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Melting silver with oxy/acetylene


#1

I have been using a Little Torch with a standard tip to melt silver
for casting (usually about 50g) and contacted a Toronto store
(Lacy’s) about getting a Rosebud tip. The salesperson said that no
jeweler in the Toronto area uses oxy/acetylene to melt silver unless
it is a huge amount, like a kilo. He said that oxy/propane is the
standard. Can someone explain to me why this is so?

Stan Burris


#2

I, too, use the little torch for melting small amounts of silver and
gold. Many of us do. It works fine - better I find that oxy propane.

Tony Konrath
www.goldandstone.com


#3

Stan, I would consider Oxy/Acetylene as too hot a fuel mixture for
working with silver. Acetylene alone is a hot burning fuel and when
you ad O2 it just gets too hot. Acetylene/Air (atmospheric air added
at the torch head at a preset rate) such as a Smith, Goss or
Prestolite, on the other hand, is quite a nice fuel mixture for
soldering and working with silver and even casting small to medium
amounts.

Silver (sterling, whatever) is notoriously fickle. I casting,
things can go from pleasant to ugly in 50F, a much smaller window
than gold. With the added heat punch of Oxy/Acetylene, the potential
for frying your castings is that much more. In addition, acetylene
is a dirty burning fuel and if you run out on a Saturday or Sunday
may be difficult to refill. Not so, of course, with propane.

All that being said, I’ve seen people produce beautiful work with
everything from a cigarette lighter to a laser: It’s really in the
hands of the artist and the technician. I prefer Oxy/Propane for the
qualities noted above and the wide variety of flame characteristics
offered by a fuel and oxygen mixture.

Hope that helps, Andy Cooperman


#4

May I suggest you use a safer gas like natural gas? Plenty hot and
no compressed gas cylinder full of a fuel gas. Acetylene has its
hazards being heavy and explosive and very carbon laden. Yuck! Until
you dial up that oxygen, what a mess! Propane is cleaner but it is
heavier than air and should not be stored indoors at all. Hydrogen is
very hot, very clean, and much, much lighter than air. Very explosive
over a wide range of concentrations too. If you get a leak, it goes
up and away from you fast. I wrote an article called “Torch Song” for
AJM a few years ago and reviewed all the gases for jewelers. Check
that out. It may help. Get the right rose bud torch for any gold or
silver torch casting

If you wish to consider electricity, Kerr makes a nice little
furnace that runs plenty well for sterling and yellow gold. The
"Handy Melt" I think its called.

Daniel Ballard


#5

Hi Stan,

The salesperson said that no jeweler in the Toronto  area uses
oxy/acetylene to melt silver unless it is a huge amount, like a
kilo. He said that oxy/propane is the standard. Can someone explain
to me why this is so? 

Everyone has their own reasons for doing things, however in this
case a couple of the reasons may be the same from person to person.

Generally, (in the US) propane is available at more locations than
acetylene. It’s also less expensive. And 3rdly, it’s cleaner burning
(although not quite as hot) than acetylene.

Dave


#6

Oh me oh my, ten years of casting 500 to 1000 pieces a week with
oxy acetylene, no fried casting, no explosions, no porosity. I have
never “burnt” metal. Either ignorance is a blessing or I am one lucky
bucko. I also have a barbeque type propane tank next to my bench
indoors in my retail shop, where I am inspected every year by the
fire dept., apparently they are ignorant too. They say nothing about
the tank. They are concerned that I have a exit sign over the door so
my customers will know how to get out of a room where the only exit
is where they came in, 600 sq. feet to get lost in, one whole wall
is glass facing outside. I told them the person who can’t find the
door in a fire is going to be to stupid to read. I have customers who
are concerned about someone switching their diamond while it is
being worked on. I ask them if they know anyone that had their
diamond switched, and in ten years only one person actually knew
someone that had that happen. Sounds like these fuel and tank
stories. Does anyone actually know of anyone that had a tank
explode, had physical or property damage due to acetylene or
propane tanks. I know it has happened and could happen, but are the
odds as great or greater than you having a car accident while taking
your tank to get refilled? Due care and diligence with safety
precautions has been reasonable for me. When I cast, I like my big
oxy-acetylene cutting torch blazing away, melts 250- 350 grams in
about 2 minutes. I have to go light my torch,

Richard Hart


#7
 Does anyone actually know of anyone that had a tank explode, had
physical or property 	damage due to acetylene or propane tanks.

