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Home made venturi burner


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JJ,

 

Appears fine, but I thought to mention and you probably would know that it may seem to perform very differently in a forge. I'd stick it in your forge and see if it performs like you hope. If it comes up just a tad short, you might consider a flare from one of the forge component vendors.

 

Bet it'll work just fine, Craig

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I would like to see the rest of the burner with the spec's ie: the orifice size and gas pressure. I take my blower forge to hammer-in's where there is no power occasionally. I have been using an inverter and a battery from my camper which is good for about 10 hours of forging, but I like to keep my options open.

 

Mike Johnston

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Mike I will take pics if you want but I can describe it too

it is a 1.5" bell down to a 3/4" pipe the pipe is 8"

the nozzle is a 1" bell that I hammered to a flair. I did this by putting a ball peen head in a vice and using the ball like a steak tool.

the 1.5" bell is drilled on one side to .5" and has a .5" brass pipe with 2 male ends. The end inside has a copper elbow that is .5" female on one side and 1/4" female on the other. The 1/4" has a mig welder tip in it I think it is .043 for the orifice.

the other end of the .5" copper pipe attaches to my propane line but you can reduce it to 3/8" which I think is another option of hose fitting size for propane.

I drilled a small hole and tapped it to 10-24 from the back of the 1.5" bell and that is where my set screw goes in and holds the gas pipe in place.

If you want pics let me know.

JJ

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Looks good JJ. My only question would be how hot you could run it without starving it for air. In the picture it doesn't look like there is much room around the jet for air to pass in. Could be the angle though. Nice design though, I like it.

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I can see there is some room between the elbow/jet and the bell. If you can't get the heat you are looking for out of the burner the way it is, I would suggest removing the elbow from the brass tube, capping the tube and drilling an orifice hole in the side of the tube so that it would center in the bell facing the burner tube. You would never starve the burner for air and the heat would only be dependent on the gas pressure.

 

Looks clean and simple though. I will have to build one tonight.

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The other one I made was drilled and tapped.

I ended the 1/2 pipe with a square cap so I had a flat to drill into.

So if I need to I can swap them.

Mike please post your result, I'd like to see what you come up with and how it works.

Especially if you put it in the forge.

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Looks pretty good to to me, with the caveat that flame color is always different in photos.

 

I'd strongly recommend you get a couple of MIG tips in the next 2 sizes down and rig up some form of adjustable air restrictor on the air inlet, though.

 

The central cone is where the primary air (the air that gets drawn in at the Venturi) is burning with the gas. The outer, bushy, flame is where the excess gas mixes with secondary (ambient) air and completes the burn.

 

When you stick it in a forge, with nowhere for the secondary air to get in, the bushy part of the flame will become the Dragons Breath, only mixing with the air it needs once it leavs the mouth of the forge.

 

You currently have no means of reducing the air, and seem to have a rich flame already. It may do what you need it to do right off the bat, but if it doesn't, a smaller gas jet will lean off the burn and almost certainly raise the temperature. I know the intuitive thing is "more gas = hotter", but it doesn't always work like that.

 

Once you've got the biggest jet just consistent with getting the forge too hot, you can use the air restrictor to tune the temperature. Reducing the air will reduce the temperature and increase the dragon's breath.

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Hey Tim, thanks for the feedback.

The nice thing about this design is that you can use the set screw to lock down both the gas pipe and a sheet metal disk that can be slid over the air inlet in a circular motion.

I will grab some of the smaller tips.

Thanks,

JJ

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