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Is propane safer than acetylene?


Hi there,

I currently have a standard oxy/acetylene torch setup that I use in
my home studio, and I have some anxiety about storing acetylene in
my home. Is propane safer than acetylene? Can I get a propane
regulator for my torch and keep using it as is (its a standard victor
torch)? My fiance and I just bought a house and I don’t want to blow
it up!


I just went through re-setting up my studio and changing over to
Propane Oxygen. I’m not sure how many admonishments, warnings and
case studies I received via ganoskin. All of them valid of course.
Some folks who had witnessed the destruction were understandably
quite passionate about the tales.

Funny part is that a few weeks later, I took a class with a local
long-time local jeweler-- who had never even heard of a flash-back
arrestor- and had kept propane gas, acetelyne etc. in his studio for
centuries-- and the insurance agent and fire marshalls never said a

Well, my husband and I decided, thanks to Orchid, better safe than
sorry. We constructed a doggie door to my studio. The doggie door has
a locking outer door. When opened I feed the hoses through right to
my bench, then remove them when not in use.

I suppose the torches (which are housed in an open, but sheltered
tin housing attached to the outside of the studio) might be
vandalized. But in this Austin neighborhood, they are more likely to
be struck by lightining. Yikes, hadn’t thought of that one 'til now.

Apparently, the propane tanks have a release valve which functions
in temp fluxuations-- and the heavy gas stays at floor level and will
blow you sky high if somehow sparked-- (i.e. outlet sparks, etc.)

The acetelyne will also blow you sky hgih-- though it mainly
accumulates at a higher level in a closed building.

Consider a locking doggiie door-- mid wall level.

Austin, TX


Hi All:

Overall, acetylene is safer, as it is lighter than ambient air and
does not out gas and pool to the floor, as does propane. However,
with propane, it depends on the size of the tank you use. If you use
the very tiny propane tanks, about 1 foot in length, these are quite
safe and don’t vent. The larger B size will, as will the BBQ style.
Acetylene in the B size (about 2.5 feet) is fine.

When to change your tank? Acetelyne is mixed with acetone. At 25psi,
I usually make the change at that point.

When switching out tanks, always, always, always, (did I say
always?), make a leak test. When I get my tanks refilled, I check
them right then and there with my hoses and regulators at the welding
supply where I get my gas. I have found, one more than one occasion,
where leaks were present on the square fitting where the tank key
turns on the gas. Welding suppliers, clink and clank tanks all day.
They don’t care the way we care, (well maybe they do). However, when
I am driving home with gas in the back seat in its little seat belt
with the window cracked open, I want to know that the tank is working
properly before I become a scene in an action blow up thriller.

Yes, it is fine to drive with your tanks in your car. You drive with
a gas tank in your car. However, up end your tank and let it settle
for at least an hour. This gives the acetone a chance to rest back
into the bottom.

I use a double regulator, meaning one that measures the gas pressure
in the tank and one to measure the gas pressure in the line to my
torch. Now that little T bar on the regulator? When you turn off your
gas and bleed the line, unscrew the T bar on the regulator, meaning
turn it counter clockwise, like you are turning down the volume on
your tuner. I find more people, cranking the regulator tight thinking
this is the “off” position. No, this is the “on” position.

A regulator contains an interior rubber diaphram which detects how
much pressure is being REGULATED through your settings. If you leave
your regulator in the “on” or cranked in position, eventually you
will wear out the diaphram and you will lose the sensitivity on your

For those using oxy/fuel for the first time and trying to figure out
the order to turn on the fuel and the propellant (oxy), just remember

This stands for:

Gas on (light it up)
Oxy on (regulate flame)

To turn off:

Oxy off (to cut off the propellant)
Gas off (to cut off the fuel)

Strikers for Gas/Oxy. I don’t use them. I find that the gas pools
too much in the striker compartment and WOOSH when the spark hits. I
really like the little automatic battery operated clicky things that
give off a continuous spark. There is a nice round one with four
access points. Nice design. A little gas and it ignites away. Great
for people who are lefties, as the strikers are designed for

For Smith Air/acet users. About once a month, check the integrity of
the two “O” rings and make sure there are no cracks. This torch tip
depends on a very tight fit between the torch tip and handle. The
handle will get hot, if the o rings are not working properly.

