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

Fri May 30 20:56:01 2003

Oh!!! Frosty Hit on my favorite subject.  24,500 FPS is a very cool number.
The key word is stoi�chi�om�e�try.

Thats a perfect mix between Oxy/Aceytlyene.  I like the reference to det
cord.  Imagine a 150' long piece of 5 mil anitstatic plastic bag roll (we
make smaller bags from the large roll of tube with a heat sealer)  Then
imagine some idiot and all his buddies, and 3 full 235 CF sets of oxy/acet
tanks, and a mixing valve preset to the perfect mix...........

We are talking 24" diameter det cord here..........................  Same
concept Plastic 55 gallon drums work well to, but don't forget the grounding
rod, and piece of copper wire.

Actually this leads to something productive.  For a show for anyone who
feels loud noises are fun.  A very safe way to play with oxy/aceyt, is an
old compressed gass cylinder.  20# aluminum. or 155 CF steel cylinder work
the best.  Cut the cylinder off so it has an open top to about 24 - 26"
tall.

grind the top sot it isn't sharp.

Next find some saftey gear, EAR PLUGS, not EAR COVERS, A face shield and a
pair of sturdy gloves.

Place a piece of newsprint over the top, and use a large rubber band to
secure it.  before lighting the torch use the tip to punch two holes in the
top the same size as the tip up to the nut 180 degree's from each other near
the edge..

Snuff a neutral flame,  place the tip in one hole, and allow the cylinder to
fill for 45 seconds,  move the torch away from the tank, re-strike it and
wave it over the tank, lets just say the whole neighbor hoos will be awake.
It perfectly legal, and terribley loud as well as very safe.  Unless you
care to stick your hand over the tank.....  Then prepare to loose some skin
and arm hair.  We actually have these noise makers approved, in the state of
Oregon, for race starting and other events, and have been using them for
years.  Anyone in the Salem Oregon area, has probably heard us, even people
as far a Silverton.

Pyro Boy

---aka-- Original Message -----
From: "Jerry Frost" <[email protected]>
To: <[email protected]>
Sent: Friday, May 30, 2003 11:19 AM
Subject: Re: [TheForge] Thanks for the info: learning to use a cutting torch
properly

> 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
> >
>
>
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