Oxy acetylene consumtion

[Boedie]

Hi all, been thinking about this topic - probably a little too much. I have Harris 25 regulators, victor 100fc torch, #2 tip, full size tanks(forget size), run 10/5 for oxy/acet, and fillet braze moztly. Should my tanks empty about the same time? I feel like my acetylene emptys alot quicker than my O2. For instance, currently my acetylene has 50psi and O2 has 1000psi. Any thoughts? Time to rebuild regs?
Thanks,
Chris

[Andrew R Stewart]

First thing I thought of is the safety rule to not run A over 7PSI, I was taught this 45 years ago and also run my A and O about the same at 4/5PSI each. I also see my A emptying out quicker then the O for "the same size" tanks.

The flame is what determines the relative rate of gas consumption. A neutral flame will use the same amount of gas independent of the reg's output PSI. I use a neutral or a slightly reducing flame for the vast majority of my work. Andy

[edoz]

Three things, your oxygen bottle is probably larger and is filled to a much higher pressure, acetylene is suspended in a porous material in the bottle to stabilize it, which takes up space inside the bottle. So not only do you have more oxygen in a larger bottle, but there is nothing else in the oxygen bottle taking up space. For normal brazing you'll run out of acetylene faster than oxygen. Torch bottles are paired based on consumption for cutting, as it's more common than brazing in modern industry. For bike builders who don't do anything but braze with their torches, it's not a bad idea to go up a size or two on your acetylene bottle.

[Boedie]

Thanks Eric, Andy. That's the answer I was looking for Eric. In my mind, I couldn't figure out why they would pair these 2 bottle sizes, but that makes sense about cutting with the higher O2 pressures.
Thanks,
Chris