[TheForge] Thanks for the info: learning to use a cutting torch properly

[Jerry Frost]

The subject's been covered quite well so I only have a little to add.

First, I get complimented on my torch technique fairly often, then they'll
tell me I should readjust my gages to 20/5 or some such. I use the ratio I
learned in jr. high school shop class which is basically what you'll find in
the manufacturer's manuals. The proper ratio is 2:1 twice the oxy psi as
acet. 10/5, 14/7, 20/10, don't go to 30/15, that can get BAD.

This produces a nice clean cut when your technique is perfected and no
matter how good you are if you vary far from it you won't get a good cut.
For practice, use as few aids as possible you don't want to become dependant
on them, my exception is a straight guide on long cuts and circle cutter, I
try to do everything else free hand to keep myself as sharp as I can. (not
very <grin>)

There's another important reason not to deviate much from the 2:1 ratio.
Safety. The rate of propogation for an oxy/acet explosion is right around
24,500 fps. That's pretty close to orbital velocity, slightly less than C4.

If you're running a 4:1 ratio, 20 oxy : 5 acet something really ugly can
happen. If some crud blows back (much more likely with this out of balance
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. Imagine standing next
to a 25' coil of det cord and setting it off.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.



> Great batch of info- thank you all who replied!
> I've been buying steel at a shop that does a lot of cutting jobs on thick
> (1" to 5") stock- torch cuts that look almost like laser...made me ashamed
> of mine. Have seen some awful plasma cuts here and there too, so I suppose
> that's not a magic bullet either...
> Couple of further questions:
>
> 1) I usually hold the torch so that the cones are just barely off the
stock-
> is that the right distance?
> 2) When you say correct gas pressure, do you mean fuel or oxy, or both? Is
> one more critical?
> 3) Always thought that 35 ox was about right for general work- is that
what
> makes my cuts slaggy on the far side?
>
> Andy Gladish
>