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Ok so I’ve made a few changes, upgrades really, to the burner since my last post. I’ve pretty much revamped the whole thing hence the new instructable.

The basic concept behind this burner was to make the nozzle interchangeable so that the unit could work as both a forge burner and a foundry burner.

Essentially the unit breaks down into three parts: the fan mount (I used the one from my other burner), the mixing chamber, and the nozzle. When connecting all the peace be sure to use pipe dope or plumbers tape with the exception of the nozzle and fan attachment areas, as these will see the most ware from change out. if you choose to make the connection more permanent go ahead and use the dope or the tape.

Step 1: Parts

Similar to my other post you could find most of the parts at your local hardware store, such as HomeDepot or Lowes. The only thing you might have difficulty getting is a fan. I used the same fan from my other burner, but looking back you could probably get away with a hair dryer with the heating element removed.

Aside from a fan and a way to mount it, again see my other post. You’ll need the following

Mixing chamber
2”x10” nipple
2” coupling
½”@90 black elbow
2 - ½”x6” black nipple
½”-¼” reducer (we used brass)

Nozzle
2”-1 ½” reducer
1 ½”x18” nipple
1 ½”coupling
1 ½”x6” nipple

Step 2: Assembly

Fan mount
Again I used the fan from a previous burner, of which the resulting connection piece is a 2"x6" nipple. regardless of what fan you use or how you mount it the rest of the unit revolves around it connecting to the mixing chamber (this tutorial uses a 2" diameter pipe).

Mixing chamber
Be sure to use pipe dope or tape on all these connections. Don’t want any gas leaks.
Half way down the 10” nipple (so 5”) drill a big enough for one of the ½” black nipple pipe to fit through.
Connect the 90 to one of the black nipple pipes; hold the pipe in the center of the 2” pipe with the 90 just below the hole.
Screw the other ½” pipe into the other end of the 90; be sure to put it through the hole.
Weld the pipe in place try to keep it as centered as possible.
Attach the ½”-¼” reducer to the end of the pipe in the 2” pipe.
Attach the coupling to the opposite end of the chamber for the fan connection.

Nozzle
*As stated in my other instructable my foundry inlet is 1 ½” please adjust the nozzle size to fit your own.
Connect the 2”-1 ½” reducer to the 1 ½”x18” nipple
Attach the 1 ½”cuppling to the 1 ½”x18” nipple
Attach the 1 ½”x6” nipple to the 1 ½”cuppling
*As the burner gets used they will eventually deteriorate hence the coupling, it allows for an interchangeable end piece.

Step 3: Last Step

The last piece of information you need is how to connect your gas line. For me, I have a ¾" gas line that I connect to using a flex line (the kind use for stoves and dryers) with an anti-blow back valve. The flex line connects to a ¾" black pipe with a ball joint on the other end. After the valve there's a ¾"-½” reducer which connects to the ½” blackpipe welded to the mixing chamber.

Step 4: Use

Remember safety first. Have fun melting metal or forging something new!

Step 5: Update...

Sorry for the ridiculously long wait for the burner tips but life kind of got in the way...anyways.

I'm separated the different tips as extra step so I could explain what I use each one for.

Step 6: Forging Tip

My first forge was little more than a metal box that held 9"x4.5" fire bricks. after some rudimentary testing I came up with this design.

The 2"-1" reduction cavitates the air flow from the blower to promoting a better fuel mixture. the mixture then passes through the 1" pipe and out through the inner nozzle bypassing the holes in the outer nozzle. The inner nozzle is connected by a few threads that were left on the 1"-1.5" bell reducer (alternatively you could weld the bell to a longer section of pipe, so long as they bypassed the outer nozzle holes).

The outer nozzle consist of a 1.5"x8" nipple and a 1"-1.5" bell reducer with 6 (3/8") holes drilled in, respectively. The air flow from the holes (due to the negative pressure caused by the inner nozzle) supplement the some of amount lost from the initial reduction, producing a hotter flame.

With this burner I was able to get to low forge welding heat, after the forge warmed up.

Step 7: Foundry Tip

As I have stated in my previous steps the inlet for my foundry mates to a 1.5" pipe, so subsequently the burner is reduced to that size.

In essence the nozzle is little more than a 1.5" pipe, with a 2" reducer on one end and a coupling for a replacement tip on the other.

Step 8: New Forge Burner

I made a new forge a while ago and with that was a need for a new burner...all this in pursuit of forge welding heat (of which I achieved).

The design is pretty straight forward for this one, though a lot more in depth. Its a brick, with a grid of holes, attached to a mixing chamber/manifold, and welded to a connecting pipe. This style lends it's self to a lot of variety, so make whatever works best for you.

For this one I used a 3" pipe, cut it in half, and made a trough by adding half circles to cap the ends. A hole was cut in the middle and the trough was welded to a 2"x8" nipple. Two 3/8" lag bolts were welded to the inside to hold the brick on to the manifold.

Create a box with a floor plate/board. Drill a grid of peg holes large enough to fit crayons or birthday candles (these will be burned out to create the holes in the brick). Cast the refractory into the box, set the manifold into the brick and allow 1 week to cure. Remove from mold, and burn out candles/crayons.

Step 9: Update 2

Some recent tweaks to the assembly as a whole.

  1. Added a 2" gate valve between the blower and the gas inlet.
  2. Replace the blower with a 100 CFM fan that has a 2" outlet.
<p>Thank you, I appreciate the info. Lot of stuff out there on propane, but this is the only instruction on natural gas I have been able to find. I made up three nice burners like I have made for propane and all I got was a lazy curled up flame. I found an old variable speed forge fan and will try out a 1/4&quot; orifice in a pipe quick and dirty and see what happens.</p>
Yeah, that was my experience when i was trying to build mine. Figured others could learn from my xp, as poor as it was...Good luck building your. If makes any difference I'm able to get up to forge welding best with it.
<p>So, you increased the gas orifice hole size from 1/8&quot; to 1/4&quot; ? I have 1/8&quot; on mine now and it does not work well and I was just thinking about increasing it to 1/4&quot;. How long of flame does that give you?</p>
About 7&quot;
<p>so for a foundry heat source do you actually need a fan or will just the Venturi effect work?</p>
Sorry for the late rely, I'm sure you've got the info you need but the gas pressure is not enough to cause a Venturi, at least in my experience.
<p>How about those burner tip images!!??</p>
<p>Updated...</p>
good post. i need more images for biogas burner for those burner who make 30 ltr of later hot in 4 min. <br>thanks
I'll upload images of the different nozzles as soon as I get a chance to take some.

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