Well, actually, yes. A few months ago on Jewelers Row in Chicago,
on the upper floors of 5 S. Wabash, there was a tank explosion that
shut down the building for weeks, damaged more than one store/shop
on those floors and put lots of jewelers out of work for weeks.

That much I know from the TV news.

Elaine Luther
Chicago area, Illinois, USA
Certified PMC Instructor
eluther@copper.net


#8
    stories. Does anyone actually know of anyone that had a tank
explode, had physical or property damage due to acetylene or
propane tanks. . . . Richard Hart 

Hi Richard; I’ll bite. Here’s a couple true stories.

case #1.

My father, a glassblower, was doing a little lampwork (benchtop
glass blowing using pyrex tubing and a large torch) in a room off the
back of his house. He has been doing this sort of work for over 30
years. The valve on the propane tank was defective (this happens
more often than you’d think). My father is in his 70’s, and his sense
of smell isn’t what it used to be. A small spark ignited the pool of
gas that had accumulated around the tank. He tried to smother the
flames with a coat lying nearby. When it appeared he had put out the
fire, he lifted the coat, and a huge fireball rolled up and across
the ceiling. He got some minor burns on his arms and face, but fled
the house as the entire roof burned off and the place was thoroughly
charred throughout.

case #2

Two years ago, about a quarter mile from my home, a family was
renting an old mobile home. They were rather poor, as were most of
my neighbors, and couldn’t afford to have the big propane tank
outside refilled. The father got the bright idea to try to hook up a
smaller 20 pound propane tank to keep the furnace running. There was
a leak, and the gas was ignited by the pilot from the furnace. The
family got out OK, except for the family cat, but the mobile home
burned completely to the ground.

My point is, you’re right, driving a car is statistically more
dangerous. But if we had as many people using propane tanks indoors
as we do people driving cars, I think you’d see the statistics
change. I wear a seat belt and shoulder harness when I drive and
keep checking my blind spot. When I use tanks and torches, I check
for leaks when I put on the regulators, chain the bottles to the
wall, shut off the regulators, back out the T-wrenches and drain the
lines when I’m done. I never run an acetyline tank completely out, I
store propane outdoors, and never in an enclosure. These are habits
I developed when the safety and property of others was at stake,
such as employers, co-workers, students. Now it’s mainly so my kids
will have a live, healthy father as long as I can be that for them.
Make safe working habits into a sort of “grounding ritual” and rather
than having people think you’re a sissy, they’ll think you are a
Zen-like master.

David L. Huffman


#9

Richard in Denver,

Does anyone actually know of anyone that had a tank explode, had
physical or property damage due to acetylene or propane tanks.=

YES! My father had a workshop in his attatched garage and used
proane for his heater and torches; one day after getting a fresh tank
of propane he proceded to get to work as normal (and I might add that
he had worked full time as an installer and trouble shooter for
National Fuel Gas…a utility in Buffalo, NY for 35 years). After the
workshop had warmed up, the propane in the tank became more
pressurized due to expansion and leaked from the tank’s safety
plug…pooling propane on the floor without his knowledge. He was
doing some grinding of tool steel when a spark ignited the gas puddle
and blew the garage walls two feet from the foundation and melted the
synthecic shirt/jacket he was wearing to his skin. A fire ensued
which, in his shock, he was able to put out before he realized that
he had third degree burns over 30% of his body. The burns required a
hospital stay of two weeks in intensive care and muliple skin grafts
and pig skin applications to heal the wounds.

It can and it does happen, even to some one who has used and worked
with gases for their livelyhood, Be forewarned that it is against
code here in Colorado to have more than a five pound tank of propane
indoors and you are courting disaster…no mater how experienced you
are.

