I cannot get a neutral flame on my oxy/acetylene setup no matter where I set the regulator pressures.


Last year I purchased a small Oxy/acetylene kit from Praxair. The type with the MC sized aetylene bottle and victor torch. My desire was to produce weld sculpture using 1/8 thru 1/4 inch steel rod. However after burning thru much rod and many tanks of oxy/acetylene I quit in frustration. There are no colleges locally offering Oxy/acetylene training. I figured I just didn't know what I was doing which is still probly true.

After much reading and youtube videos I picked the torch up again this past month. I set everything as I had seen and read but the flame I got looked nothing like the ones on any of the vids or those described in any literature. I keep getting a blue white cone kinda sharp looking, with a lead flame being yellow orange. I tried various pressures from the one I had been using 5 psi oxy, 5 psi acetylene but to no avail. The tip I'm using is an "0" size.

I thought there might be something wrong with the torch mix chamber so I drove an hour to the nearest big city where there was a torch repair person. He put the torch on his system and pulled a neutral flame right away. He shut down and asked me to light the torch as he wanted to observe my method. I did so and got the neutral flame right away. He seemed satisfied with my method. He then asked me about my tank pressures and when I told him 5 & 5 psi he said your oxygen is not high enough. He then took the hose off the oxygen side of the torch and showed me a little foot valve that required pressure to move and he said there is a certain amount of back pressure to overcome thru the backflash arrestor as well. He suggested that I up my oxy cylinder pressure to 20 or 25 psi and see if this helped. He suggested if it did not I may have a faulty regulator on either side.

I went home and tried it and again to no avail, The same color flame is produced no matter what I do. It cuts off rod nicely

All I want to do is make art but I'm about ready to jump out a window. Could the regulator not be sensitive enough. Any help would be Appreciated. Goin crazy in Canada!!

johndach's picture

gas mix problems

When you took the torch to the city, did you have your regulators too?? If not, only the torch was checked, I would DEFINITELY look at the potential of one of the regulators is what is giving you the problem. The regulators are the most likely thing to go haywire.

John Dach
web site: http://www.MLCE.net and ctmandalas.com

Rich Waugh's picture

I'm going to go one step

I agree with your torch man that 5/5 is too low a pressure for the oxy. I'd go with somewhere between 15-25 psi on the oxy; it isn't hyper critical. He is correct that some flashback arrestors require a certain amount of gas pressure to overcome their internal check valves, and it is also possible that your torch handle has check valves built into it as well - not real likely, but possible.

You should definitely get the regulators checked as John suggests, but I'm going to go one step further yet. Take the whole works with you to the torch repair guy - torch, hose, regulators and cylinders. Yeah, I know it's a hassle, but your flame description sounds like you either have a faulty regulator (or two) or your cylinders are not filled with pure gases, or possibly contaminated.

The "yellow flame" almost sounds like oxy/propane, rather than oxy/acetylene, and that would give you fits trying to weld, though it would cut okay.

If the torch will work properly on another regulator/cylinder/hose setup, then the torch is fine and your technique sounds fine as well. Something else must be amiss and you really should get it checked out by a professional before you frustrate yourself further or perhaps damage either yourself or the equipment.

It sounds as though you've found a torch man who knows what he's doing and is inclined to be helpful. If I were you, I'd take the whole rig to him, after a quick stop at the local convenience store to grab a six-pack of Molsen's finest or some such as a "thank you." Can't hurt - if you don't drink it all yourself on the drive over there (grin).

SAFETY NOTE: Do not transport those cylinders in the riders compartment of your vehicle. In the back of a pickup is safe, provided they're properly secured from tipping over or rolling around if transported horizontally. If you transport the acetylene cylinder on its side, it should stand vertically for a half hour before using, to let the acetone settle down to the bottom again..

Let us know how it works out for you.


visitor's picture

neutral flame!

Thanks for your response's. Most appreciate. I think your right I'm going to take the whole kit and kaboodle in and have someone who knows troubleshoot it.
Thanks again. Great group glad I joined.

visitor's picture

Setting Flame Advice

This was posted on the Hobart Weld Talk site. Might help.

Balancing Gases In OAW
By M R Tebo - C. 2005

Back in the” old days”, before the widespread use of check valves and flashback arrestors, beginners were always taught to balance gases. This is a procedure I still use today, not only because of safety, but because it is a good way to check on the current condition of your equipment, and guarantees the correct setting with any tip size or regulator gauge peculiarity. With a little practice, it only takes a minute, and accurately gives you the proper setting with any make of equipment, with the max. and min. of the heat range of any tip. The instructions I usually give an OAW beginner are below.

With both bottles on, and regulator adjusting screws turned out (“off” position), turn the acetylene torch valve wide-open (3 half turns is usually enough). Then, turn your acetylene regulator adjusting screw in until gas starts to flow and light the torch. Continue to turn the adjusting screw in until the flame just blows away from the tip, then back off the screw until the flame just returns to the tip. Your acetylene pressure is now set for that tip.

Then , open the oxygen torch valve wide-open (3 half turns) and slowly begin to turn your oxygen regulator adjusting screw in until you you have a blue feather extending from a blue cone at the tip. Continue to add oxygen until the feather just disappears into the inner cone, giving you a neutral flame. You now have the torch set for maximum heat for that tip. (Wiggle both torch valves at this point to make sure you have them wide-open: if you do the flame will not change)

Finally, turn your oxygen torch valve off. Then, close your acetylene torch valve until the yellow flame starts to produce smoke, and immediately open it just so it is not smoking. Slowly open your oxygen torch valve until you again have a neutral flame , and you now have the minimum flame you can use on that tip without backfires.

This seems like a lot of trouble, but only takes 1-2 minutes with practice and only needs to be done once unless tips or regulator settings are changed. Also, note that at no point are you depending on or even looking at regulator gauges, which can be very unreliable when abused. This method will work with all standard OA equipment for welding.

Last edited by Northweldor; 10-08-2005 at 05:51 AM.