Burners 101

[Mikey98118]

I generally prefer fast hard flames out of a burner, But Frosty's "T" burners are an exception to this; with the proper flame nozzle I have seen one of them provide a perfectly hot soft flame. On a practical level, "T" burners provide an excellent flame for positioning top-down on top and mounted at the top of a box forge, where their soft flames can completely combust before impinging on the work.

[chunkynumpty]

Hi  I have been looking at a gas fforge for some months.  Done fair bit of reading and you tube watching.  Tried (quite hard ) to make a burner.     I attempted to use it tonight and Im sad to say it is an epic fail.      

My burner has  1" 1/2" to 3/4"  reducer intake.  A  3/4 to 1" reducer Flare.     A 0.6mm mig tip,   reg varies from 0-2bar.   main 3/4"  nipple is 200mm similar to a few vids out there.

The mig tip is boresight,  and is level with the widest portion of of the reducer flare.     So not tto far in,   or out.   

It wont light in any gas flow rate / pressure.    If I have almost no flow, it will light breifly a blue cloud of flame which self extinquishes with a barely audible puff.  

Any extra gas flow, gives a more green partial light, but wont light.

 

Didnt expect to fail as I did research what to do and how and thought I would be away to glory.

Steve  UK

[chunkynumpty]

I did get this lit but had to light it from the air intake end - with a small blowlamp.    The burner did run, but there were blue flames inside the main nipple/tube,  they were poping and fighting so it is looking like there is not enough flow thru it all.   It wants to back up and a small amount gets into the narrow part of the intake reducer.

I can strip it and add a longer delivery tube to get the tip closer in.

or

I can wind the gas tip out on a thread / nut.

Any takers on which way to try?

[Mikey98118]

To begin with, it is NOT an epic fail; not even kind of poor. You have the fairly rare problem of having built a too hot burner; we simply need to gentle it down some

You did a lot of things right and a couple of things not as good as you could. What you haven't done is a single thing wrong. To begin with, I have been suggesting 2"x3/4" reducer fittings on 3/4" linear burners for about 18 years now. You can look up the first time I made that recommendation on a MIG tip upgrade to a Ron Reil burner on his pages.  However, don't bother changing that on your burner 'cause you are actually inducing too much air already.

What to do now? I have also recommended trying out both .023" MIG tips and .030" tips on 3/4" burners for almost that long; some burners do best with the smaller tip and others need the larger one. Your burner needs an .030" tip at a minimum.

I don't like reducers as flame nozzles because they can't be tuned to find just the right amount of overhang for a given burner. However, let's see how yours works with the right MIG tip before we change anything else.

Congratulations in advance on a fine burner build. So why do I think your burner has turned out to be such a wild child? You used three ribs to connect your gas assembly to the reducer, and you also aimed them like fins, instead of using a flat bar "U" shaped saddle; this arrangement is creating spin in the incoming air as it enters the reducer, rather than after it enters the reducer.

Good job so far!

[KENR2600]

On ‎3‎/‎19‎/‎2018 at 4:29 PM, Mikey98118 said:

You are describing burners with excellent balance. Probably, what you need now is simply to play with them until you become familiar with what it takes to balance them, which we call tuning, where you want them. I would love to see photos of them posted here with all three colors showing. You just described burners that can be changed from reducing (greenish); through neutral (light to medium blue); to heavily oxidizing.

I made some adjustments, and can now turn down and run through a range. I put green thru purple - with the corresponding shot of the flame in pitch black also. The last one shows the twins - with a massive mixing tube and little air to lazy it up and show the balance between the lazy rich flame and the hard blue one on the "tuned" burner.  This is around 7-9 psi on the gauge. I had concerns with flame blow off with a shorter flame holder at 15 psi - but went back to check troubleshooting Reil burners on the ABANA site, and was reminded he runs these - 7 psi or so... in a forge... so, I'm not too concerned with that. Besides, my new nozzles hold up thru 30 anyhow.....

[chunkynumpty]

Hi I did a vid last night but its MP4 hope it works.

 

you can see it cant light.

 

I lit it aiming another burner into the air intake throat .

 

will try 0.8mm tip  when i can.

20180320_233915.mp4

[Buzzkill]

25 minutes ago, chunkynumpty said:

you can see it cant light.

Have you tried different choke positions?  It looks like your choke plate is fully up in the video.  If the main problem is pulling in too much air then you should be able to find a point where you've choked off enough air to get the flame to burn at the tip rather than in the tube, but it will probably require higher pressure than you appeared to be using.  I can't tell from the video or pictures if your choke plate will close all the way or close enough to the end of the reducer to have the desired effect though.

Of course Mike's suggestion of a larger MIG tip should be tried as well (or first) since that would provide a higher gas to air ratio if all other variables remain the same.  A 0.6mm MIG tip is where we would start with a 1/2 inch burner, and a 0.8mm MIG tip is where we would start with a 3/4 inch burner.

[chunkynumpty]

Hi thanks for the feedback.   With the 0.6 it was buzzing and had flame throughout the tube.  I tried a range of pressures but it did the same all over.  Your right about the choke - it runs out of adjust just as its having an effect.

