How to Build a Gas Forge Burner

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First and Foremost, This burner was designed by Mr. Ron Reil. All credit for this design goes to him. Visit Ron Reil’s page at the link below:

http://ronreil.abana.org/design1.shtml

Also, Fire is Hot. A burner like this puts out a significant amount of heat and using such a device improperly is likely to cause you injury and/or property damage. I suggest you use good safety procedures building and operating this burner, BUT AM NOT RESPONSIBLE FOR YOUR ACTIONS OR CHOICES NOR AM I RESPONSIBLE FOR ANY DAMAGE OR INJURY THAT MAY RESULT FROM YOU BUILDING AND USING THIS DEVICE.

There are countless designs for forge burners and furnace burners online. I like this one because it is simple to construct, and the materials are easily obtainable from most hardware stores.

This burner was built for this small forge. The forge is small enough that I can run the burner at under 5 psi and keep the interior at a good working temperature.However, this burner design does work well in larger forges, many large forges even use multiple burners.

In order to build this forge burner, You will need a drill, a set of bits, and a couple of files. If you don’t have a tap to install the set screws, there is an alternate method that I will address at the end of this article. Also, in order to forge the flare for this burner, you will need a functional forge already, or another heat source. If this is your first forge, there is obviously going to be a problem here. The alternate method for this too will be at the end of the article.

Also, it is important to note that you will need a gas regulator to run this burner. Simply running a hose from the burner assembly to your propane tank is not going to cut it. Regulators can be purchased locally at welding supply stores.


Step 1: TOOLS AND MATERIALS


MATERIALS

The main burner assembly is made from black iron pipe fittings. I bought all of these off the shelf at Lowe’s. DO NOT use galvanized fittings as they will produce toxic fumes when heated.

The brass fittings are all 1/8″. The 4″ nipple, coupler and end cap on the left make up the segment that is installed into the intake of the burner. The rest of the fittings serve to distance the hose connection from the heat of the burner, and can be constructed in any configuration you want.

Step 2: BURNER INTAKE 1

BURNER INTAKE

The first task is to fit the 4″ brass nipple perpendicularly through the wide opening of the bell reducer. For the burner to perform optimally, the tube needs to be centered through the intake. It doesn’t have the be perfect, but it does need to be close. I marked out a center line on the face of the reducer using a carpenter’s square and a combination square as shown in the picture.

After marking the center line on the face of the burner intake (bell reducer), extend the lines down the side of the reducer. Then place the 1/8″ brass nipple against the wide rim of the reducer and mark across the center line where its approximate center is. Transfer this line to the opposite side with the combination square.

Step 3: BURNER INTAKE 2

Before drilling the hole for the 1’8″ brass nipple, I align the center marks with the jaws of the vice to help me in orienting the drill bit. First drill a pilot hole through the “X” that we marked on the side of the reducer. Then I drill through with a 3/8″ bit.

Use a round file to allow the brass nipple to fit through both holes.


Step 4: BURNER INTAKE 3


Now that the gas tube fits through the intake of the burner, we need to find a way to secure it into position. During usage, the orifice must be pointing directly down the burner tube to burn correctly. To do this, we will install a set screw to keep the tube from rotating.

If you have never used a set screw before, the process consists of drilling a hole, then using a tap to cut threads into the sides of the hole so that the appropriate screw will fit inside.

The hole is easy enough to drill by hand, just pay attention to the angle you are drilling through the wall of the reducer. It is a slight inward angle toward the smaller opening of the reducer. I used a size 8/32 tap/screw which is drilled with a 9/64″ drill bit. You can go smaller than this if you want, but I would suggest you do not go any larger, as it would be easier to cut through the wall of the reducer.

Step 5: ORIFICE

ORIFICE

The burner orifice is drilled with a #57 drill bit. As with the positioning of the gas tube, It is important that the hole is centered. I mark a line down the length of the 4″ nipple to help me gauge by eye where the center is. Smaller drill bits are pretty fragile, so if you are drilling by hand like I am, be careful not to apply too much force. Just let the bit do the work.

IMPORTANT: Make sure that the orifice is pointed down the burner tube (small end of reducer) before using the burner. I had mine position upward with the setscrew tightened because it was easier to hold it in the vice. MAKE SURE THAT YOU POINT THE ORIFICE DOWN THE BURNER TUBE BEFORE USAGE.

Step 6: Flare


FLARE

With the help of the funnel shaped burner intake, the mirrored funnel of the flare at the burner’s tip helps to create the vacuum effect known as “venturi”.

The flare is made from a 3″ segment of 1″pipe that slides over the end of the 3/4″ burner tube. After heating the 3″ segment to a red heat, I hammer the rim of the pipe against a piece of round bar, rotating the pipe as I work. The flare should expand out to around 1 1/2″ at the opening. I recommend putting a set screw in flare as well, to provide a wider range of adjustments for your burner.

Step 7: Assembly

Assembly

To orient the orifice, I took my #57 bit and inserted it, shank first, into the hole. Using the bit as a pointer, I directed it out of the SMALL end of the reducer (down the burner tube) and centered it as well as I could before tightening the set screw. It may take some more adjusting, but that is a good place to start.

As I said before, the fixtures coming off off the 4″ brass nipple (gas tube) serve primarily to distance the rubber gas hose from the heat of the burner and forge, so you can use whatever configuration you want. The last fitting on the brass assembly is a 1/8″ to 1/4″ bushing which attaches to a LP gas hose which attaches to a regulator running off a 20lb propane tank.