Bleeding lines. After the gas is turned off, I light my torch and
when the flame is gone, so is the gas. Turn your torch off and back
off the regulator.

Lastly, something that people don’t address enough. Flashback
arrestors. Get’em, use em. Especially if you are going to solder at
home, or anywhere.

Hoses, check for leaks here too. I had leaking aceteylene in my
basement, and couldn’t for the life of me figure out where it was
coming from. I did leak tests, regulator checks, fitting checks,
nothing was making sense. Then I did a close inspection of my rubber
hose. Ah. Seems that my cat Heloise found that the rubber was a
perfect toy to munch on, and I found tiny cat tooth punctures in my

If your hose on your straight Prestolite or Smith air/acet has been
around for more than five years, replace your hoses. The rubber can
break down and become brittle. If you don’t believe me, ask the
famous sculptor Albert Paley who nearly burned to death using
propane/oxy on one of his large sculptures, and an old hose cracked
and ignited the gas for 20 feet, right up to his face. He’s ok, but
old hoses should be checked.

I know this is a long discourse on a simple question, but I suspect
there are newbies lurking and this is for you folks.

Happy Soldering!

Karen Christians
Waltham, MA


Hi Richard;

Propane is more dangerous indoors, because it is heavier than air
and tends to pool in low areas. When it does that and gets ignited,
it’s very explosive. Acetyline is kind of dirty when there is no
oxygen burning in the mix. It rains down small floaters of black
soot. But it will disperse better than propane. Still, it’s a
flamable gas and has to be respected. It’s hotter than propane, so it
can be a little difficult to control for a small torch.

You could do what I’ve done, which is to get a large propane bottle,
barbeque size, and keep it outdoors. Then, get a few small bottles
like you use for a propane camp lantern, and re-fill them from the
larger bottle. You can get this fitting to fill small bottles from
Harbor Freight for around $10 (maybe more now). Problem is, you have
to have a regulator designed for these bottles, which is easy to get
and not very expensive. Rio, Stuller, etc., sell them. It’s just
that those aren’t 2 stage and have no guages, so you don’t get to see
how much pressure you have, you have to guess, and you can’t tell
when the bottle is nearly empty, so keep extras handy. Still, the
small bottles are legal to have indoors, and there’s not enough gas
in them to blow an house to bits. A full bar-bie bottle can take out
a 2 story home, no problem. Hollywood does all their explosions with
propane because it’a a very showy explosion, lots of rolling

David L. Huffman

I currently have a standard oxy/acetylene torch setup that I use
in my home studio, and I have some anxiety about storing acetylene
in my home. Is propane safer than acetylene? 

Truth is, they’re both pretty dangerous:) One benefit to acetylene is
that it has a very distinctive odor (garlic, with a sharp element
from the acetone). That being said, I maintain a healthy fear of it.
It has the widest explosive range of any gas in air. Propane needs
to be between 2.1% and 9.5% percent to be explosive, whereas for
acetylene the range is 2.5% to 90%. I would be far more comfortable
with propane in a house than acetylene personally.

Paul Anderson


Talk to your local fire marshall to see what they allow and what
they feel a safe set up would be. Also, tank size makes a difference
with propane. Smaller tanks (under 5lbs.) are not as dangerous
indoors as larger tanks (or so I have been informed).

Melissa Stenstrom



Is propane safer than acetylene? Can I get a propane regulator for
my torch and keep using it as is (its a standard victor torch)? 

There are several points to consider when comparing the 2 gases from
a safety standpoint.

