burner flame

B

bjalongi

Joined
Oct 23, 2006
Messages
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I lit up my new burner today. Darn thing shoots out a big blue flame, and roars like crazy.

I built it with 3/4" black iron pipe, 7" long. The rest of the fittings were lying around my shop. I cut the swivel orifice fitting off a 0-10psi turkey fryer regulator/hose and replaced it with a brass barb. I've constructed two different cones thus far. The long and narrow cone seems to work the best. I used a galvanized elbow, because it's all I had. I'm not sure if zinc plated stuff is bad around propane gas piping.

There is a flame inside the pipe, though. Isn't the flame supposed to be pretty much isolated to the cone? You can see a blue dot in the intake hole on top of the pipe.

What's your thoughts on this? Is this a time bomb? I'm concerned about the whole system overheating.





Thanks for looking.
BJ
 
it is supposed to roar like that. its supposed to sound like a jet engine. im not sure about the zinc plated parts but i know others here are. looks good tho.
 
Way back in high school, my shop teacher told us never to cut galvanized steel with a torch... IIRC the zinc burns off and the fumes are not good for you.
 
GibsonFan said:
IIRC the zinc burns off and the fumes are not good for you.
Click to expand...



WWAAAAAAYYYYYYYY understated!

Zinc fumes are TOXIC!!!! Do a quick search on this forum alone and you'll find we've lost too many knifemakers to this!

BE CAREFUL!
 
heed those warnings!!!!! dont want to lose any more knifemakers. just use brass or steel or even black pipe fittings.
 
Good job! Now, to get that flame out of the burner you need to increase pressure. The flame will pop outta there and sound really smooth. Once you've got the flame burning on the outside, you'll be able to regulate it.
The position of your galvanized elbow will probably prevent it from getting hot and turning you into a canary in the coal mine, but be on the safe side and replace it as soon as you can (don't use it for extended forge sessions till you do). Good luck w/ the build!
-Mark
 
I'm aware of the zinc fume danger. My concern had to do more with the gas' chemical properties and the zinc. I can probably find the composition of zinc plating on the internet and balance an equation with propane to find out. But I'm probably going to find that it's not an issue.

Polish Avenger, I used a 1/8" brass pipe for the purpose of heat reduction, so I don't think the galvanized elbow will get hot enough to burn. I'll replace it though; for one, it would make it look like less of home spun gizmo.

I'm not sure if any of you looked at the larger pics of the thumbnails, but I drilled two 3/8" holes in the black iron pipe. I started with one, but it blew out too easily. With two holes the flame intensity really jumped. You can also see a little blue in the second hole.

Should I replace the black iron pipe, or will these holes be ok if I pipe in forced air from the back?

Currently, I haven't ran it continuously for more than two minutes. The cone gets red hot, which I expected, and the main pipe gets dang hot at the end. How hot do your burner pipes get? I assume they're less hot with forced air, because it pushes the flame away from the end, slightly.

Thanks guys. You're a big help.
BJ
 
Looks good but like you said too blue.

Add more gass, i.e. more pressure or larger orfice. More pressure may such more air and the mix might stay basically the same. like Polish said more pressure will push the flame out the end.

Reduce the oxigen (air) partially cover your air vents (use something that can take the temperature)

Vaporized galvanized is bad juju. The zink fumes will first ruin your sense of smell (permanently) then other nasty things happen. Copper oxide from overheated copper is also bad, very bad.

Jim Arbuckle
 
Oh, and are their disagvantages to using my air compressor to supply forced air? I could install an oil water seperator at the input to prevent oil droplets from being induced into the system. This intake air flow could be easily controled with a ball valve or small regulator.

I haven't heard many people talk about this option, as most use electric fans.
 
Damneng,

The pictures were taken at ~3/4 regulator capacity. Max is 10 psi, and when it's cranked all the way up, the flame inside stays the same. I'll have to try the forced air route tonight and let you guys know what the outcome is.

I made an air intake control out of a piece of sheet metal. I can slide it back and forth on the pipe to close off or open the air holes. May come in handy for when I apply forced air.
 
My burner is pretty much the same. My pipe is 13/16 ID, my air holes are 3/8, but I use 3 of them (six since there are 3 on both sides). I don't use a flare. Once I start the burner at a low pressure, I give the regulator a crank and the flame exits the burner tube and stays there, even to as low as 1psi. I can reliably pressurize to 15psi, quickly reaching forge temp of 2000 degrees. Heat is no problem as it never reaches even the shut-off valve which is directly mounted to my brass jet.
-Mark
 
perhaps my jet hole is too big. I used a #57 drill bit. I could make another delivery tube with a smaller hole.
 
Bear in mind as you "optimize" your burner that performance standalone versus in the forge will differ.
 
#57 hole should be just fine, that's what I used. Have you played around with the alignment of the jet? Needs to be super straight down the burner tube.

Fitzo's right about that. The backpressure? of the forge will have an effect on the burner performance. Am I using the right term, Fitzo?

-Mark
 
The backpressure, yes. Also the chaotic influences on the flame from being in an "enclosed" environment both geometircally and thermally. Further, if you have a forge built so the burner tucks into another tube that's welded to the forge, everything changes again because it will typically lengthen your "flare".

My point is to not necessarily expect the same performance in and out of the fforge, so do the tuning attached to the forge.
 
I'm almost done with the forge. So, I'll let you guys know what the outcomes were after I've tried the whole set up.

Thanks everyone. All good info.

BJ
 
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