Conclusion.

I do not claim to be an expert on much of anything, but specifically on forges. My authority on these subjects is that I have successfully done what I am talking about, and I am willing to take the time to document my experience and produce article, videos, and instructions to the best of my ability so that others can overcome obstacles that I have met. I am always open to advice from the many, many folks who know how to do this stuff better than I do, and I am always happy to give advice to anyone who asks.

So, for more honest to goodness instruction on forges, knifemaking, and metalworking, Check out my website at the link below:

www.makingcustomknives.com

Thanks for reading.

Step 8: Alternatives - Set Screws

ALTERNATIVES

In section I will talk about work-arounds for certain parts of this forge burner. The first is the set screw. If you do not have a tap set, you need to use another method to secure the gas tube. To substitute the setscrew, you can use the threaded end of a 1″ pipe segment screwed into the intake (bell reducer). Just tighten down the 1″ pipe against the tube to keep it in place. The disadvantage to this is that it narrows the intake, and therefore decreases the amount of air in the fuel mixture. This inst necessarily a bad thing, just something to remember.

Step 9: Alternatives - Forged Flare


Next, in order to forge the flare, you will need to already have a working forge. The alternative to the forged flare, is to simply not forge the flare. Using a 3″ piece of 1″ pipe over the burner tube will create the vacuum or “venturi” effect when. The “disadvantage is the same as before, it will not draw quite as much oxygen into the mix.

4 People Made This Project!

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122 Discussions

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britbano

2 years ago

Thank you for the response, i figured it out today. Got a 10 psi camping regulator from academy and now it works great!!

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WilliamM474britbano

Reply 6 hours ago

I know this is 3 years old, but I will answer this for all of those who follow. If you do not run a 30 PSI regulator, then you are not in the ballpark for these burners. Some setups even run 60 PSI regulators, most of the time that is with the larger 30 gallon or 100 gallon tanks if you buy for RVs. Forced air dot-dot. Just like supercharging a car engine dot-dot. Will use more fuel in the same instance of time but will create more power which in this case is heat. All it takes is an air compressor tuned down with a pressure regulator on it tunes down to about 20 psi and you will have more heat than you know what to do with. Technically at 14.7 PSI which equals one bar of pressure, you are doubling the atmospheric pressure. This means in theory without any other restrictions you should be able to make twice the amount of power.

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Jungoica

4 days ago

Wondering if it would be good to use gas tape on the brass joins?

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CoCZ1

4 weeks ago

Is the #57 bit the proper orifice to create maximum BTU from this set up?

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DemonMaker

Question 2 months ago

how much does it cost to build one?

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flemingpaul8

4 months ago on Step 7

So obviously the flared end of the burner is the end that gets welded to theforge, but does it sit on top of the forge and get welding making the hole drilled in the forge the same size as the flared end of the burner? Or does the flared end of the burner insert inside the forge at a certain depth then get welded?

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flemingpaul8

4 months ago on Step 6

What is the material and measurements of the burner tube?

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arashikage13

Question 4 months ago

How big of an area does this burner usually heat i want to make a fairly large forge and im willing to do multiple burners i just need to know how far apart they can be and still get an even heat

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tincup92

2 years ago

Can galv pipe be use for the just the part going through the bell. the piece that feeds the gas. Having a hard time finding 1/8 brass around here. plan to run 1/4 galv for that part.

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BishCotincup92

Reply 2 years ago

NO!! Galvanized pipe should not be heated. It gives off toxic fumes.

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wouldn't it be ok if it is done in open air, I mean isn't it just small quantities of zinc that will be released?

I thought the same thing that being outside would be enough. This is also what my friend thought. Unbeknownst to him He welded on galvanized & it swelled his eyes shut lol
In all seriousness, his eyes were swollen shut for 6 hours!

From what I understand even a small amount of zinc will give you something called metal fume fever. Take all precautions to avoid this, it really sucks.

This is a for real No, not just a bad idea No. I wouldn't want to mess with zinc smoke/fumes in any quantities. http://www.anvilfire.com/iForge/tutor.php?lesson=safety3/demo

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Bverysharptincup92

Reply 2 years ago

If you can't get black pipe, you can throw the gal fittings into acid (even vinegar) and it will eat the zinc off. Once it stops bubbling, the zinc is gone, and heating should present no problems. (The flare at the gas injection end should never get hot enough to cause zinc fumes, due to the air flowing over it and being a long way from the flame)

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MikeAlmogy

1 year ago

Hello.

Will this burner work with butane gas instead of propane? where i live propane is not that common. Thanks, Mike

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harlyquinMikeAlmogy

Reply 1 year ago

that will change your fuel/air ratios a little, and maybe the drilled orifice. I'll bet they are similar enough to just trial-and-error until you get a working fuel air mixture.
propane is c3h8, butane c4h10. The propane will want 5 O2 per molecule, where the butane will want ~7.5 O2 per molecule...
I'm not sure how this will scale up to this project, but I think the ratio is the same: you'll need 50% more oxygen to get a clean burn using Butane...

Please step in and correct me, someone, I am going off of Chem 1010 level knowledge from about 7 years ago...

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harlyquinharlyquin

Reply 1 year ago

Overall, I'm sure you just need to turn the pressure regulator down. Maybe using at 3.5 PSI (or .24 BAR) instead of 5 PSI (.35 BAR) ?