acetelyne torch

Anonymous-0 · Aug 14, 2012

What pressure settings should I have on my guages for the acetelyne and oxygen when using a cutting torch

Russ from MN · Aug 14, 2012

Depends on tip size, I think 4&20 will work.

flying belgian · Aug 14, 2012

Really depends on the situation but try 15 and 50 for starters. Then as you are cutting you will see why you want to change either one.

Walt Davies · Aug 14, 2012

10 to 15 lbs on the acc.
30 to 40 on the oxy.
Adjust up or down according to tip size.
Walt

504 · Aug 14, 2012

For OX what ever works for you, for Acetylene 15psi is the max, 16 and you could have big problems. I run 8 to 10 and have cut 3/4 inch steel.

MarkB_MI · Aug 15, 2012

Most torch manufacturers post tip charts on their web sites. Settings vary widely between different tip sizes and different torch models.

gene bender · Aug 15, 2012

The settings are determined by the tip you are using and the tip is determined on how thick is the material. Most people use more pressure than they need.Get a chart it will tell you how to set for the tips same with using the welding tips.

JOHNNYfromMI · Aug 15, 2012

15 is the MAX on the acetelyne!
Any higher than 15# pressure the gas becomes unstable and can ruin your day!

RodinNS · Aug 15, 2012

As always it depends on the tip size... but 5 on the acetylene and 15 for O2 is a general rule of thumb. If you're cutting something and it doesn't burn off clean then you need more O2 pressure...
I use propane rather than acetylene myself... and with LP I will run 10-12 # on the gas pressure... but always remember that acetylene is unstable in free air at pressure greater than 15 psi. It can explode. BEst to keep it's pressure down closer 5 psi.

Rod

Anonymous-0 · Aug 15, 2012

Can't believe some of the responses! 4 PSI of acetylene will cut over 8" thick. For general cutting on say 3/8" steel, 4 PSI acetylene and around 30 PSI on oxygen is a good starting point. You can adjust the oxygen pressure to suit the thickness you're cutting. Acetylene pressure won't make any difference at all. If you're using a heating tip, then you need to increase the acetylene pressure. Having a clean tip and a nice long straight cutting jet will do more to produce a good cut than having an exact pressure setting.

JML755 · Aug 15, 2012

(quoted from post at 23:22:47 08/14/12) What pressure settings should I have on my guages for the acetelyne and oxygen when using a cutting torch

I use no higher than 5 on mine, just what I read in the manual and by looking at the charts. The 15 is not a working pressure as stickweld says.

CBBC · Aug 15, 2012

Thanks Rod, I was going to ask about propane. I'm paying for tank rental and hardly use the torchs. I think I will try Propane and only pay the rent on my O2.
I have a few BBQ style tanks and I know my regulator will fit the valve, but will the propane work on my forklift bottles? I know I will need an adaptor...
What pressure do you run the O2 at with the propane?
Thanks, Grant

RodinNS · Aug 15, 2012

I don't know about the forklift tanks.... I would assume that they have the same valve on them since I don't recall anyone around here having a different fill whip for forklift bottles.... but honestly I've never looked.
You may need to install a couple long nipples on the regulator to clear the neck ring on the BBQ tanks tho.

You also need LP tips for your torch...

I run roughly the same O2 pressures. Mabey a bit higher. Basically just what you need to make it work right.

Rod

Russ from MN · Aug 15, 2012

The forklift bottles that we used were liquid withdrawal, but there was another port for vapor, which is what you want for a torch. This port was plugged, so there would have to be a fitting installed. I think most forklifts use a special fitting, ours did.

Walt Davies · Aug 15, 2012

How does that work when it's 350 in the tank. A lot of old wive's tales out there.
Walt

bill mart · Aug 15, 2012

How it was explained to me:
"Gaseous" acetylene is unstable over 15 psi, which is why it's dissolved in liquid acetone in order to store it at ~275psi. Bill

Anonymous-0 · Aug 15, 2012

Wive's tale? There is a porous material inside an acetylene cylinder that is then filled with acetone. The acetone absorbs the acetylene gas so it is stable above 15 PSI. When filling an acetylene cylinder the amount of acetone is measured and then the appropriate weight of acetylene is added. The fill pressure is 50 PSI and it still takes a long time to fill. The maximum size of pipe for filling is 1/2" and it's double extra heavy pipe. When filling the cylinder is cooled with water. Why do think acetylene cylinders are so heavy? Have you ever noticed a black type liquid when using a rosebud? It's from withdrawing acetylene too fast and is the acetone. I toured a cylinder fill plant.

