Gas forge burner.

Osbourn

Osbourn

Joined
Jun 27, 1999
Messages
804
My partner and I have been doing all of our forging in a rather poorly designed charcoal forge. It has been sufficient for most of the smaller forgings that we have done, but it's been slow to heat, and bad on the lungs, among other problems. The main complaint is that it can only reach welding temps under extreme conditions, and even then the temps are only marginal.
Last night, my partner drilled a very small hole in one side of some 1/8th in. copper tubing. Then, he drilled a hole in a 2" steel pipe, all the way through, and threaded the copper tubing through that hole. He aligned the hole that he drilled in the copper so that it pointed toward the end of the pipe. Then he crimped the open end of the copper tubing closed, and attached the other end of it to the propane tank regulator. He attached the other end of the steel pipe to a hair dryer, so that the hair dryer and the hole in the copper tubing were pointed in the same direction. Then he turned on both the propane and the hair dryer, and ignited the exhaust.
Surprisingly enough, he survived this experiment. The exhaust was pointed into a temporary forge made of firebrick, and actually reached welding temperature. I hammered on a railroad spike and started to draw it out with this forge, but I had to stop just when I was getting a good start because it was 3am and we were running out of propane. It was surprisingly quiet, and heated the steel rather nicely. With a little bit of reduction of the blower, achieved by putting a hand or piece of tape across part of the back of the hair dryer, a reducing flame resulted.
The next step is to make a good forge for this blower. We'll be using firebrick, the Gingery refractory mix, (One part fireclay, two parts sandblasting sand, and a bit of water) and some rather interesting ceramic blocks for a gas barbeque.
Problems encountered so far have been that we haven't been able to turn the blower up to high because there isn't enough gas to equalize the mix. I think this could be solved with a better regulator, since this one only allows 1 psi. I'm personally very impressed that the burner is efficient enough to work on such low pressure, but I think it will work better with more. I don't think the gas hole in the tubing is the problem. My partner ran this non-stop on a single propane tank that was around half full for in the neighborhood of 12 hours. The pipe got a little hot from radiated heat, but not far enough up its length to heat up the copper.
We'll be building the new forge tomorrow, right after we finish up the furnace for the foundry. I'll be posting pics of all of this as soon as I have a site to host them, likely sometime next week.
Any input on the new forge design as well as improvements for the burner would be greatly appreciated. I hope my description of the assembly isn't too vague.
Thanks in advance.

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Oz

"When your work speaks for itself, don't interrupt."
- Henry J. Kaiser
 
Here's a great page on forge & burner design.
http://www.webpak.net/~rreil/design.html

There is a section on building a forge from a freon tank - easily found in a recycling yard or your local HVAC shop.

There are several burner designs - all venturi, no blowers needed.

Personally, I use a forced air LP burner, but I'm going to try the venturi soon.
 
Please pardon my ignorance, but what is LP?
We actually started with venturi, but the assembly got so horribly complicated that it stopped being fun to try to make. Venturi burners have to have pretty careful alignment to work to full potential. In fact, we were using a design from the page that you linked. That is a very nice design, too. I still can't figure out how we were screwing it up. The blower was the quick and dirty solution that presented itself when we asked "What are we trying to accomplish?". When we realized that all we were trying to do was get a good mix of air and gas, the hair dryer presented itself. I do intend to do a venturi burner as well, though. I'm also looking at the freon tank miniforge design for plans on the larger one that we're making. We were thinking of placing the burner so it goes in at an angle, though. That way we'd have some cyclonic air movement, and a larger heat zone. Maybe. Or, it could turn it into a jet engine, and burn all of our hair off. We'll see.

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Oz

"When your work speaks for itself, don't interrupt."
- Henry J. Kaiser

[This message has been edited by Osbourn (edited 17 September 1999).]
 
LP= Liquid propane

Go to your nearest propane suplier and he/she
will have a pressure regulator and gauge to
outfit your tank. Might be a good idea to
take along your tank to get the right fittings....
goshawk

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http://www.imt.net/~goshawk
Don't walk in tradition just because it feels good!!!!!
Romans 10:9,10
Hebrews 4:12-16
Psalm 91

 
As Mr. Goshawk replied, LP is short for Liquid Propane. Sorry about the confusion.

