Any advice on building a gas forge?

[Robert Suter]

I started making knifes about two weeks ago, I have avoided knife making for a long time, I just felt a bit odd about it. Perhaps because to make a nice knife it requires a lot of nit-picky detail work. Well I got board, so on to something new. After slitting some 5160 truck leaf springs and forging out and getting two blades mostly ground I started thinking about heat treating. I intended to do them just like any tool, but got to thinking about it, so I went to some bladesmithing forum sites to see how the pros did it, and at first I found many people doing it just as I intended. However, looking a little closer at more experienced makers, most have very specialized equipment to do it right. The most controlled method seems to be salt baths like heat treaters use, a high one to bring and hold the blade to just the right temperature and one to quench to just the right temperature. Very controlled and scary if misused. I’m using a coal forge and well I find it’s not all that easy to control temperature evenly especially for long stock without a rebuild and not very friendly to any quench oil. I know I could buy some 1080 and use water but that would be too easy. To gain a little control I’m in the process of building a gas forge, if I live long enough I’m hoping to get an induction forge from Grant. I have a ton or high temp (the 2600 degree soft white kind) bricks, and am in the process of getting the burner design and materials together. I’ve thought about building a baffle to keep the flame off the stock and even out the heat, I have watched guys on youtube playing with blades in the forge to even the heat, does not look like fun or a very reliable method. The crayon or ribbon burner thread in this section looks interesting, but the thread died with little information. Not knowing anything about them or how well they work makes it hard to spend a lot of time figuring out how to make one. 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

[Eric Sprado]

HI Bob: There are so many sites I can't list them all,but if you Google "homemade propane forge" you'll find a bunch. I get along fine with an atmospheric forge but some like forges with blowers... I weld with my atmospheric all the time even though there a yahoos who say you can't... Here is one link to a popular homemade forge site: http://zoellerforge.com/

Good luck.

[Robert Suter]

Hey Eric,
Yes, I intend to use Zoeller’s design. I know how to build a simple forge, what I’m looking for is a new design, a way for a gas forge to have an even heat throughout as much of the chamber as possible. Not having any hands on experience with a gas forge I may be chasing shadows. I’m sneaking up on the question sideways as usual. I suppose I should ask direct questions, but I don’t think I’ll get any answers. From what I have seen of gas forges they have hot spots, I want even heat. I was considering baffling the burners or a 6 or 8 smaller multi-burner system placing them on both sides facing up on the assumption that it would be much like a scaled down kiln. Like I said I may be fixing a problem that does not exist, do you know if a three or four ‘normal’ gas forge has an even internal heat? If I were the first to build a gas forge holding stock in lined box with a rosebud stuck in the top does not sound like the answer, but if it works why fight it?
Bob

[J Wilson]

There are directions and information to build a forge here: http://ronreil.abana.org/design1.shtml

I made one from the Freon tank plans with the Easy burner several years ago. It works fine. I haven't tried placing several end to end, but you could try if you need a longer chamber.

Good luck whatever you build.

[Larry L]

John from Gearheart Ironworks is the person who wrote the artical on the ribbon burner construction in the hot iron news... You really should talk to him.. his number is in the roster... The forges he runs/built have digital temp controllers to hold the temp and with the ribbon you get a very even heat..

[Robert Suter]

Thanks Larry, that’s what I am looking for but I don’t have access to his article from 2005. I’d feel uncomfortable about calling someone up and asking for information they don’t offer normally. Is Mr. Gearhart a member of the forum, maybe he would share his information with everybody, I’m sure I’m not the only one that would like a forge with these capabilities. Maybe he would be willing to write an update article for the site.
Bob

[Grant]

I sent John an email. He's the guy that posted the tong forging jig for the power hammer.

[Eric Sprado]

You guys are right. I plumb forgot about the ribbon burners. The one Ron Wailes brought to the last NWBA Convention would heat stuff up to forging temp while other forges were still at black heat!!!
Ron gives full credit to the inventor of the ribbon burner so I don't mind adding his name here. He is VERY good about sharing knowledge too......

[JNewman]

One thing I have done to try and get a more even heat in the forge was to stick a piece of steel tubing in the forge and after it heats up the work goes in there. It does seem to slow down the heating quite a bit but would work for heat treating. What seemed to work just as well was to heat up the forge then stick a piece of 16 gauge plate in the forge between the burners and the work. I used a piece that went all the way across the forge. The plate was badly warped when I was done but it did spread the heat out quite a bit, preheating the brick on the side opposite the burner is important as it will take a long time to heat it through the plate.
I would love to see more ribbon burner info on here, I have been thinking of putting a ribbon burner in my gas forge both for more heat and also to provide a more even heat for heat treating. I had thought of buying a Pine Ridge Burner, but after reading Dave Hammer's results over on Forgemagic I am having second thoughts.

[Robert Suter]

Thanks Grant, I for one hope he’s willing. That’s a nice jig and it gets my hopes up he is obviously a knowledgeable and sharing guy.
Eric, I’m surprised everybody isn’t all over them, fast heat up and even heat. Sounds too good to be true, hopefully there are no heavy trade offs.
Mr. Newman, using steel for a heat shield is a good idea. Many use them in coal forges, but I was thinking a gas forge would be a prime target for a ceramic one. Not having a gas forge makes it hard to experiment, but if you think its worth a try, find a local potter get him the make you a cylinder with like ½ inch holes spread around it. I would try using Raku type clay first, it stands up to heat fluctuations very well. The easiest way for the potter to make it is by making a slab and rolling it onto a form. I’d offer to make and send you some to try, I’ve got my old slab roller but I haven’t fired up my kiln for many years, let me know if you want to try but can’t get the thing made, I’ll see if I can get it together, I’m kind of curious(ok, stop laughing) myself.
Reading Forgemagic’s forum is like pulling teeth that must be some old software, the burner must take some serious air flow and pressure to operate properly. Hopefully Mr. Gearhart will be willing to let us know.
Bob