Any advice on building a gas forge?

[Grant]

Yeah, I guess we need to make listening noises. We're watching and listening.

[StevePMcGrew]

... So what do you guys think about using a baffle, they may not be necessary or may be detrimental in an open forge as I have not seen one in a forge just in fuel burning kilns, but I don’t get out much. Do multiple burners help even out internal temperature? Does anyone have advice or opinions on gas forges?
Bob

Bob, I've tried several things: a pipe, a brick baffle, and stainless steel envelopes both in my coke forge and my gas forges. They all work pretty well, but of course in a coke forge you need to pay close attention or you'll burn through the pipe or envelope. Most often these days I use a brick baffle *and* a stainless envelope, in a two-burner gas forge. I used John Emmerling's ribbon burner forge at a recent NWBA conference, and it was amazing. Almost have all the components gathered to build my own ribbon burner forge.
Steve

[david hyde]

OK, the body is mortared into the shell.

I feel like I’m talking to myself, that’s not good. I’ll stop now, before somebody notices.

Bob, I'm listening.

One observation, not a criticism, is I wonder how easy it will be to replace any bricks. I make my forges with soft firebrick vertical walls, hard firebrick floors and fibreboard roofs. Over a period of time the wall bricks always seem to develop a few cracks, but more important constant dragging irregular work in and out tends to knock/ bump/scrape against the bricks. This eventually damages and wears them to the point where they replacing. Its easy to lift up the roof and swap bricks over.

I dont like castable because it has too much thermal mass and too little insulation for my purposes. It lets out too much heat into my workshop and acts as a big storage heater and keeps on heating the workshop well after the gas is switched off

I don't like ceramic wool because the irregular shapes of my work I use catchs it and easily rip it out. Spraying it with rigidizer helps but not much

I tend to get cracks in the fibre board around the holes I drill to let the burner flares in. I'm gone try a ribbon burner sometime but suspect the fibreboard may not stand up as well with a large square hole cut in. I like the "arch" construction off yours, especially using moratr rather than just stacking the bricks. It seems a neat solution to the constant problem of what to use for the roof (floors and walls are easy). I'll be real curious to see how yours hold up with use.

Re doors, my preference is doors that lift up and down with counterbalances. They are quick and easy to use and minimise the heat lost when opened

[JNewman]

Bob, I'm listening.



I don't like ceramic wool because the irregular shapes of my work I use catchs it and easily rip it out. Spraying it with rigidizer helps but not much

A friend of mine has a solution to this. He found some inconel sheet at a scrap yard and lined his forge with the inconel. Last time I saw him it was still standing up after about 5 years of full time blacksmith use.

[Larry L]

I just begged some small chunks of inconel to use in a forge project... glad to hear Its got a chance of working!

[Robert Suter]

OK, I really thought I was boring you guys to death with this thread. Knowing just one member of the few that post has any interest indicates to me the many members who never post may have an interest in the outcome. Having such a response is very encouraging, but if I had known I would have cleaned up my act.

Lordcaradoc, it should get easier if my ideas on burner assembly ideas work out, hang in there.

True Grant, a wink is as good as a nod to a blind horse, or mule in my case.

Steve I’m hopeful the ribbon burner will make the baffle unnecessary, not having a burner with a major hot spot and circulating the heat should work.

David, this forge is a means to an end, it will spall and crack no doubt if it gets to see that much use. Like many of my adventures it has brought to me a set of ideas to build the forge I envision. I am eager to begin work on it but feel obligated to finish this forge first (I often abandon iterations of projects when I find a better way that will not fit the old build) besides the forge will give me a chance to test my ribbon burner assembly ideas.

Jerry, I would love to have some of that to play with, I imagine it’s not cheap to obtain.

The truth is for forging the induction forge is the master no doubt, and for heat treating specialized kilns and salt pots are the pinnacle of control, gas forges are a compromise at best, but probably the most obtainable for many.

*edit, Larry, missed your post, tell us more, what are you making with small chucks (perhaps I should ask, what’s a small chunk to a metal monster?) in a forge?

[John Emmerling]

OK, I really thought I was boring you guys to death with this thread. Knowing just one member of the few that post has any interest indicates to me the many members who never post may have an interest in the outcome. Having such a response is very encouraging, but if I had known I would have cleaned up my act.

Lordcaradoc, it should get easier if my ideas on burner assembly ideas work out, hang in there.

True Grant, a wink is as good as a nod to a blind horse, or mule in my case.

Steve I’m hopeful the ribbon burner will make the baffle unnecessary, not having a burner with a major hot spot and circulating the heat should work.