 

I just put a 0.030 on and it lights almost perfect every time.   It  isnt blue now.   The cone is light blue but the surrounding area looked more purple with speckled yellow orange.

 

In the attached vid, I advance the reg pressure to about 1bar and the cone stretches out, just about to detach and blow out, then back to where it starts wanting to self extinguish at the low end. 

Bit more fiddling need I trust.

 

One thing to try is the original tip but located further into the throat?  This may force the mix a little quicker and get it lit at the right end?

 

 

20180321_192527_001.mp4

[KENR2600]

I'll agree with Buzkill - if in fact that choke plate is up all the way, you should be sucking way too much wind to light. My 1/2" pairs were starving for air, a few mods - put the .06 tip down to the throat and blammo... they started sucking wind hard enough I couldn't begin to light them without putting my choke caps nearly closed - even with the extra long flame nozzle... shut that down, lower the psi in, and you should be able to easily light a flame off the end. I think Mike is right - this SHOULD be a wild child burner. The only reason to not be able to light propane is too much velocity to keep it lit. Holding your flame to the end could be tricky with just the screw on reducer, but it SHOULD get you going anyways. Get her lit, then bump up the gas, and whirl your choke around. That .06 may be a bit small - and will INCREASE the VELOCITY of your gas output.

[chunkynumpty]

Nice thanks Ken -  I think  we almost went together there.  I posted about 10 secs before you with an update using the 0.030 (0.8mm tip), please have a look..  Steve

[KENR2600]

5 minutes ago, chunkynumpty said:

Your right about the choke - it runs out of adjust just as its having an effect.

I see now, the shoulder it bumps into at the bottom end is basically at wide open for air, also a prime reason for your purple flames - too much air oxidizing(?) the flame... too little it will run green - just right in blue...  definitely play with your tuning the tip in and out to the throat to find that sweet spot. Mine, I have to cut and clean a new tip to length to change it.

Unfortunately, my computer can't handle the mp4  - it'll come up but only play a frame every 3-4 seconds....

[chunkynumpty]

I can strip it and add a longet threaded tube, this will give the ability to get the tip into the throat more.

It will move the brass cap with the tip in it further into the reducer too - so the choke can then come all the way down.

 

Sounds like a plan, just got to get off the sofa and into my cold garage again!

[KENR2600]

5 minutes ago, chunkynumpty said:

just got to get off the sofa and into my cold garage again!

I hear you. Not sure where you're located - but I can tell you it's been pretty chilly here in NH lately. Throwing some flame around helps a bit...briefly.

 

[Frosty]

A couple things: First, put it in the forge where you're going to use it.  It make a real difference, especially for linear burners. Secondly, Close the choke down a little at a time till it's tuned.

It's well within tuning range. Only change ONE thing at a time, if you try more than one you'll never know what did what or how it relates. Do NOT change the jet even a tiny bit! Not till you've changed the choke and know for SURE that won't solve the issue. If you change both you're just guessing and luck is the only thing that'll get it burning properly.

Frosty The Lucky.

[chunkynumpty]

I just came back in from tweaking in garage,   please take a minute to look at the latest vid.

What do you chaps think of the performance of burner the video?   What doesnt show is the colour range.  I get yellow, green, blue and purple.  This was at  0.5Bar. on the reg clock, long 6mm bore hose.

  I have to say Im VERY new to this, with a total burner fiddling time of less than 1 hour.  So all of your advice is useful and is sound engineering informed know how.

20180321_230557_001_001_001.mp4

[Mikey98118]

All the guys came up with good advice to try.

I would only add to my first advice, that you want to emplyTweeco "T"  series tips, or one of the knock-off series of tips that are tapered and 1-1/2" long. Why? Becuase this will not only give better gas flow, which you may need from a .030" tip but will allow you to move the gas assembly back, so you can try closing the choke plate more.

And again, I think your burner only needs tweaking; not any structural change. We see builders of hot burners ringing their hands during fine-tuning the flame all the time; it's trying to the novice, but your very problems are encouraging signs to us old hands.

[KENR2600]

On ‎3‎/‎1‎/‎2017 at 8:06 PM, Mikey98118 said:

I have never  seen an orange hot flame nozzle on a burner producing secondary flames. Finally, the shape and tint of the secondary flame was all wrong. I have concluded that the video had picked up super heated exhaust gasses, which are invisible to the human eye, and were showing some image into the near I.R. bands.

As I have been tinkering and tuning my burners, I noticed the complete change of colors the camera picks up - but most interestingly, when I was looking at the display screen, and canted it a little so I couldn't see the picture, I COULD see the spectrum of light the screen was picking up. It looked like the flame was at least twice as long as what you could see directly on the screen, which also is a little more than what comes out in the picture. This also applied to total dark. I could see the "heat" rising off the flame end.  It was easily picking up things the eye could not. I thought it nifty when I saw it...

[Mikey98118]

Flame retention nozzles serve three important functions

(A)    By reducing the pressure in front of the mixing tube they help keep the flame from burning back into the mixing tube from the nozzle, as it acts as an ignition chamber for the flame.

