[TheForge] : learning to use a cutting torch properly

Sat May 31 14:08:00 2003

There have been a lot of good tips on torch work offered.
I might as well put my 2 cents in again.
To set your torch for welding and cutting, after insuring your tips are
clean and in good shape.
Turn your second stage valve off on the acetylene and O2  regulators. Open
your acetylene  and O2 valves on the torch to full open.
Slowly open the second stage valve till the acet. gauge reads the
recommended pressure for the tip size.
Light the acetylene plume in a safe direction.
slowly open the second stage valve on the O2 regulator until the flame at
the tip just reaches off feather (neutral flame).
Finally fully depress your O2 cutting lever and re adjust your O2 second
stage for just off feather.

With excess gas pressure you over heat the cutting area.
With too high a O2 pressure you supply more O2 than needed for the narrow
clean kerf desired.
When you over heat the cut area you produce more insulating slag that
decreases the cutting action and melts the metal around the kerf.
Excess O2 can even cool the preheat area.
When I first tried to cut my 5 1/4" anvil stock it was a total disaster till
I went back to my welding books and realized that I was using way too much
O2 pressure for the cut.
Chuck
----- Original Message -----
From: "Peter Fels And Phoebe Palmer" <[email protected]>
To: <[email protected]>
Sent: Saturday, May 31, 2003 2:40 AM
Subject: Re: [TheForge] Thanks for the info: learning to use a cutting torch
properly

> Frosty may well be correct on his 2-1 ratio for cutting, he is most
> generally  right on, on his advice.
> So I feel uncomfortable in contradicting him...but
> I've often used  much higher ratios without a problem for  the last 30
> some years without a problem. I am careful about the condition of my
> tips and flashback valves, rate of acet withdrawl, overheating , not
> cutting with a near empty acet tank and all that sort of stuff. Have
> been cutting a lot of 1/2" plate the last few years running 35 oxy and
> 7psi  acet on a pipeliner sized smith torch and a #2? 6 hole cutting tip
> without problem. And I've gone considerably higher  on occaision. Above
> 15 psi acet approaches  instability of course. Good flashback valves are
> imperitive...especially on the acet side.
> That doesn't mean it's good practice ( I'm self taught) but it does
> lower the odds of probable catastrophy.
> Frosty's "up the acet hose and blow you into a nice fine mist." sure
> gets a guys attention though!
> Andy, let me say again, oxy pressure is keyed to tip size and metal
> thickness.Mostly, oxy overpressure is just expensive.
>
> Gladish Family wrote:
>
> >Thanks, Frosty, Pete, et al...
> >I'll try running much less 02 and see if that reduces the slag.
> >
> >
> >
> >>ratio) and plugs the tip just right, the much higher oxy pressure can
back
> >>up the acet hose and blow you into a nice fine mist.
> >>
> >>
> >
> >I have a son who plays a lot of Dungeons and Dragons who says that
turning
> >into a fine mist is an important skill. I think he means Make Believe...
> >Andy G.
> >
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