if there are any other little details that any of you can think of or post pictures of to get the small details, that would be greatly appreciated.


Happy Forging!

Kyle

I just added some more comments to the First Gas Forge thread in regards to the burners, they are into the system, past the insulation just a tiny bit.
The size you are building is really pretty small, at least for the blowers I use. Yes, bigger is not necessarily better. The smallest I will build is using a 12" cylinder, opting for 15" when I can. I found that the burners I build support about 6 inches in length of the shell for every burner. If some one asks me to build a longer bigger one, I ask what they plan to make and if they have a power hammer. If you are strictly forging (pounding hot metal,) by hand, than 12 by 12 is a nice size shell. I still use this size for a lot of work. However, if you think you might have some odd shapes, a cut on one side for such items really helps accommodate many items. Again, check my other posts about gas forges.

Jymm

[km69stang]

I just added some more comments to the First Gas Forge thread in regards to the burners, they are into the system, past the insulation just a tiny bit.
The size you are building is really pretty small, at least for the blowers I use. Yes, bigger is not necessarily better. The smallest I will build is using a 12" cylinder, opting for 15" when I can. I found that the burners I build support about 6 inches in length of the shell for every burner. If some one asks me to build a longer bigger one, I ask what they plan to make and if they have a power hammer. If you are strictly forging (pounding hot metal,) by hand, than 12 by 12 is a nice size shell. I still use this size for a lot of work. However, if you think you might have some odd shapes, a cut on one side for such items really helps accommodate many items. Again, check my other posts about gas forges.

Jymm


I was actually planning on recreating this forge of yours. I wasn't sure on design specs, so I picked what I thought was close, but upon inspection of this picture, along with other information, I now know that my guesstimates were way off. That forge i believe is VERY well designed and look easy to recreate. (given that I can get measurements close) I just wasn't sure where to place the burner.

Another thing, do you place a special tip in the chamber or is it just factory round? I have seen where people flatten out the tips to put into the firing chamber. And I was wondering if you do the same. (I like to ask as many questions from a Master as I can come up with, that I can not find out on my own.) I would be greatly appreciative if you have the time and will, to take many pictures of different angles that you think that is an important detail of construction of this forge. Or any other forge that you think that would be better for a first forge.

Thanks Much for the information.

Kyle

[Jymm Hoffman]

I just added some more comments to the First Gas Forge thread in regards to the burners, they are into the system, past the insulation just a tiny bit.
The size you are building is really pretty small, at least for the blowers I use. Yes, bigger is not necessarily better. The smallest I will build is using a 12" cylinder, opting for 15" when I can. I found that the burners I build support about 6 inches in length of the shell for every burner. If some one asks me to build a longer bigger one, I ask what they plan to make and if they have a power hammer. If you are strictly forging (pounding hot metal,) by hand, than 12 by 12 is a nice size shell. I still use this size for a lot of work. However, if you think you might have some odd shapes, a cut on one side for such items really helps accommodate many items. Again, check my other posts about gas forges.

Jymm


I was actually planning on recreating this forge of yours. I wasn't sure on design specs, so I picked what I thought was close, but upon inspection of this picture, along with other information, I now know that my guesstimates were way off. That forge i believe is VERY well designed and look easy to recreate. (given that I can get measurements close) I just wasn't sure where to place the burner.

Another thing, do you place a special tip in the chamber or is it just factory round? I have seen where people flatten out the tips to put into the firing chamber. And I was wondering if you do the same. (I like to ask as many questions from a Master as I can come up with, that I can not find out on my own.) I would be greatly appreciative if you have the time and will, to take many pictures of different angles that you think that is an important detail of construction of this forge. Or any other forge that you think that would be better for a first forge.

Thanks Much for the information.

Kyle

Take a look at my previous posts with photos about burner tips, as previously mentioned. I show how I make them (flattened1 1/2" black pipe.) While I prefer to put them in the bottom, you may be able to put one into the existing hole, going with 1 burner may be okay for this system.