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Propane tank pressure

Hi all

I would like to use compressed air/propane and was wondering how
much pressure is developed in a propane tank like the ones used
on a BBQ. Would it go up to , say 7 or 8 psi.

…Leo Doucet…Fredericton, NB…Canada…


A 25lbs bottle will go up to 7 or 8lbs as you guessed. The
problems you must figure out first is how much gas are you going
to use, and how large a torch you are going to be using. If you
use the gas to fast, like a large torch, the tank will freeze up.
If you use a medium torch for melting metal you might get a
little frosting on the bottem of the bottle. If you are going to
use a Smith torch or the like a 25lbs bottle will last you a few
weeks and serve you well.

It is at about 150 psi depending on the ambiant temperature.
You can easily get 7-8 psi (I constantly use 20 psi for my kilns)
via a vairable gas resulator. Here in the states one of these
can easily be picked up at the gas supplier or most welding
supply shops. They cost about $35-40. Easily hook to the tank
and are easliy tapper into for use via gas hose.


John and Cynthia/MidLife Crisis Enterprises
Maiden Metals/C. T. Designs/Dach Ranch/etc.

PO Bx 44, Philo
CA 95466
Ph 707-895-2635 FAX 707-895-9332

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Dear Leo, I can assure that a barbecue Propane tank has
sufficient pressure (at room temperature) to operate an
Oxy-Propane torch. I set my regulator at 6 psi and my oxygen at
20 lbs… I use both a Hoke torch and a Smith’s “Little Torch” on
all types of fabrication, but primarily I fabricate Platinum
using the previously described set-up.

I do not have any experience with compressed air as an Oxidizer
instead of oxygen. But I’d bet money you can use a 20 lbs…
barbecue with no problems. (Aside from all the previous threads
concerning general torch safety and the specifics of
heavier-than-air Propane safety, its petty stable stuff.)

Leo: I use propane/oxy for casting and have a barbecue style
propane tank. You don’t even need a pressure gauge for that tank,
a waste of money. Its plenty sufficient for any torch. You can
actually use the regulators used for barbecues etc. but I went to
a gas store and got an adjustable regulator for the propane tank,
it has no gauges but allows you to adjust the pressure which is
handy ifyou’re running a Little Torch or something. Hope this

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Exactly my experience. I cannibalized my barbecue tank this
year (having run out of acetylene over a weekend) and hooked up
the Smith Little Torch. Wonderful! Totally economical, and
resupply is just down at the gas station for a ten buck refill
when I need it. So I hooked up a Y-adaptor, bought another Smith
and run both torches now (propane is fabulous, but has too wide a
flame for certain fine work).

Oh, I have to disagree. I use my meco with propane/oxygen for
many years, and will work with any size flame and project. For
casting, and melting, I have a long tube (copper, by the way!)
casting torch, that has served very well for all golds and
silver. I simply regulate the pressure on the propane with my
gaugeless regulator. Curtis

 So I hooked up a Y-adaptor, bought another Smith and run both
torches now (propane is fabulous, but has too wide a flame for
certain fine work). 

G’day; In my experience the width or fineness of a torch flame
has very little to do with the fuel gas used. I have worked (at
different times) with acetylene; air or oxygen. Hydrogen; air
or oxy. (used for quartz ‘glass’-blowing) Coal gas; air or oxy.
Propane air or oxy. No natural gas experience. In every case,
the size of the flame has had to do with the nozzle of the torch
(but it does have a little to do with the gas pressures) and not
the fuels and oxidant. For the last 20 years I have used a
’self-blowing’ Swedish-made propane-air Primus torch with four
different nozzles, giving flames from a pencil point (which I
use for soldering 2mm jump rings for sterling chain,) to a 25 mm
nozzle which I use for melting small amounts of scrap and
occasionally, the bronze welding of small steel parts, and for
hardening and tempering steel tools. I also use a tiny torch
I’ve had so long I don’t remember where I got it which I used 48
years ago for certain glassblowing jobs, and which was intended
for oxy-coal gas, but I use it with oxy-propane and for things
like ring sizing. Incidentally, there are now no coal-gas
generating plants in New Zealand. I also have a bronze-welding
torch for oxy-propane which I use a lot for all sorts of things.
So I repeat, the size of a flame has to do with the torch and
it’s nozzle and not so much the fuel. Cheers,

    / /
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  / /__|\      @John_Burgess2

At sunny Nelson NZ