Pre-Heat Oxygen Pressure for Oxy/Acet Cutting

[djhammerd]

Could someone explain Pre-Heat Oxygen pressure to me, and how it is accomplished if I set my regulators to cutting pressures?

[LDW]

Here is a chart I found. I usually set the Oxygen on 40 psi and the Acetylene on about 10 psi. I am not sure what your question is. Open the bottom valve(for the oxygen) when cutting all the way. This lets the oxygen flow full force while cutting.

[irnsrgn]

preheat pressure/volume is set with the valve under or to the side of the cutting oxy handle, cutting oxygen is full force straight thru the torch. the main oxy valve at the hose on the handle should be wide open.

[arftist]

LDW, So do you use 40 psi of oxygen for all your cutting needs? Just curious.

[LDW]

Yes, I have always set the oxygen regulator at about 40 psi

[djhammerd]

Thanks for the advice and information thus far provided.

I have done further research online and found that setting pre-heat oxygen pressure is not associated with the equipment I have. My equipment has only two hoses (one for oxygen, one for acetelyene), with a single regulator for each hose. Evidently, some setups have a second oxygen regulator and a second oxygen hose.

I found a Victor "Welding, Cutting and Heating Guide" that states "Pre-heat Oxygen PSIG" is applicable for 3-hose machine cutting torches only. With a 2-hose cutting torch, preheat pressure is set by the cutting oxygen"

I was confused by tip and pressure charts that have columns for pre-heat pressures, but did not qualify their use and requirements.

Update.... A little more qualification...

When it states that the pre-heat pressure is set by the cutting oxygen, it means that the user sets a single oxygen pressure, that being the oxygen-cutting pressure.

The follow-on process to create a proper pre-heat "cone" evidently limits the oxygen flow for the pre-heat oxy/acet mix.... and thus provides for a proper oxygen volume (SCFH), as opposed to contolling the amount of oxygen used by the pre-heat by pressure.

Anyway..... If I understand it correctly, that's how it must work.

[irnsrgn]

3 hose torches are straight torches used for machine cutting, like my pattern torch shown below.

[arftist]

LDW, Not to be a wise guy at all, But I adjust my regulators almost any time I use my torch. The thicker the metal, the more pressure and vice versa. Even If your average pressure only went to 30 psi, you would save 25% on your oxy bill alone. If you don't cut much it probably will not matter much.

[LDW]

I do not think you are being a wise guy at all, That makes good sense. I do not do a lot of cutting, but I still hate to have to get the bottles filled. Everything I learned about a torch was doing plant maintenance years ago with oxygen I did not have to purchase. I was just being honest. Thanks Artfist, thats another reason I enjoy this site.