How to Build a Gas Forge Burner

Intro: How to Build a Gas Forge Burner

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.

Comments

[heroics]

How did you connect the brass pipe to the propane?

[JadenT11]

I made this but couldn't make a flare so I tried without it and a bell reducer but it doesn't blow(not enough air in the mixture) its too weak of a flame, it is primarily blue but not as good as his. Any ideas?

[ArcherKN24]

If the flame color is blue, too little air is not likely the problem. Lacking air would cause a rich flame and would look yellow. As you posted this 4 years ago, you have probably figured it out on your own already. My bet would be that the regulator you are using was from a standard grill (fairly low psi), and thus the gas was just not coming out as fast.

[aclark17]

I'm just gathering information on all of this but there was that Venturi effect that's a fundamental principle for how these work, you need a narrow section between intake and tip to decrease pressure and increase velocity of the fluid (gas), so if I had to guess, I would say you would benefit having more of a choke point to get more velocity. Anyone that knows more than I do wanna verify for me?

[Oldprophet]

Do you know how many BTU's this burner puts out?

[Gooru]

Depends...
The orifice produced by a #57 bit will inject enough gas to produce about 13,000 BTU with a standard 11" WC regulator like you find on a BBQ grill. If you can acquire an adjustable regulator (try a welding supply shop), 10 PSI will put you well past 70,000 BTU.

[Oldprophet]

yeah, most BBQ regs only go up to 7 psi, but i found a high pressure hose and reg that went up to 20psi, they are on the home depot site. Also had a hard time finding such a small bit like a #57, but you can also pick up a set of dremel micro bits from home depot, one of which is almost the exact size of a #57. burners work great! guessing my burners put out around 200k BTU

[DemonMaker]

how much does it cost to build one?

[slanwar]

I went to Lowes and after I got everything besides the regulator was more than $40 so I end up returning everything and bought one from ebay for $55 with a 20 psi regulator included.

[tincup92]

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.

[AirplaneM2]

Soak your galvanized parts in vinegar for 4 days and the zinc coating will be gone.

[BishCo]

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

[Dillon.means.Perfection]

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?

[BlacktagMi]

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!

[BrandonL158]

Drink 2 glasses of milk and let it ride lol

[720545]

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.

[MitchG11]

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

[JadenT11]

how did the 1/4 work?

[Bverysharp]

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)

[AirplaneM2]

I made two for a forge. I only added a intake valve on them.