Acetylene is more prone to explosion from shock than propane. That’s
one of the reasons hat acetylene tanks are usually anchored to a wall
or some other point that’s not likely to tip over. The liquid
acetylene is absorbed in another material in the tank to reduce the
tendency to explode if shocked.

On the plus side, if there is a leak anywhere in your welding setup,
the acetylene will dissipate rather quickly & generally not present
an explosive condition.

Propane, while not as explosive as acetylene in it’s liquid state is
heavier than air & doesn’t dissipate as rapidly. As a result, if
there’s an undetected leak in your system, the propane can collect in
the lowest spot it as access to. If enough collects, any spark or
open flame can set off an explosion. In a house the open flame can be
from the water heater, furnace or some other source. A spark can be
generated by many electrical devices…

Regulators for propane are generally available at welding supply
shops. In some cases it may be possible for them to rework your
acetylene regulator to propane.



Richard-- the safest gas to use for jewelry is natural gas. Why–
because it’s lighter than air and will disperse more easily. Propane
and (I believe acetylene) are heavier than air, so they can pool and
collect from the floor up.

I also believe that acetylene is great for welding but not so great
for jewelry making-- too hot and especially too dirty. Acetylene
doesn’t burn as clean as natural gas or propane.

Propane is much cleaner burning than acetylene and the heat range
more suited for jewelry but has the safety issue I mentioned. If you
do use in house, just be sure to check your valves and connections
with bubble water everytime you change the bottle. I have a propane
torch with oxygen in my home, and just try to keep up the

If your new house has natural gas, maybe how much you can get a
plumber to route the gas to your studio. It will be cheaper in the
long run if you do a lot of torch work.

Also remember that oxygen is an accelerant for fuels, so be sure to
keep it away from oils, wax, etc. When I hired on as a jeweler for
my previous employer, I was horrified to find that he was using
bottled oxygen to pressurize his wax injector-- can you say “watch
out for the crater!” We fixed that right away, switched to bottled

You can get the correct jets for your victor for either natural or
propane no problem.


I also believe that acetylene is great for welding but not so
great for jewelry making-- too hot and especially too dirty.
Acetylene doesn't burn as clean as natural gas or propane. 

I have heard this before about acetylene.

I have used acetylene for 17 years for anything you can think of,
repair, casting, fabricating, alloying gold and sterling. For 12
years I cast between 18 and 36 flasks with between 250 and 350 grams
of sterling. I do not have problems using acetylene. I produce high
quality products and if using acetylene compromised the materials or
the quality of my workmanship, I would not use it. Denver fire dept.
allows me to have acetylene tanks in my building, but not propane
tanks. Connotation is that acetylene is safe, propane is not.

Richard Hart

Propane needs to be between 2.1% and 9.5% percent to be explosive,
whereas for acetylene the range is 2.5% to 90%. I would be far more
comfortable with propane in a house than acetylene personally. 

I wouldn’t, but then I could be wrong too. But here’s how I see it.
Although you are correct that acetylene has a far wider range of
concentrations within which it can be explosive, you’ll note that
this range starts at a slightly higher level than for propane, so
the tiniest of leaks probably can’t do it unless it’s a totally
sealed area, and fairly small, and remains undetected. Acetylene has
a much higher rate of dissipation in air, so leaked acetylene tends
to quickly spread out within a given air space, and it takes a good
deal of initial leak before you reach an explosive mix at all. Once
there, you’d have to pass all the way through that 8 percent range
both gases share, with no source of igntion present, before you’re
getting to the area where propane would be safer if there were that
much of it leaked. My totally unverified intuition would be that the
most dangerous situations would be where there is already a pretty
steady source of ignition, and all that’s needed is for the gas to
reach the lower level before things go boom. If it hasn’t ignited
yet at 10 percent, why would it somehow be more likely to ignite at
50 percent, for example. I’m thinking of things like electronics,
which might be on creating sparks, or most commonly, pilot lights on
water heaters or other gas appliances, etc. in basement workshops. So
with all that said, I can’t say I’m all that concerned with the fact
that acetylene remains explosive through a higher concentration range
than propane.

