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milomilo
08-21-2011, 08:55 AM
Yesterday at the auction I picked up this gas forge. Been considering making my own with no idea how to do it. It has Johnson Iron Works cast into the blower assy. Net says they are still in business, so I will be contacting them to see if I can get a manual for it. Looks to be in real good condition. Blower motor spins freely. Wiring for the blower switch is on top of the forge.

It has a height adjustable swing over cover filled with refractory and 4 burner outlets. Unloading today and checking out the electrical on the blower. It has a electrical magnetic switch inline on the gas. Not sure how that works yet.

Nice part is I got it for $15. Can't even think about making my own designed crappy one for that price. It has 2 knobs that adjust the gas flow into the burner area. Not sure how to set/adjust them yet either. Anyone seen this type of forge before and can help me with the magnetic switch thing or operating/lighting instructions?

milomilo
08-21-2011, 08:58 AM
More pics.

tnmike
08-21-2011, 08:59 AM
Yes I have seen them similar to this before. They use a LOT of gas. The open design allows a lot of heat to escape and kills the efficiency. For fifteen dollars you did really well. The new ones like this cost about 4 grand.

I can get you some details wednesday. I will have eyes on a new one. This will get you to a website and instructions. Lighting them is a matter of turning on the gas and taking a long piece of burning paper to the interior of the forge body. The magnetic switch is a safety feature. It cuts the gas off in case of a power failure. You have to hold a button down while you light it.

The ones I am familiar with are natural gas. Im not sure what you need to do to convert them. Im thinking they might be Johnson but I really cannot remember.

Scotts
08-21-2011, 09:05 AM
Chris,

The magnetic switch is a solenoid valve. Look on the small plate under the nut that holds it together. The name and number should be on that plate. You can google it from there. It is probably a normally closed valve. apply power to open and turn off power to close. This forge was probably used in a building with the fuel piped directly to it and used this valve to turn off and on the gas. If it is newer it may have been some sort of safety devise. Looks like it has some sensors in the lid as well?

Scott

tnmike
08-21-2011, 09:13 AM
Here you go..i was right on my memory. The two burner is 200,000 btu/hr per hour gas usage. I would crank the lid up and block the sides and back up with firebrick/ It would save fuel and cut down on the heat. You can also cut the propane pressure down . The ones I have used on natural gas put a LOT of heat out into the room they are in. They are industrial use forges where the spaces are big and costs dont matter.

http://www.johnsongas.com/industrial/frn-forge.asp

milomilo
08-21-2011, 09:43 AM
Here you go..i was right on my memory. The two burner is 200,000 btu/hr per hour gas usage. I would crank the lid up and block the sides and back up with firebrick/ It would save fuel and cut down on the heat. You can also cut the propane pressure down . The ones I have used on natural gas put a LOT of heat out into the room they are in. They are industrial use forges where the spaces are big and costs dont matter.

http://www.johnsongas.com/industrial/frn-forge.asp

Thanks much. I think with the swing over cover it should hold in the heat better than a wide open forge.

tnmike
08-21-2011, 09:54 AM
I think with the swing over cover it should hold in the heat better than a wide open forge.

The swing over cover allows a LOT of heat the escape. I have used about every kind of forge there is and this one puts more heat into the room than any other I have used. There is no flue taking heat away like an open forge. You could build a hood over it with a forced fan draft that would make a lot of difference.

Try it as is and try it with firebrick blocking off the sides and back and the flame cut way back. You got a killer buy either way.

I think this is the manual for one you have..Yours is an older model but its basically the same.

http://www.johnsongas.com/industrial/manuals/pdfs/122DirectSparkNoSafety.pdf

You can light this type forge with the blower running and the gas on without an electric starter with lit newspaper. Just done have your face over it when you do.

tnmike
08-21-2011, 10:35 AM
Here is a little forge I use about all the time. Its naturally aspirated(no blower) and will run on one pound of propane. It will forge weld on fifteen pounds of propane. Ive probably got six or eight forges I have made over the years ranging from coal to gas , forced air and natural air. This one was made by a friend of mine in Cosby, TN and sits on a take down square tube stand. Its has a castable refractory lining.