Paul Reilly, in Colorado Springs


#10
    Does anyone actually know of anyone that had a tank explode,
had physical or property damage due to acetylene or propane tanks. 

I know a fireman who went to a garage fire once involving an
acetylene tank. It was determined that the tank had some kind of
fault on top that finally got jiggled enough to make it go. The tank
ignited and was blowing a several foot high flame out of it’s top
when the firefighters arrived. Thanks to the owner who had it well
chained as it should be, it ignited the garage but stayed put.

His fellow fire fighters spent the rest of the day telling him
stories about tanks that hadn’t been chained and had shot across the
street while burning…through a couple of walls etc. He now works in
an office, he realized he wasn’t suited for firefighting as he kept
having dreams about burning acetylene tanks flying through walls at
him.

Karen


#11
Sounds like these fuel and tank stories.    Does anyone actually
know of anyone that had a tank explode, had physical or property  
damage due to acetylene or propane tanks. I know it has happened
and could happen, but are the odds as great or greater than you
having a car accident while taking your tank to get refilled? Due
care and diligence with safety precautions has been reasonable for
me. When I cast, I like my big oxy-acetylene cutting torch blazing
away, melts 250- 350 grams in about 2 minutes. I have to go light
my torch, 

Yes. It was about 1 1/2 years ago locally. An undetected propane
leak in a residence was ignited by someone lighting a cigarette on
the other side of the room from the propane source. The flash
explosion injured the smoker, and a small child pretty badly. Due
diligence makes fuel gasses safe under most circumstances, but the
laws on handling them have to be based on the least common
denominator. The odds are long, but the consequences when something
goes wrong are so severe, that the authority having jurisdiction has
to make a call.

Ron Charlotte – Gainesville, FL
@Ron_Charlotte1 OR afn03234@afn.org


#12

Good Lord! I have been using oxy acetylene for 30 years, I prefer
it’s high temp and controlled flame, it allows me to fuse as no
other mix has. Hyrdrogen just doesn’t have that quick high heat. In
sizing silver rings with stone in place it is invaluable! As far as
caution of tanks exploding? well a plane wheel can fall outta the
sky too! As long as your exercise caution and secure your tank
[never drop the gas tank] you will be just fine…
Ringman


#13

Hello, I removed my 20 lb propane bottle as soon as I read Orchid. At
one time my home was heated with propane, I hated it. I worked in a
machine, welding shop at a large public utility, and we had oxy/ acet
lines at all welding stations. The main line pressures were
regulated,

with a relief valve set below 15 lbs. We were all trained by the
bureau of mines in the safe-use of fuels .Idid know better, but I did
not do at home the way i did at work . Many of us are guilty of this.
I have been following all the remarks about torchs, and I have picked
up some good ,but i would like to add to it.

Seven pounds acty pressure will do anything needed. Fifteen pounds ,
and an explosion is likelyto happen. Acety bottles should always be
upright… Both lines should be purged before lighting-the torch just
in case there is acety in the oxy line,or vice versa.-I have seen the
front of a reulator blown off . The hoses were out 100 feet In order
to reach the field job.That cover might as well been an artillery
round.when it blew. No one was hurt, and back flow valves were
ordered, and in stalled on Every rig. Do not try to get more heat by
adjusting the flame with alternating adjustments of oxy, and acety.
GET A LARGER TIP! This practice will put both gas and oxy in the same
line and, boom when the torch is lit. I have rambled enough.It
happens as we get old, and senior moments strike without warning-


#14

A couple of years ago in Philadelphia there was an incident in which
a car parked on the street exploded, demolishing the car and injuring
the owner. At first the police thought it was a car bomb, but they
later found out the man had just had his acetylene tank refilled, and
he had it on the back seat. It had a slight leak. He parked the car
and went to run another errand. Wen he returned to his car and opened
the door, a spark from the car’s dome light ignited the gas and blew
his car to kingdom come.

Janet Kofoed