What DOES concern me is the other big factor, and for me, this is
the elephant in the room. Propane is heavier than air. Quite a bit
so. And it dissipates in free air only rather slowly. What that means
is that with a leak, the gas sinks to the floor, and pools there. A
much smaller amount of gas can build up to an explosive mix because
unlike acetylene, it doesn’t need to fill the whole space. it can do
this just in the first inch or two off the floor, near to the leak
or across the whole floor. And in addition to thus needing less gas
to be dangerous, it also means the telltale odor may not be as
strong. With acetylene, because it dissipates so rapidly, that odor
will be apparent farther away, and while the leaked gas is still at a
low concentration. With propane, you could have a leak of quite an
amount in the basement, and upstairs in the livingroom, be unaware of
it. And in that basement situation, the ignition sources of most
common concern, the water heater pilot light or similar circuitry,
tends to be near floor level, right where that gas can pool. And
next, look at the tanks. Acetylene tanks share the same valve
engineering and testing requirements as very high pressure tanks.
They’re built pretty strongly. While this doesn’t preclude leaks in
regulators or torch systems, at least leaky tanks themselves are not
so common, and perhaps not so likely to be undetected. Propane
tanks, while also usually well made, are generally lower priced, and
mass marketed. That might suggest a greater chance of manufacturing
defects. Plus, they’re engineered with an overpressure release
mechanism in the valve that can actually intentionally let gas out if
the tank gets warm. That doesn’t make me happy… And finally,
remember that while all torch hoses are compatible with acetylene,
the standard acetylene hoses are not comptatible with propane, which
can degrade them over time leading to leaky torch hoses.

Put all that together, and frankly, I’m of the opinion that propane
is the more dangerous of the two in an indoor home workshop.

With that said, I’m also of the opinion that with care, attention to
details and procedure, the relative dangers of either of these gases
is very low. To avoid problems, you have to pay attention to your
procedures, the maintenance of your equipment and the tanks, and to
making sure you’re working safely. But for the record, I have BOTH
acetylene and propane in my shop. If, some day, my posts to Orchid
abruptly cease, and you read in the news about some jeweler who’s
house blew up in West Seattle, then perhaps you can conclude that
I’ve been wrong in my choices and opinions. I do know I’m taking
risks, but I believe they are manageable ones, and acceptable for my



I received this today. It is an article that might save those of you
who use propane Please read the below Safety from the
Florida Department of Law Enforcement.

Lee Epperson

  Meth cooks are getting the propane tanks from Wal-Mart,
  Kroger, gas stations, etc. and emptying them of the propane.
  They are filling them with anhydrous ammonia (which is used in
  their meth recipe). After they are finished with them, they
  return them to the store. They are then refilled with propane
  and sent back for us to buy. Anhydrous ammonia is very
  corrosive and weakens the structure of the tank/valve. It can
  be extremely dangerous when mixed with propane and hooked up to
  our grills, etc. 

  You should inspect the propane tank for any blue or greenish
  residue around the valve areas. If it is present, refuse to
  purchase that one." If you suspect you already have one of
  these tanks, don't touch it. Notify the fire dept, DEA, or
  HazMat Emergency Response Unit immediately for disposition.
  Check out the following website for more details. They also
  have pictures showing what contaminated tank valve might look

Acetylene is more prone to explosion from shock than propane. 

Shocking it from what? There is very little loose gas in acetylene,
which is why it is stored with a matrix…acetone. The only issue and
reason for anchoring any gas cylinder down is to make sure that the
nozzle doesn’t break off under pressure.

Acetylene is dirtier gas, true, but overall, I can make amazing
things in silver or gold with my little air and acetylene torch.
Clean your metal, flux properly and don’t overheat. Check your paste
flux if you are using this style. It should be the consistency of
yogurt and clean! I watched many students use watery, dirty flux
wondering why their pieces would not solder.