I thought you might be interested.

milomilo
08-21-2011, 01:10 PM
I think with the swing over cover it should hold in the heat better than a wide open forge.

The swing over cover allows a LOT of heat the escape. I have used about every kind of forge there is and this one puts more heat into the room than any other I have used. There is no flue taking heat away like an open forge. You could build a hood over it with a forced fan draft that would make a lot of difference.

Try it as is and try it with firebrick blocking off the sides and back and the flame cut way back. You got a killer buy either way.

I think this is the manual for one you have..Yours is an older model but its basically the same.

http://www.johnsongas.com/industrial/manuals/pdfs/122DirectSparkNoSafety.pdf

You can light this type forge with the blower running and the gas on without an electric starter with lit newspaper. Just done have your face over it when you do.

Thanks for the manual, but I'm not sure it is the right one. My forge has Johnson Iron Works from NE on it and this manual says Johnson Gas Works. Different companies???

tnmike
08-21-2011, 03:06 PM
Its pretty much the same design as the new Johnson gas forges so I would say they are closely related if not the same company. Youve got enough info on the Johnson website to get yours going. There are about five different manuals for the two burner forges depending on what safety equipment is installed on them. This is the only UL approved gas forge. The local community college got into it with the local fire marshall and had to buy five of them at a cost of 20 grand. The drawback as I see it is the amount of fuel they use, the up front cost and the amount of heat they put into the room and on the operator. You can literally watch the gas meter whirl around like a clock when one is running.

I would take it outside, hook a gas bottle to it and light it. Ive seen forced air forges where the gas was run into an elbow with a copper tube and lit after the fan was turned on. Crude but it worked.

USMCPOP
08-21-2011, 03:22 PM
The Johnson Gas Appliance Co. has been in business for over 100 years. I see references to the same company name from the early 1900's. The Johnson Forge blower may just be a part on there. Johnson Gas is in Iowa. Maybe a coincidence or some relatives in somewhat related businesses.

milomilo
08-21-2011, 04:29 PM
Its pretty much the same design as the new Johnson gas forges so I would say they are closely related if not the same company. Youve got enough info on the Johnson website to get yours going. There are about five different manuals for the two burner forges depending on what safety equipment is installed on them. This is the only UL approved gas forge. The local community college got into it with the local fire marshall and had to buy five of them at a cost of 20 grand. The drawback as I see it is the amount of fuel they use, the up front cost and the amount of heat they put into the room and on the operator. You can literally watch the gas meter whirl around like a clock when one is running.

I would take it outside, hook a gas bottle to it and light it. Ive seen forced air forges where the gas was run into an elbow with a copper tube and lit after the fan was turned on. Crude but it worked.

The forge wiull be set up outside as I don't have a building to put it in anyway. When not in use it will be covered.

bluechipmachineshop
08-21-2011, 10:03 PM
Now I understand why you are the Wyoming Auction Addict. Great deal for 15$.

Mick

milomilo
08-22-2011, 12:11 PM
Now I understand why you are the Wyoming Auction Addict. Great deal for 15$.

Mick

I rearely ever went to an auction until retiring and moving here in 2006. Now it is my main hobby and it has made me some nice money too reselling some of the stuff. Kind of pays for most of my "hobby".

milomilo
09-04-2011, 03:10 PM
Got the forge all checked out yesterday. It is a 4 burner forge, but I have shut off two burners for the initial lighting test.

The switch was a little iffy, but cleaned it up with contact cleaner and it works perfect now. The motor for the forced air works great. The gas solenoid valve operates as it should, i.e., closed when power shut off to the motor and on when the blower is on. I have 3 or 4 LP regulators. I can't tell what each of them have for output pressure.

I picked one and when trying to light the forge it acts like it is not getting enough gas. Tried adjusting the air input at the blower from almost closed to halfway open with no difference. I am using the O/A torch for the starting.

Anyone know what the output pressure of the regulator to the forge should be? How can I tell what output pressure of the regulators I have are? Is there some sort of code involved?

Pics are of the regultor I used.

Edit: The link from TNMike says it should have 6 psi pressure to the forge. Maybe my regulator has too little output pressure????

milomilo
09-04-2011, 10:07 PM
tnmike:

Do you have any advice on my LP regulator for my forge???

