Freon Tank Propane Forge

Disclaimer/Printing Acknowledgment

 

This page is obsolete, but the information is valid. I am not currently making propane forges this way.

Please see other Propane Forge Pages on my Web Site.

 

 2004.09.13

1. The forge is off balance and might tip over. Move the legs as far forward and back as possible!

2. You might think about bending about 1” of the shortest leg out horizontal and drill and tap for a 3/8” bolt to use and an adjustable foot to make sure all four legs touch so the forge won’t wobble. We ran out of time at the workshop to do that minor mod. It is worth the time.

3. This is the most critical change. The orifice was center punched too deep and the flame burns radically, sputtering and fluttering. The heat is not good and overall bad. The hole needs to have sharp corners, not the chamfer left by the deep center punch. I am enclosing a replacement burner jet tube. Replace yours and mail the old one back to me in the same envelope using the enclosed address label. Sorry for the inconvenience … you will notice the difference in the burner and the forge performance. The workshop was great. I enjoyed working with all of you. Hope to share a fire with you at another meeting. Keep me informed about your progress and new works in your new forge! Send me an e-mail and I will keep track of you that way, if possible. 

Enjoy hammering,
Tom Essary
Home 817-265-1517
tljess@itexas.net

2504 Margaret Dr
Arlington, TX 76012

I had been blacksmithing for about 10 years off and on and had only used coal. In early 1999 I got involved with the North Texas Blacksmith's Assn. (NTBA) and discovered that there were hundreds of other things and ways to express myself in metal and propane forge was one of them. This is my interpretation of the Freon tank forge. I am not a gas and fluid mechanics engineer or a thermodynamics engineer, but this project was easy enough after reading over Ron Reil's and David Wilson's designs and pouring over the photos and drawings. There were dozens of other web sites and I saw about 5 or 6 propane forges in NTBA members' shops. Talking to others and seeing the real machines was what made all the difference for me. Maybe the best advice was from James Ryan ... don't run the forge without insulation in it ... good advice, it would hardly heat bailing wire without it ... after the Durablanket was in place, things went from toasty to bright orange heat. I have heated a 2" bar in this forge ... it was workable ... rolled around ... something of an experience after being used to the constant scotching of a coal and coke. This phase of the project is from around October and November of 2001.

It took me over a year to have the time and amass the materials and experiment to get this done. And if took needing a forge, NOW to finish a project to get this forge working. As others have pointed out, this is not a step by step or a detailed plan, but my way of showing what I have done.

I already have seen that this is too small for some things, but it was a great inexpensive project to get me working at home. My lovely young bride wouldn't let me start a coal fire in the yard, and that is the end of that. This forge makes some noise and the hammering is sorta noisy, but as long as I sell a few things here and there and make her yet another plant hanger, bird feeder, shepards hook etc., she is much more accommodating.

The burner attachment is a piece of 1.5" pipe about 3" long. It is welded to a 1.5" floor flange and the flange is screwed to the outside of the Freon tank. You can make the flange, I happened to buy one at a steel yard for about $2. The piece of 1.5" pipe has threaded holes (1/4"-20) at about 120 degrees apart to hold the burner in place. Any size screw and even one would work. Ron Reil used 6 screws, three at 120 degrees and another three about 3" away ... this allow for lots of adjustment, centering, angle etc. I did not need this in my small forge.

Freon Tank Forge

... Front Left
Before Legs ... in progress ...
You can see a corner
of a split fire brick
as a hard floor
in the forge.

Insulate it before
You try it!!!!!

From the photo, note that I am using a grill size (#20) propane bottle. It will not stand up to a full day of work, but for an hour here and there it has been performing well. It is also easier to move and work around in my garage than a #100 bottle. I was able to buy a #100 bottle at a Pawn Shop for only $20. The valve leaked and when I went to my standard industrial gas supplier for a re-fill, they swapped out the tank for one that was almost new. I am not complaining. I hope you all have as good a luck. I started small, and am working on building up. For me this has been a hobby. As it turns into a profession I will buy bigger and better toys, I mean tools.

Thanks, te

 


For a drawing and some alternatives see my page "Propane Forge My Burner Mod" there is a link from the main page.

Burner Without Jet

Burner With Jet

The curley q thing on the other side of the "bell" is a piece of heavy wire ... about 6 gauge ... brazed to the bell. It is bent to hold the 1/4" rod in the 1/8" pipe ... it is "adjusted" with pliers to center the tube and jet orifice in the center of the 1" pipe ... the delivery to the forge. The Locking Screw is a 1/4"-20 about 1" long. I brazed a washer onto the head for a grip ... "wing nut".

You can make out that there are two more tapped holes in the two faces of the 1/2" nut that make them spaced at 120 degrees. It was easier to add them before I welded the 1/2" nut on. Having several threaded holes allows for changes in mid-stream ... I have already change from a side hole to the one in the back. Also if one hole gets fouled or strips, you are not out of business.

A large thank you to Bill Epps (Mesquite, TX) for suggesting this mounting method. He actually said to machine a block of steel for the mount ... a 1/2" nut worked great and I didn't need a mill ... which I don't have. Also the large hole was drilled, further simplifying things. Bill also suggested that this holder be slotted where it attached to the bell ... more adjustability. The wire loop did that for me ... less complex.

If the nut or other hardware were driller to a much larger ID then the OD of the jet tube, you could use these three screws to adjust the jet tube position. My first drawings used a large piece, say 3/8" x 1" x 3" drilled for the tube with a slot for an fastening adjustment screw/bolt. I will try to post an image of that drawing some time. The 1/2" nut worked great and it was easier to fabricate. The larger item would be great for experimenting to find the correct position for everything, however.