JML755 · Aug 15, 2012

(quoted from post at 18:38:44 08/15/12) Wive's tale? There is a porous material inside an acetylene cylinder that is then filled with acetone. The acetone absorbs the acetylene gas so it is stable above 15 PSI. When filling an acetylene cylinder the amount of acetone is measured and then the appropriate weight of acetylene is added. The fill pressure is 50 PSI and it still takes a long time to fill. The maximum size of pipe for filling is 1/2" and it's double extra heavy pipe. When filling the cylinder is cooled with water. Why do think acetylene cylinders are so heavy? Have you ever noticed a black type liquid when using a rosebud? It's from withdrawing acetylene too fast and is the acetone. I toured a cylinder fill plant.

Stick,
good info. thanks.

Paul from MI · Aug 15, 2012

If you go with propane, as I have, be sure your get compatible hoses. Regular acetylene hoses will fail after a time. Propane works fine for cutting and brazing, not too sure, never welded with it.

CBBC · Aug 15, 2012

Thanks guys, I think I will get a LP tip and see how it goes. As I said I have a lot of propane bottles as well as propane for forklifts.
I'll ask my propane guy about the tanks.
Grant

JOB · Aug 15, 2012

I was told 5 Acetylene and 20 oxygen. From many years of experience 7 acetylene and 40 oxygen works the best for me. If your torch has two oxygen valves on the handle you should open the one closest to the regulator wide open, and use the valve closest to the tip to adjust your flame.

You should not empty an acetylene cylinder in less than 7 hours. If you do acetone will be in your acetylene. Acetylene tanks are filled in 7 hours also, unless the process has changed.

A tip will only handle so much pressure. To see how much pressure your tip will handle set your acetylene at 3 pounds, set your oxygen at 3 pounds. Light your torch, open your acetylene valve all the way. You should have a very sooty flame, increase acetylene pressure slowly, your flame should be connected to the tip. When the flame leaves the tip you have too much pressure, decrease pressure a tad. Adjust acetylene valve so flame is connected to end of tip. Now open your oxygen valve on the torch all the way, increase pressure until you get a neutral flame. That is all the oxygen pressure you need to run that tip. The above information is for gas welding and brazing, and welding tips in general.

If you starve a tip for acetylene it will pop out. If you have too much pressure on your lines your are using the valves on your torch handle for regulators.

VicS · Aug 15, 2012

Looks like you got a lot of good answers. All the (Junkers) use Lp. A grill bottle of LP will outlast at least 4 big bottles of oxygen. Our local scrap yard uses a 1000 gal tank of LP and a Semi-trailer of liquid oxygen. Cutting up coal mine equipment up to 12 inches thick. It takes a little longer to to heat your metal hot enough to cut with LP. But seems to cut cleaner, for me at least.

Anonymous-0 · Aug 15, 2012

You're partly right but for equalizing a welding tip you don't even need a gauge on the regulator. Some acetylene cylinders will be empty in 10 minutes. The withdrawal rate for acetylene is 1/7 of the cylinder capacity per hour not 7 hours. This can be exceeded for short periods if you're using a heating tip for example. Similarly larger acetylene cylinders take longer to fill but they usually fill more than one at a time

20 PSI oxygen is probably good for about 1/8" material. 40 PSI will cut over an inch thick but it depends on which size of tip you are using.

Anonymous-0 · Aug 15, 2012

Only an oxy/acetylene flame is a true neutral flame and that's why it is the only fuel that can be used for welding.

JOB · Aug 16, 2012

stick weld your first two sentences don't even make sense. I am not a mathematician, but doesn't 7 hours equate to your withdrawal rate. The withdrawal rate for acetylene is 1/7 of the cylinder capacity per hour not 7 hours. I have emptied large acetylene cylinders in 3 or 4 hours using a #15 tip and never seen a black type liquid as you mentioned in another post. I have seen the flame look a little different, maybe a little feathery. I assumed that was the acetone burning. 7 lbs of acetylene and 40 lbs of oxygen works for me. I can cut clean and quick. And I use a #1 tip. You set your pressure at anything you want, whatever you like. What ever works best for you.

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