Scotts
09-04-2011, 10:42 PM
Chris,

I see 6 ounces in the manual linked above. 11 inches of water column in the other link with the pictures.

regulator information (http://www.propane101.com/regulators.htm).

Scott

milomilo
09-04-2011, 11:08 PM
Chris,

I see 6 ounces in the manual linked above. 11 inches of water column in the other link with the pictures.

regulator information (http://www.propane101.com/regulators.htm).

Scott

In your link it says most LP tanks are around 6 ounces of pressure. Does that mean I do not need a regulator and just control the flow of gas using the manual valve at the forge?

Scotts
09-05-2011, 12:11 AM
In your link it says most LP tanks are around 6 ounces of pressure. Does that mean I do not need a regulator and just control the flow of gas using the manual valve at the forge?

That part I will have to study up on. I would have to guess that would be regulated pressure. I seem to recall that pressure in the small grill lp tanks can reach 150 psi in the sun. Here is a copy and paste out of the link.

Regulator Purpose

Propane tank pressure can range from under 10 psig to over 200 psig. Residential applications will generally require 11 inches water column (amount of pressure required to push a column of water up 11 inches in a manometer, or about 6.3 ounces per square inch) and the regulator compensates for these pressure differences in the tank to supply a steady flow of required pressure to the household appliances. Not all applications are similar to that of residential use and will therefore utilize regulators for higher and lower pressures as required by the appliance(s). In summary, the purpose of a propane regulator is to "bottleneck" the propane down to a safe and usable pressure. An important point to note is that under normal operation, a propane regulator will make a "humming" noise. This is normal and should not be construed as a problem or regulator malfunction

I don't think I would try this without a regulator.

Scott

cutter
09-05-2011, 12:33 AM
I don't think I would try this without a regulator.

Scott
:)
meither.

I ran across a natural gas cook stove a few years ago that some moron had "repaired" by removing the regulator. This was operating on the relatively low pressure supplied by the meter in the alley and the burners would blow your eyebrows off if you weren't careful.

GWIZ
09-05-2011, 01:44 AM
I only know some basics.
I cant see it being done without a regulator.

In the link is a temperature/pressure chart for propane.
at 90º F the vapor pressure is 149 psig
at 60º F the vapor pressure is 92 psig.

And the output pressure that I think you require will be fairly low and hard to control without a regulator.

Not knowing the volume you need to pull there is a good chance that the bottle will start frosting and the pressure will drop quite a bit.
be careful you don't freeze the regulator.

http://www.propanecarbs.com/propane.html

A camping trip I went on I frosted up one of the small 16oz bottles using it with a camping stove, the pressure drop was quite a bit.
on a side note there is small propane operated refrigerators.

USMCPOP
09-05-2011, 08:39 AM
From what I can gather, low pressure fixed propane regs are set at 6 ounces. High pressure ones for bigger cookers can be preset at 10 or 20 PSI or the adjustable regs may be 0-30 or 0-60 PSI.

If you have a spare acetylene reg, try that.

tnmike
09-05-2011, 09:45 AM
You are gonna need an adjustable regulator in psi. The one you are trying to use is for a gas grill. Its a fixed output and isnt enough for this type forge.

The Johnson type forges use a LOT of gas.

http://bayouclassicdepot.com/7850_propane_regulator.htm

Something like the one in the above link. Amazon has them. Plan on using at least a 100 lb tank.

milomilo
09-05-2011, 11:29 AM
You are gonna need an adjustable regulator in psi. The one you are trying to use is for a gas grill. Its a fixed output and isnt enough for this type forge.

The Johnson type forges use a LOT of gas.

http://bayouclassicdepot.com/7850_propane_regulator.htm

Something like the one in the above link. Amazon has them. Plan on using at least a 100 lb tank.

