Why Acetylene?

Jewelry Discussion
81 
 Just a qick note on gas leaks:  While it is useful to use
soapy water to *find* a leak, just watch your gauges as you
turn off your tanks to see if you have one.  If the gauges
hold their pressure after the tank is turned off, you are leak
free!

Red light just went on when I read this. My acetylene gauge has
never gone back to zero ever since I bought my rig. (It’s a
Smith torch and bought the whole thing through Rio.) I have
changed tanks and it still reads the same. Figured it was just a
temperamental guage.

Should I worry? Please tell me when to panic! :slight_smile:

Candy Glaze

82

in all this propane acetylene discussion nobody has
mentioned methane We hear stories about how “toxic” methane
is . . . are those stories inncorrect?

G’day; methane is no more toxic than any of the other gases used
in jewellery making. Coal gas contained all sorts of things,
including hydrogen, carbon monoxide, methane - and a swag of
other things and it got it’s bad name mainly through the carbon
monoxide content. Methane, propane, butane, hydrogen, acetylene

  • none of these is particularly poisonous. It is when there is
    too little oxygen to sustain life that ‘toxicity’ occurs with
    those gases. Unless, of course there is a nice mixture in the
    atmosphere just waiting for a light. It is a good thing to be a
    bit paranoid, but don’t overdo it. Cheers, – =

          /\
     / /    John Burgess, 
    / /
   / //\    @John_Burgess2
  / / \ \
 / (___) \
(_________)
83 
My acetylene gauge has never gone back to zero ever since
I bought my rig.  (It's a Smith torch and bought the whole
thing through Rio.)  I have changed tanks and it still reads
the same. Figured it was just a temperamental guage. Should I
worry?  Please tell me when to panic!  :)

Candy - sounds to me like your needle is stuck. When you turn
OFF your tank, the needle SHOULD hold - this means the pressure
of the tank is being maintained in the lines without tank
support, meaning no leak. An hour or two later seepage will
probably have brought your needle back towards the zero area.
You might try tapping on the glass to knock your needle loose.
Generally you can also remove the glass (or plastic) and maybe
fix it that way. Good luck, Mike

← end of posting →

84

Hmmmm . . . sounds like you have a defective gauge! Mine starts
off above F (full) and usually ends up below “E” (empty) I
didn’t buy mine at Rio, but all the torches I’ve seen work the
same way . . .

85

Neal–I am absolutely obssessive about turning off both Little
Torch tanks when I will not be using them for several hours. I
double check the valves as well. It’s worth the extra effort of
turning them on again when I need them to ennnsure that they are
safe. Sandra/ElegantBee

86

Candy said,

Red light just went on when I read this. My acetylene gauge has
never gone back to zero ever since I bought my rig.

That’s goodness (as far as leaks are concerned).

Here’s the proceedure used in industry & recommended by the
American Welding Society for shutting down an oxy/acetylene (&
other gases as well ) torch when finished using it:

1.Turn off the gas at the torch.

2.Turn off the oxygen at the torch.

3.Turn off the gas at the tank (Note: Acetylene tank valves
should NOT be opened more than 1 1/2 turns).

4.Turn off the oxygen at the tank (Note: Oxygen tank valves
should be opened FULLY when opened. There is a seal in the full
open position to prevent leaks of the oxy due to the 2000PSI
pressure in the oxy tank.) This applys to refillable oxy
cylinders.

5.Open the gas valve on the torch to bleed the gas still in the
lines.Watch the needle on the high pressure guage (usually the
right hand guage) of the gas regulator, it should go to ‘0’.

6.Loosen (counter clockwise) the pressure adjusting screw on the
gas regulator until it turns freely. This prevents possible
damage to the regulator gauges if the start up proceedure is not
followed the next time the unit is used.

7.Close the gas valve on the torch.

8.Open the oxy valve on the torch to bleed the oxy still in the
lines.Watch the needle on the high pressure guage (usually the
right hand guage) of the oxy regulator, it should go to ‘0’.

9.Loosen (counter clockwise) the pressure adjusting screw on the
oxy regulator until it turns freely. This prevents possible
damage to the regulator gauges if the start up proceedure is not
followed the next time the unit is used.

10.Close the oxy valve on the torch.

Dave

87

Do you drain your gas line after you shut down the gas tank?

Marilyn Smith

88

Hi Everybody,

My two cents worth on the torch gas issue. In my shop in Canada
I use both propane and oxygen (Meco torch, weldmaster casting
torch) and acetylene & oxygen (Little torch). Each torch has
it’s strong points.

Pentimento the shop I’m involved with in the Detroit area uses
the same with the addition of a natural gas & oxygen for the
Meco’s and a Hoke torch for melting platinum using propane &
oxygen. We use a manifold set up for many stations.

No.1 I would suggest that new jewellers take a welding one
class because there is to much to be covered well
even on this forum. The more you know the safer you are!

No.2 Maintain your equipment! Candy Glaze don’t panic but do go
and get your regulator look at by a good welding shop. A repair
is usually fraction of the cost of a new regulator.

If grandpa is giving you his weld set up replace the hoses and
look at them really well at least once a year.

It’s nice to check with soapy water when install the system but
you should also recheck your connections and make it monthly
(Benches get moved, hoses are moved constantly) habit to keep
ahead of leaks.