I'm in the process of building the "Ez Burner." I bought 2 of the stainelss steel flares form Larry Zoeller.

My forge is made from a 5 gallon gasoline can, lined with Kaowool. The floor is cast refractory (Shastacast, I think it was called.) There is a firebrick cut into a triangle on the floor, which works to divide the incoming blast. The work surface sets on top of the divider. So basically, it is a cyclonic heating action, like you mentioned. It heats rather evenly, and it has no problen reaching a welding heat.

Hope this helps!
 
Liquid propane, kewl. We're on the same page, that's what we're using too. My partner is probably at the propane supply store getting our tank filled and getting a new regulator as we type.
I hadn't considered the wedge idea, I think that might be preferable, especially if I make it removable. That way I could concentrate heat in a smaller zone if needed. I've added that to my notes, thanks.

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Oz

"When your work speaks for itself, don't interrupt."
- Henry J. Kaiser
 
Boy, are you guys on the right track!

A few suggestions. If you use a blower (hair dryer) you dont need any kind of a jet at the end of your LP gas delivery tude. A jet is only useful in a ventury type burner where you need to rase the gas velocity to make "venturi action". Make your delivery tube out of ss tube so heat is no problem! I make my burner nozzle out of poreable refractory and make it diverge at the end. I use a paper cup (tapered you know) for the mold of the inside of my nozzle. I will cast the nozzle in a peice of pipe that will get welded to my forge shell. Try not to allow exposed steel on the inside of your forge as it will oxidize quickly and go away! I think it contaminates the forge atmospere also! My delivery tube is right at the small end of the burner. My burner tapers from about 2.5 " at the delivery tube end to about3" inside the forge. I have a 1/3 hp blower and when I run the thing full tilt boogie, it takes almost 15 psi propain to keep up!! The in side of my forge is 18" long and 12" in diameter and I can get the whole inside to welding heat!! Big billets!

This kind of a burner can be turned down to a very low roar with no "pop back". You can't do that with a ventury type.

Oh yea! Standard disclamer: This info is presented for entertainment only! I assume no responsibility if you fold, spindle or otherwise mess yourself or any other nosy person up!

Hope I helped!
Doug
 
The URLs were very useful Ravenclaw, thanks. Here's the latest update. Saturday, we went another go at it. We used two burners this time, on two propane tanks. The forge was a slightly different configuration of gypsum bricks. Building it is a lot like playing tetris. Due to it's inefficiency, we had a very slow start on the heat. We didn't think it was going to work, in fact, as we put a sizable piece of steel in and it didn't change color for ten minutes. Then we went smaller, back to the RR spike. In an hour or so of heating, the bricks were all glowing rather nicely. My parter decided to try to turn some bar stock into a hardy by folding it over several times. I'm proud to announce that we welded that bar stock into four layers and now have a very crude hot cutter. We hacksawed through a portion of it to verify the weld, and it's solid. My parner is wiring together billets for pattern welding as I type. We are going to have so much fun with this thing, but I think we'll do much better when I get some more castable refractory and make that forge. The "Box O bricks" just doesn't cut it. In the eight hours or so that we were working, we managed to make that hot cutter, and turn that RR spike into a knife, and I ruined a nice piece of brass by trying to forge it.
I did the majority of the hammering, so if you'll excuse me, I'm going to go amputate my arm now.

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Oz

"When your work speaks for itself, don't interrupt."
- Henry J. Kaiser
 
I can attest to the capibilities of a freon tank forge Steve Schwarzer made one in about 1 1/2 hours at the Hammer In at Jonny Stouts eariler this month and had it up and running immediately. It comes up to a welding temp in about 5 to 10 minutes and cools off quickly as well. He and Harvey Dean used it to forge all weekend, and it doesn't use a lot of fuel either.

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Curtis Wilson -
Wilson's Custom Knives, Engraving, and Scrimshaw
 
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