Would this (http://www.ebay.com/itm/PROPANE-regulator-HP-adjustable-single-stage-POL-x-1-4-/120761226579?pt=UK_Campervan_Caravan_Accessories&hash=item1c1dee1553) one be satisfactory for my 4 burner forge? It is a little cheaper.

tnmike
09-05-2011, 03:47 PM
The regulator you quoted is in the UK. The price is in euros. I dont think its cheaper. I dont see a gauge on it either. Check the amazon price

http://www.amazon.com/Bayou-Classic-7850-Adjustable-High-Pressure/dp/B000VXEW4G/ref=sr_1_3?ie=UTF8&qid=1315255660&sr=8-3

Its gonna be hard to beat twenty five bucks shipped to you. Im not sure how much pressure it will take to run all four burners. You will have to experiment with the pressure. It will be obvious as to the heat output and flame color. I wouldnt even try to run one on less than a 100 lb bottle. You will get an increase in efficiency if you block the sides off with firebrick.

milomilo
09-05-2011, 05:36 PM
The regulator you quoted is in the UK. The price is in euros. I dont think its cheaper. I dont see a gauge on it either. Check the amazon price

http://www.amazon.com/Bayou-Classic-7850-Adjustable-High-Pressure/dp/B000VXEW4G/ref=sr_1_3?ie=UTF8&qid=1315255660&sr=8-3

Its gonna be hard to beat twenty five bucks shipped to you. Im not sure how much pressure it will take to run all four burners. You will have to experiment with the pressure. It will be obvious as to the heat output and flame color. I wouldnt even try to run one on less than a 100 lb bottle. You will get an increase in efficiency if you block the sides off with firebrick.

Thanks for the info. I had a thought that may or may not be a good idea. Could I use one of my oxygen regulators? They will handle high pressure and they have a wide range of pressure capabilities.

tnmike
09-05-2011, 06:51 PM
An acetylene regulator will work if you change the hose. I would order the one from amazon and call it good. Its made to work with propane. Its UL listed. Its cheap.

bd354
09-05-2011, 07:37 PM
Milo, here in the southeast Agrisupply sells the high pressure adjustable regulators. Maybe Tractor Supply has them also.


http://www.agrisupply.com/high-pressure-adjustable-regulator-valve/p/64484/cn/5400001/

Ironman
09-05-2011, 08:13 PM
I am slowly building a propane forge and have the burners completed. I test fired them and used a red adjustable regulator from a tiger torch. It runs best around 15 psi. I used .035 mig tips for jets.

milomilo
09-05-2011, 09:00 PM
I am slowly building a propane forge and have the burners completed. I test fired them and used a red adjustable regulator from a tiger torch. It runs best around 15 psi. I used .035 mig tips for jets.

My forge has no jets. Just LP into the blower, then through a plenum into the four 1/2 " holes on the refractory into the burn box. I can shut down two of the burners and run it on two burners if I want. I think I will need at least 30 psi to run 4 burners.

milomilo
09-06-2011, 06:58 PM
Welp, got the forge running today. Only ran it on two burners so far. You know how it is when you need a part and you know you have one somewhere. Took me two days but I finally found my adjustable LP pressure regulator.

I messed with the air intake and got the flame to go from yellow to blue. What is the right color? In order to heat evenly, do I space a 1" round up off the bottom of the burn trough about an inch or two so it heats all around?

What is the right technique to put a twists in a 1" square bar? I am guessing a yellow heat is all I need to forge some mild steel into shapes?

Matt Shade
09-06-2011, 08:15 PM
Welp, got the forge running today. Only ran it on two burners so far. You know how it is when you need a part and you know you have one somewhere. Took me two days but I finally found my adjustable LP pressure regulator.

I messed with the air intake and got the flame to go from yellow to blue. What is the right color? In order to heat evenly, do I space a 1" round up off the bottom of the burn trough about an inch or two so it heats all around?

What is the right technique to put a twists in a 1" square bar? I am guessing a yellow heat is all I need to forge some mild steel into shapes?

Blue is better for your flame. You want a neutral to rich mix to reduce oxidation. A yellow flame will scale your parts up.

Depending on what you're doing, having the round in there to rest on can help it heat more evenly. Sometimes if its long skinny stuff you'll have trouble with it sagging if you leave it in there very long and will want to lay it right on the forge floor.