FYI: This drawing shows an adjustable jet holder. I opted to use the 1/2" nut instead. It is far easier to make and I did not need the added adjustment. The rest of the drawing is exactly as in the pictures.
NOTE This seems like too much work and I never tried it ... I include it just and an idea or a suggestion.

 

 

WARNING: Add about 18"-24" of propane hose between the burner jet tube and the cutoff valve! This will keep you hands out of the blaze if the burner flames out. The flame is almost invisible and will cause severe burns. Be careful to keep the hose cool when the forge is in use.

I used a 3/8" gas ball valve. It was cheaper than a 1/4" or 1/8" valve and I needed to buy bushings or hose bards with pipe threads anyway. Just match up the sizes. Also the larger valve might be more useful in a future project when this burner is scavenged/salvaged. I don't see me abandoning this forge for a while, but change is inevitable and I try to plan ahead. (It was donated to the NTBA and Auctioned off after I made a new forge in the April 2002 workshop.)

I like the removable jet tube. This allows me to remove the whole assembly for transportation or storage. Also I can use this tube in another forge or burner, or experiment with different tubes or orifice sizes easier. A turn of the home made wing bolts and the burn is either fastened into place or ready to remove.

Burner Jet Detail

Not a lot of detail ... will try for a better shot. Note the hole --- orifice ... #60 drill - 0.040" is near the end of the pipe where the 1/4" rod starts. This is in the brass ... brownish area ... I drill out the pipe to about 3/16" and braze the hole up. Then the tiny #60 drill doesn't have to work as hard in the brass ... it works for me. You could just use brass pipe, but that is more expensive than galvanized. The 1/4" rod brazed in the end of the 1/8" pipe is another money saver. A 5" nipple was more than twice the cost of the 3" nipple that I used. The 1/4" rod and brazing was cheap by comparison.

Change: In the later design, I only plug the end of the 1/8" pipe (1/4" x short rod welded in pipe end) and use a length that reaches completely across the 2" "bell" through two 1/2" nuts. To avoid the cost of short pipe nipples, I buy 1/8" pipe in 6' or 10' lengths. The cost dropped to about 37 cents a nipple versus $2-$3. I cut to size and thread myself ... the 1/8" NPT die paid for itself in the first use and I use it for all the forge workshops, either planned or impromptu at meetings. By not using a cap on the end of the burner tube, I can remove the tube and keep everything threaded together ... gas tight etc. It also eliminated the hose from being out in the mid air unsupported while in transit, as I take the forge to meetings etc. Similarly for storage the hose is neatly coiled and out of the way an not up in the way.

NOTE: The orifice must have square corners. At the NTBA Gas Forge Workshop in April 2002 the center punch mark was much larger then the drill size and left a "counter sunk" hole. The burner sputtered and the flame jumped around. The punch mark chamfer cause turbulence on the stream of propane.

We brazed up the first hole, filed the area flat and only "slightly center punched" before re-drilling the orifice. Things worked great after that adjustment.

A note about threaded pipe. I cheated. I get the ends and pieces from the threading machine at Home Depot. I ask one of the hired hands if I can had the short pieces that are left after a piece is cut and re-threaded. These pieces are thread and various sizes. I simple weld them onto whatever scrap pipe that I have and I have a pipe the length I need with threads on whichever or both ends. It is difficult to weld the pipe straight as I am a novice welder, but it is excellent practice at a necessary task. 

How well does it work - It works great ... it get to a bright orange heat ... about 2000 degrees F. It is not quick, but I can live with it. I plan to open up the back ... about a 2" x 4" opening and widen the front. As I said early, it is small, what I meant was you cannot get wide pieces in the front, even though it is larger inside. For example I had to re-think how I do a fork ... the second prong is traditionally bent to the side at 90 degrees, but that is too wide for the forge. I had to bend it double, back along side of the handle. It turns out that I like this orientation even better than the right angle method. I have since adopted that as my standard. It is much easier to work the tine out front, without the unwieldy second tine stuck out in the way. I can see it being easier to get into a coal fire and to withdraw also, without the "rake" of a second tine sticking out ... "like a sore thumb".

This burner design doesn't support a flame in open air, but it works great in the forge. My guess is that the forge is too closed up and has enough back pressure to slow the gas down so it will burn in the forge. This might be a draw back and I will find out what happens when I open up the front more, and make an opening in the back of the forge. The back opening will make the forge much more useful. I have only operated it for about 4 hours, and have already found that it is much too short ... for some items. I have however, stacked it full with 4 complete brands and there was room to spare, just none to move too much around.

Regulator vs. Fine Control Valve - First - Safety, you should always have a ball valve or some other quick shut off. Nothing that requires 5 -6 turns to shut off. Other automatic shut offs for flame outs and electrical failures (for blower forges) and check valves are a must. Safety should be first. As for a regulator you can know what pressure you are working at ... you can also duplicate that pressure for future testing or specific tasks. With a fine control valve, like a needle valve, you can count turns for a particular setting, but there is know way to judge flow or fuel consumption, as you might do with a pressure. As far as a regulator goes, however, a needle valve and a gauge near the jet tube would give you a more accurate account for what is going on and eliminate errors due to hose pressure drop. Some designs put the gauge on jet tube opposite the gas inlet. It is apparent that you need some method to adjust the inlet pressure and thus the flow.

More pressure = more fuel flowing, should = hotter forge.

I say should equal, because the perfect neutral flame gets colder with an addition of more fuel. Lots of other factors affect the temperature in the forge. The fuel efficiency drop and forge temperature drops due the turbulence created at the high speeds when the fuel pressure is increased. It is all a balancing act.

 


Last Updated: 2002.04.17
- - © 2000-2007
Comments to: Tom Essary -
www.ad5zo.com
Member - North Texas Blacksmiths Assoc. and ABANA