Help me understand neutral flame vs BTU's

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Aren't all neutrals flame created equal--The same temperature.Larger welding tip more BTU's not necessarily more temperature.Help me understand.Still thinking about the High pressure o/a welding issue.
Reply:Well there are some formulas I've seen but never dabbled with that get into actual realized BTU whereby you need to calculate cubic fuel flow per time frame such as hour/minute. So in a highly simplified example a small orifice with high pressure could be the same btu as a large orifice with low pressure. That would be in a highly controlled situation in a perfect world.
Reply:Neutral flame is one in which the main byproduct is carbon dioxide which shields the HAZ. This is created by a balance of the correct amounts of Oxygen to Acetylene. As long as you have balance, you have a neutral flame. BTU's are the amount of actual heat being produced. A number 000 tip can be balanced neutrally the same as a number 4 tip. But the bigger tip creates more actual BTU's...British Thermal Units, therefore...more actual heat.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:o/a welding has been frustrating forme because it seems getting  the right flame is so elusive. if its not too strong, blowing the puddle around, its nice and soft and too cold. My oxygen  regulator outlet gauge has a scale of 0-150 psi which is as useless as breasts on a amphibian. With a probable highest - you'll ever need- pressure of 50 psi, why not change it out for a gauge with a scale that lets you approximate 3-4 psi for welding with some chance of success? but all the good welders say its not done with gauges anyway....
Reply:The first kind of welding I learned to do was O/A. I was taught by an older guy who had been welding since the 30's. He never worried about pressures, and I never did either. He taught me what the flame should look like, and he taught me to do my adjustments at the torch.As far as I know, (and I am no expert on O/A, but I have done it quite a bit over the years,) to get a neutral flame, you start with a carbonizing (rich) flame and then lean it out until the little tails go away, at that point it is neutral.Joewww.CummingsHauling.com
Reply:Originally Posted by weldbead... My oxygen  regulator outlet gauge has a scale of 0-150 psi which is as useless as breasts on a amphibian. With a probable highest - you'll ever need- pressure of 50 psi, why not change it out for a gauge...
Reply:great idea denrep.i can get a 0-10 psi gage on a hose fofr checking pressures when welding, the 0-150 is ok for setting it to 35/40 for cutting.
Reply:Originally Posted by denrepMy favorite regulators are the gaugeless ones, with just a pop-up to indicate tank pressure.When you really must know precise pressure, you can take a gauge reading at the tip. Just push a short hose with gauge attached, over the tip.Good Luck
Reply:Thanks guysMy thinking is that a tip has only one optimal pressure/flow.  That optimal setting works on a range of metal.  It is not designed to provide a range of BTU's out, but one optimal Btu output.  Most book I have read state to adjust the acetylene until the soot clears or the flame jumps away from the tip the reduce it.  Then find a neutral flame.  I have never seen anywhere that is says use one tip over a wide range.Though, I am included in the using one tip and adjusting the setting.This could be a source of some frustration for some new o/a welders.  A different tip is needed with different setting, rather than same tip different settings.Those this sound correct.
Reply:Thanks, Joe. That is about the simplest explanation of setting an A/O welding tip I've seen. Same thing goes on a cutting torch except you need to fine tune the setting with the cutting air flowing. When the heating cones don't change you have that one too.No one tells you this but each tip has a fairly large heat range. If it won't get hot enough then it's time to get a larger tip. Maybe the manufactuers don't explain this so they can sell more tips. LOL. Experience and experimentation are great teachers.
Reply:Originally Posted by weldbeadgreat idea denrep.i can get a 0-10 psi gage on a hose fofr checking pressures when welding, the 0-150 is ok for setting it to 35/40 for cutting.
Reply:To address your original question which we seem to have lost track of: Yes, all neutral A/O flames are created equal producing about 6000 degrees F. The larger the tip, the more BTU's or heat produced. Creating a neutral flame is easy---after you learn how. Kinda like running 7018 overhead. Ain't nothin' to it--- once you learn how.
Reply:Originally Posted by joethemechanic welders in Kansas
Reply:Originally Posted by tapwelderThanks guysMy thinking is that a tip has only one optimal pressure/flow.  That optimal setting works on a range of metal.  It is not designed to provide a range of BTU's out, but one optimal Btu output.
Reply:Originally Posted by TEKbut........we're not in Kansas anymore, Toto
Reply:I wonder what the rate is for steam shovel operators in Saskatchewan?Joewww.CummingsHauling.com
Reply:Excellent post, Craig, but I think you are just wasting your time.
Reply:Absolutely not a waste of time.  Thanks for the post....Just trying to get new knowledge to set with prior knowledge and experience.  I haven't attempted to lay down any laws here.  Just a coincidence these gas welding threads came up when I happen have done quite a bit of brazing and some welding over the last two months.  Oldtimer, I actually tried you method and confirmed that it did work.  I also reported problem that I had.  That statement was not deserved.   Later