I've mostly twisted smaller stock, but the way I was shown to do it you bring it to a yellow heat and clamp it just to one side of where you want the twist. Slide a pipe over the area to be twisted (not too snug of a fit) and then use a crescent wrench to twist. You will probably want a T handle of some kind for big stock. The pipe lets you keep a consistent spacing if you are twisting multiple pieces and helps keep the piece straight. Other than that its mainly just a matter of twisting at a consistent speed. Takes a little practice and hopefully somebody better than me will give you some tips.

Yellow is actually a little hot for most forging. You can do it on mild steel but it will be very soft and you will have a lot of scale. Taking it just a little past red to a nice orange will probably give you better results most of the time.

milomilo
09-06-2011, 08:34 PM
Blue is better for your flame. You want a neutral to rich mix to reduce oxidation. A yellow flame will scale your parts up.

Depending on what you're doing, having the round in there to rest on can help it heat more evenly. Sometimes if its long skinny stuff you'll have trouble with it sagging if you leave it in there very long and will want to lay it right on the forge floor.

I've mostly twisted smaller stock, but the way I was shown to do it you bring it to a yellow heat and clamp it just to one side of where you want the twist. Slide a pipe over the area to be twisted (not too snug of a fit) and then use a crescent wrench to twist. You will probably want a T handle of some kind for big stock. The pipe lets you keep a consistent spacing if you are twisting multiple pieces and helps keep the piece straight. Other than that its mainly just a matter of twisting at a consistent speed. Takes a little practice and hopefully somebody better than me will give you some tips.


Yellow is actually a little hot for most forging. You can do it on mild steel but it will be very soft and you will have a lot of scale. Taking it just a little past red to a nice orange will probably give you better results most of the time.

Thanks for the tips. I need all I can get.

tnmike
09-06-2011, 09:26 PM
Try and find an old style monkey wrench and weld an extension to the upper jaw. Works great for twists.

milomilo
09-06-2011, 09:59 PM
Try and find an old style monkey wrench and weld an extension to the upper jaw. Works great for twists.

Do you mean like a 90 degree type cresent type wrench that looks like a pipe wrench without the teeth? Can you give me a little more detail on how it is used and what the extension on the upper jaw is for. Don't mean to sound stupid, but I can't quite gather what you are trying to tell me.

tnmike
09-07-2011, 06:16 AM
Yep youve got the wrench right. Some people call them rail road wrenches. The
extension you weld to the top jaw makes the wrench into a t bar so you can twist the square stock. The extension can be flat bar or round stock. Whatever you have.\\

http://www.worthpoint.com/worthopedia/blacksmith-large-hot-twisting-wrench

milomilo
09-07-2011, 07:42 AM
Yep youve got the wrench right. Some people call them rail road wrenches. The
extension you weld to the top jaw makes the wrench into a t bar so you can twist the square stock. The extension can be flat bar or round stock. Whatever you have.\\

http://www.worthpoint.com/worthopedia/blacksmith-large-hot-twisting-wrench

So the extension on the head is for a handle?

seagiant
09-07-2011, 08:10 AM
Hi,
Here's a good tip! Google ABANA and Rocky Mountain Smiths,sorry my computer does not want to copy links. There should be a local ABANA chapter near you!

Charlie C
09-07-2011, 10:53 AM
The tip about using the left handed monkey wrench is a good one, never thought to do that.
Now dang it I have to see if I can find that wrench.

tnmike
09-07-2011, 11:38 AM
The extension is for a handle yes. It allows you to put even pressure on the workpiece while you are twisting it. You cannot get it straight with the wrench alone.

I see those wrenches at every tractor/engine show I go to.

You can use an old pair of vise grips as tongs by the way. You will have to continually hit the quench bucket with them but in a pinch they will work.

I would buy a pair of tongs, practice hammering and then make whatever you need when your skill is there.

milomilo
09-08-2011, 03:35 PM
The extension is for a handle yes. It allows you to put even pressure on the workpiece while you are twisting it. You cannot get it straight with the wrench alone.

I see those wrenches at every tractor/engine show I go to.

You can use an old pair of vise grips as tongs by the way. You will have to continually hit the quench bucket with them but in a pinch they will work.

I would buy a pair of tongs, practice hammering and then make whatever you need when your skill is there.

I've got one that was no use to me until now. Thanks.