(B)    By reducing the pressure behind the flame, it enables the surrounding air (or the slightly higher back pressure of the equipment’s internal “atmosphere” to push against the flame’s expansion pressure, creating a balance that helps keep the flame from being blown away from the burner.

(C)    It has been contended by some that the flame nozzle helps induce air into the mixing tube; possibly because its shape finishes creating a venturi on linear burners. I can’t argue with the reasoning, but I believe the flame is at least contributing to air induction; this is supposition on my part. But linear burners with an (impeller) fan-driven vortex greatly reduce mixing tube pressure without harm; I believe this is because they also support larger diameter flame nozzles, which further reduce pressure in the nozzle area; thus providing some support for the idea of flame induction.

I don't mean this pause to interfere with the ongoing burner discussion; I'm just as interested in as others are.

[Mikey98118]

Could we all get back to ongoing burner discussion; pleas, please with a cherry on top?

[Mikey98118]

The last series of photos show a neutral primary flame with an acceptable amount of secondary flame for use in a forge. Possibly the most likely way to improve it still further is to close the choke plate further. This could increase air spin in this forge design. Or not; it doesn't take much to find out.

[KENR2600]

Photography and video of what the eye sees is pretty tricky it seems. I can get good color of the primary - if I hit the flash. The secondary flame disappears mostly... without flash, the exposure seems too long, and whites and brights show up more so than by the eye. This is especially true it seems of video. There is no white to be seen by the naked eye when shooting the attached video. You can see white and blue, and watch the blue change. What I was seeing, was green off blue primary, and the blue changing to purple as the air was choked out. The only white I could actually see was to come around and look up into the flame nozzle, and it was nearly white there. It is much brighter on video exposure.

P1020931.avi

[KENR2600]

Photos - the white is no flash,  the secondary flame shows more longer than the eye sees - the color is shifted more to blue/purple than the eye sees. The darker photo is flash on. The primary flame becomes more red/blue and the secondary flame nearly disappears. The closer cut, I edited the photo to bring the primary flame as close to true color as I could get it. The secondary flame becomes more visible, yet more translucent than seen by the eye.  The video is super bright and blue/red compared to the naked eye, the secondary flame is much more purple on video - but the extent of it can be seen - plus some you can't. These were a few minutes after lighting, on a lower pressure showing about 6 psi on the gauge.

P1020935.avi

[Mikey98118]

The second photo shows what I regard as a perfect flame-- if that is what your eyes see.

The third photo shows what is the best flame in a forge because a minor amount of secondary flame will help to keep down scaling on the workpiece while it is in a forge--if that is what your eyes see.

Of interest to you is that the flames in bost photos show the burner on the right to be superior to the burner on the left.

Of interest to all of us is that the second photo shows burners running at the top of the neutral range; just beyond this point flames start into the oxidizing range.

The third photo shows burners running at just within the neutral range; just below this point, flames start into the reducing range.

[KENR2600]

I figure they are about forge ready... I've tinkered the jets, nozzles, tubes, and just about everything else to overcome their known shortcomings. They seem to be suitable - nearly satisfactory (which for a fiddly nit-picker is hard to obtain). Now they need a forge atmosphere to work in....the next hurdle. Of all the odds and ends I've got around - refractories aren't among them. I've got a 15" round shell. I want to take the bottom 3" up and level-ish floor it. I'm not sure what to do with that null space at the bottom... but that's a whole different discussion, tangentally associated with the burners...Should I bring that over to Forges101 - or start it as my own New Topic? 

BTW... I will show my burner construction, but DON'T recommend anyone try to follow it. The instructions on how to build one properly will be MUCH easier to get right. These are pretty much made on a question of - Can I do it with what I've got? Which took way more work tinkering and modifying than just following the Reil plan as drawn. Nevertheless, I love a challenge, and you HAVE to learn the whys of the hows to see what's going on. 

[Mikey98118]

  From one fiddly nit-picker to another; "ain't it just so!"

Your choice of shell is going to cause you some problems too, but they can be turned to your advantage...in the end. Most five-gallon propane cylinders will end up with a 9" inside diameter interior before the floor is added to two 1" thick layers of ceramic blanket. The Adding a floor doesn't shrink the space in there all that much because it is only taking room from a fairly narrow area. This method has generally worked out well in five-gallon tunnel forges, when heated with two 1/2"  or one 3/4" burner (with your kind of very hot flame). However, the usual thickness of insulation should end up with an 11" diameter in your forge; unless you raise its floor so high that the interior becomes a "D" shape, you aren't going to heat the forge sufficiently.

You can't just pile layer after layer of blanket under a layer of refractory or a high alumina kiln shelf to raise the floor that high, and expect it to properly support the floor. You need to rigidize the blanket, and then employ K26 firebricks from eBay between it and the floor, or else trap Perlite from the garden department of a big box hardware store under the blanket to raise and flatten the floor area, and use a rigidized blanket layer to keep the Perlite in place.

If you don't want all that hassle, free used propane cylinders are easily acquired from your nearest U-haul store that sells propane...