I am in the process of setting up a bench at home and I am concerned
about the safe use of Acetylene. I have a Presto-lite torch and an
acetylene B tank. I intend to get a ventilation system called a
Power Cat to divert soldering fumes.
I recently read that acetylene should not be used with silver
(http://www.c-f-c.com/specgas_products/acetylene.htm). Is this
true? I have used it for silver in the past during formal
instruction at a local university.
Is a Flashback Arrestor necessary in this application (using
ambient oxygen)? If so, should it be installed at the regulator?
Is there a device available to specifically detect acetylene gas
leakage? If so, where do I get it?
Any available would be extremely appreciated. Thanks,
Martha
I believe that the caution refers to the material of the container in
which the acetylene is to be stored, not the metal on which the gas
is used for soldering or welding.
The restrictions you have seen do not apply to your type use. pure
copper , high copper brass, pure silver and mercury form
materials under pressure that are shock sensitive with acetylene.
Standard welding equipment will not contain these materials . The
most important thing for youm is to use standard materials and nit
pipe acetylene in copper tubing. It is common practice today to use
flashback arrestors with acetylene. These can be at the torch or
after the regulator. they have not always been required in the past.
The best leak detector for you is a brush and soapy water. a weak
solution of a liquid dishwashing soap [ (Joy) is nomally used in
acetylene production units. It works , is cheap and available.
Thecylinders you use should be rust and dent free – generally look
good. There are some fuseable devices on the cylinder bottom that
should be checked for leaks as well as the topside connections. Don’t
exposure cylinder to external fire. You should be able to get
safety from you supplier. Commercial acetylene may
have a very definite odor. Yours probably does. Jesse
Martha, I solder silver, gold, copper, you name it, all the time with
an oxy/acetylene Little Torch. Although I don’t have them, flashback
arrestors are a good safety idea. The idea is to prevent a fire from
reaching your regulator/tank and potentially causing BOOM! A remote
possibility if you have safe, careful work habits…but the potential
is always there and you can never guarantee that someone won’t come
along, turn some valves, etc. I think acetylene has a very strong,
distinctive smell…I don’t know if there are electronic leak
detectors for acetylene. I check my fittings with some soapy solution
anytime I hook up new bottles or change hoses.
Can’t be too careful with this stuff! Best, Mike Dibble
The problem acetylene gas in contact with copper is that it forms a
solid copper acetlyide. These are shock sensitive and explosive.
The same is true for silver. Fortunately the reaction is slow and
acetylene gas cylinders typically have acetone in them to retard
metal acetylide formation (in the cylinder). Fortunately for all of
us, the burning acetylene on a silver or copper surface is not a
problem.
1. I recently read that acetylene should not be used with
silver (http://www.c-f-c.com/specgas_products/acetylene.htm). Is
this true? I have used it for silver in the past during formal
instruction at a local university.
I’ve used acetylene successfully for years with silver. Check the
archives as there has been some lively debates on the plus and
minuses of each type of gas.
2. Is a Flashback Arrestor necessary in this application
(using ambient oxygen)? If so, should it be installed at the
regulator?
Yes and yes.
3. Is there a device available to specifically detect
acetylene gas leakage? If so, where do I get it?
I just exchanged my empty acetylene tank for a full one today. I
asked the welding shop about gas leak detectors and they said the
ones the can order are for commercial welding shops that need to
comply with OSHA. $6,000 was the price range they quoted me. I’m
sure there are less expensive options out there. I recently
installed a Kidde Carbon Monoxide and Explosive Gas detector in my
workroom. The instructions say it will detect propane and natural
gas. I have tested it with acetylene and it did trigger the alarm.
The alarm sells for about $70 at your local home center and runs on
household current with a battery backup.
Your mileage may vary and I’m not endorsing Kidde products or their
use. I’m just stating how I am using the product and sleeping a
little better at night…
Martha, I have been using acetylene with silver for over 30 years. I
have never had a problem and I will continue to use it. I also use
acetylene and Oxygen mixed for use with my minitorch. It is
important to have a regulator on your tank. You will one that tells
you the amount of pressure in your tank and how much gas you have
left.
It is absolutely necessary to test for leakage when you attach your
regulator. You do this by mixing some soap and water and making a
sudsy mixture. You take this mixture and rub it around the the
fixtures that are attached. If it bubbles (blows bubbles) then you
have a leak and you need to tighten your regulator.
The problem acetylene gas in contact with copper is that it forms
a solid copper acetlyide.
Brian’s right on target with the above statement.
In fact the building codes in most of the US require that ‘black
iron pipe’ be used for transporting fuel gases if they’re piped from
a central source to the point of use.
I know of instances where building inspectors have required building
owners to remove copper gas lines & replace them with black iron
pipe. The only exception to the black iron pipe is the short
(usually 3 feet or less) length of flexible steel tubing used
between the end of the pipe & the gas using appliance.
I think what ever caution you read does not refer to using Acetylene
for soldering silver. If the statement is true there are a big
bunch of silversmiths that have been taking a risks by using
Acetylene to solder their artwork. Good Luck