David, this forge is a means to an end, it will spall and crack no doubt if it gets to see that much use. Like many of my adventures it has brought to me a set of ideas to build the forge I envision. I am eager to begin work on it but feel obligated to finish this forge first (I often abandon iterations of projects when I find a better way that will not fit the old build) besides the forge will give me a chance to test my ribbon burner assembly ideas.

Jerry, I would love to have some of that to play with, I imagine it’s not cheap to obtain.

The truth is for forging the induction forge is the master no doubt, and for heat treating specialized kilns and salt pots are the pinnacle of control, gas forges are a compromise at best, but probably the most obtainable for many.

*edit, Larry, missed your post, tell us more, what are you making with small chucks (perhaps I should ask, what’s a small chunk to a metal monster?) in a forge?

Come on Bob, just make one. If you're really into smithing, you'll make many forges. Each one is a learning experience, and you'll get better with those that are successful and those that aren't. Ultimately, each forge has its own characteristics and usability. You will learn by doing. There is no substitute for experience. The internet is just the beginning. Now, turn off the computer, build a forge, and show us what you made...good, bad or ugly. Please remember, we're all in the same boat.

JE

[Robert Suter]

Ok John, isn't that what I'm doing? The idea was to let those who have never picked up a brick see how it can be done. I’ve not gotten into it deeply because it is much easier to use koawool or castable products than brick and nobody has asked. As for the burner, I’m not one to follow the crowd, it may be the safe and easy way, but I have my own vision, right or wrong. This forge will be finished in its time, I’m about to post something about one of the things on my mind right now. A recuperative forge I’ve been thinking about for some time, with your help and the help of others all the pieces have fallen together. I’m just having a problem on how to present it to the world. Maybe you’ll have an idea.

[Robert Suter]

I sent this to Able Refractory Products today:
"I’m designing a recuperative heat, metal work forge (blacksmith forge). I am seeking the best materials to build a small, hard surface, non-insolating internal shell. The shell will be subject to thermal shock, steel banging the internal surface at high temperatures and exposure to welding fluxes (borax, boron). I understand no refractory can permanently withstand these abuses, I am looking for the best compromise. The design will recover the heat from the external surface of the shell drawing air from between the shell and the outer insulation. The heat source will be a ribbon burner (glory hole type) to minimize hot spots on the shell. Its design is a three piece approximately 6 inches round, barrel shaped and between 12 and 24 inches long, fit together in the long axis. Please advise me as to which of your products you feel will be best suited for this design."


I believe I have thought of a way to make a small recuperative heat gas forge. I’ve got the basic design planed out, it is a set of simple ideas using good old well known physics but it’s complicated to build, and needs to be perfected. I’d like to make money building these forges but I don’t have the resources to do so. Giving away the idea won’t help anyone but those with serious resources, and they don’t need my help. It’s quite a quandary and I don’t know how to proceed, I suppose it will just be a matter of time. It just irks me to no end, I am used to not being able to take financial advantage of most of my ideas but I don’t know how I can even give this one away. And I think this is a really good idea. I don’t see what advice anyone could offer that would help, but I’m asking if you have any ideas, please help. Everything I think of seems off the wall and impractical, like that should bother me, but it does need to work.

[Jymm Hoffman]

Jymm Hoffman,
Where did you go? Did you forget about us? I really think you should at least start a thread in the forge section here, I think others should have the advantage of the knowledge you have so generously offered. Your burner and forge information may be lost in this tread or at the very least under exposed. I would like to ask you some questions, start a thread and I’ll ask there instead, more information in the proper place is better in my opinion. I believe your ribbon burner has it’s tip exposed to the forge heat, have you shut down at high heat and checked to see what the heat back up into the chamber was? The tips you make are fairly massive in comparison to the tube type but are exposed to more free air out of the forge this looks like an advantage in ‘back up’ heat loss. Do you notice much heat erosion or heat stress cracking at the tips?

Sorry for not checking in for a while. I was really busy doing shows this fall. Still have questions? The burner tips are just at the edge of the refractory. If they stick into the system too far, they do scale up and eventually scale to nothing after it is shut down. Then they are more open than when first made and don't work as well. If they are kept right at the edge, they will last a very long time. If they don't last and scale away replace them. I have actually had less burn out with these than I did in a previous system with supposedly heat resistance alloy steel commercially made burner tips. Kind of funny how the much cheaper burner tips last longer, especially when not worried about them burning up.
You can actually see one of my systems in action in a You Tube video John Thornton made of me: YouTube - Jymm Hoffman, American Blacksmith