When buying regulators, try to buy the type with both line
pressure and tank pressure (capacity). This is extremely
important for acetylene because of it nature. Acetylene should
never exceed a line pressure of 15 psi, that why the red line on
the regulator. Anything above that and it becomes explosive at
the regulator. 5 psi is normal and safe.

How then you may ask can safely store large amount of the gas?
The tanks are filled with pith like substance which is saturated
with acetone which the acetylene is dissolve into safely. Which
bring up another problem with the gas. Never use the tanks
sitting on there side. The acetone leak into the regulator and
eats up the gaskets and hoses. If you must transport the tanks
on there side, let them stand upright for half a day before
opening the valve.

The big reason why propane needs to be handled with care! Yes
it’s heavy and pools on the ground and will explode if lit. But
this not the big reason.

“It’s because of the safety valve on barbecue tanks.” If you
have a tank filled in the winter when really cold. And the kid
slightly overfills the tank or just fully fills the tank. And
you then bring the tank into your nice warm building the content
expand. This exceeds the limit of the valve which then releases
the extra pressure. Which is when you hear the hissing noise and
turn off the tank and take outside to release about five pounds?
This is exciting!? Yes,No. We still bring the tanks inside the
shop though, but we do get the propane guys to slightly under
fill the tank in winter 17 1/2 lds. for a 20 lds. tank which they
happily charge us full rate for. As far as I’ve seen normal heat
around tanks has no effect like direct sunlight or really hot
summer days. No direct heat though.

Make sure to chain up all tank so they can’t be knocked over and
knocking off valves from oxygen tanks. I’ve heard they make
great rockets.

Again take a welding one course, this is only a fraction of
that you will use every day as jeweller.

P.S. Nice to see you Dick Caverly on Orchid.
Jim From Pentimento Fine Jewelers and Alpine Custom Jewellers
alpine@hay.net

← end of posting →

89

So Let me see if I got this straight, according to your list,
acetylene is the 3rd safest gas to use?? Certainly its safer than
propane…

<-- end of posting -->

90

I think it may be necessary in this whole discussion to mention
that there are two main types of regulators for acetylene
torches. This may help quell some leaking paranioa.

One kind has two dials…one that reads the pressure of the gas
when regulator is open (when you close regulator this goes back
to zero) and one that tells you how much gas is left in the tank
(this one gradually decreases over time, reading zero when the
tank is empty…and should not change when the regulator is turned
off).

The other, less expensive and more common kind has only one
dial. It reads the amount of gas left in the tank ( again, it
gradually decreases as you use up gas, but should not change
when the regulator is shut off)

Hope I helped calm some fears…
Susan

<-- end of posting -->

91 
So Let me see if I got this straight, according to your list,
acetylene is the 3rd safest gas to use?? Certainly its safer than
propane...

Hi Dede,

I’m not sure who’s list your referring to Dave’s or mine. If you
learn the safety rules for any of the gases there equally as
safe in my experience.

The only difference is that one is better for a certain job than
another. My sentimental favorite is natural gas for all round
work, but it doesn’t have enough pressure for platinum, ergo
propaine.

Jim alpine@hay.net

92

Hello Jim!

Well I was told that acetylene burns hotter- making it better
for jewerly especially for big pieces. Also I was told acetylene
is nearly as dangerous as propane…Also I have been told
acetylene doesn’t pool around the floor like propane…Is what I
believe true?

DeDe

93 
 ...procedure used in industry and recommended by American
Welding Society for shutting down an oxy/acetylene (& other
gasses...)torch.... (Note: Acetylene tank valves should NOT be
opened more than l 1/2 turns...)

Thanks Dave for the orderly procedure to follow in shutting down
a torch. Much has been said on the use of acetylene, which I have
used, but my setup at home is oxy/propane. Can you tell me how
far propane valve should be opened for use? Appreciate the info.,
Laurie

94

Hi Laurie,

Can you tell me how far propane valve should be opened for use?<<

I’ve never seen anything in print, but you can apply the same
(acetylene valve opening) logic to any gas. Just open the tank
valve enough to maintain the regulator low pressure setting
when the torch is lighted. ie: If the regulator low pressure
guage is set for 3 pounds, the tank valve should be open far
enough to provide the volumn of gas necessary to keep the
regulator at 3 lbs while the torch is on.

FWIW: I never have to open my acetylene tank valve more than
1/4 turn. I=

use a 2 stage regulators.

Dave =

95

Re: opening propane valve

Thanks Dave for the info. I had heard differently from one source and wanted
to know the real deal. Still learning…

Laurie

96

I have used oxy/acetylene for fabricating platinum. The only way it works is by using an oxidizing flame. Anything less will contaminate the platinum.

97

22 YEARS LATER.

Way to reopen a thread.

1 Like
98

Sorry about that! There are several groups that I belong to on FB. Aspiring Metalsmiths etc. all basically for people that want to learn the trade. Many use butane creme brûlée torch’s or

Propane plumbers torches. Every time someone wants to get a real torch the debates start! I didn’t even see the date. Sorry about that! I was just trying to find some additional info and I shared my experience with oxygen/acetylene and platinum.

1 Like