Karen Christians
Waltham, MA


As someone just beginning to explore the world of soldering, is an
electric solderer a better choice? My husband has a pretty “healthy
fear” of propane and acetylene in our home.


Hi All,

Someone mentioned it is perfectly OK to drive with tanks in your
vehicle. I’d check on this. Even though many of us get the BBQ tank
filled and drive it home, many states have regulations about
placement of tank within a vehicle at a minimum, and some states
prohibit driving with pressurized gases on certain roadways and some
states prohibit it completely once the tank is a certain size, at
least in privately owned vehicles. Check and know your local rules.

Chris Ploof
Chris Ploof Studio
508.886.6200 EST

Meth cooks are getting the propane tanks from Wal-Mart, Kroger,
gas stations, etc. and emptying them of the propane. They are
filling them with anhydrous ammonia (which is used in their meth
recipe). After they are finished with them, they return them to
the store. They are then refilled with propane and sent back for
us to buy.

Holy moley!

I will pass this on.

I have always insisted on getting my own tanks refilled instead of
exchanged. This started when I had a nice brand new tank on my gas
grill and I wasn’t about to trade it in for an old beat-up one-- I
paid good money for new! I have continued this with my oxy,
acetylene, and my little propane tank I use with my Meco, even the
two huge propane tanks on my fifth wheel (my home-away-from-home in
some woods I own in Wisconsin where I thought I would build a cabin
but never had the money). Now I feel even better about it!

I have the good fortune to live close to places to get these filled,
but I think most aras have welding shops that can do this. And here
at least, U-Haul refills propane tanks!



For the reasons stated I think acetylene is the safer gas. Propane
pools, acetylene does not. It is also a fine gas for making jewelry.
I used an air/acetylene torch for years, before switching to
propane/ O2. I fabricate mixed metal jewelry. My a/a torch was a work
horse for me. I passed that torch on to a novice is a small condo as
I know its the safer gas.

When I fill my 5 gal propane tank, I have them stop short of filling
it the full 5 lbs. I do regular leak tests. Its been a fine set up
for years now too.


Truth is, they're both pretty dangerous:) One benefit to acetylene
is that it has a very distinctive odor 

Everything that everyone has written on this thread that I’ve seen is
true. I will maintain again that gas is gas. It’s not unhealthy to
think that one is MORE dangerous, but it is hazardous to think one is
LESS dangerous. Any serious accident with any gas is going to be bad,
and it’s not to say there aren’t choices to be made. One of those
little disposable propane tanks can take out the side of your house
if it’s given a chance. On some level there is no such thing as a
"safe" gas, and “safer” can be deceiving, too.



There is widespread fear of fire, especially among those with little
experience with it. People seem to really panic about the notion of
compressed fuel gasses exploding. I was looking around my studio the
other day, thinking about all the potentially dangerous tools and
equipment in my shop. Over the years, I have hit my fingers with
hammers, sliced my fingers with knife blades and gravers, sawn and
drilled into my fingertips on occasion, among other things, and I
think that is par for the course. Metalsmithing is full of dangerous
tools that can hurt you in a myriad of ways. But in all the years I
have been metalsmithing, I have never blown myself up with a torch,
or know anyone else who has. Certainly, it has it’s dangers, and
gasses need to be handled correctly, but I just don’t see where the
fear comes from.

My advice would be to make friends with the torch, and discover all
it can do for you. Practice using it, and get comfortable with it.
Electric soldering just won’t cut it, I’m afraid. The torch,
whichever type you choose, will help open up the world of
metalsmithing to you.

Jay Whaley


As a previous Explosive Ordnance Disposal Technician, I never
worried whether I was working on a fused 500 Lb or a 750 Lb bomb!!!
They both will hurt when handled incorrectly. Gas is Gas and "ALL"
precautions have to be taken. Home, House, Shop, Garage, Condo,
Apartment, they all deserve respect and the utmost precautions. Be
like me and never let someone read about a bad incident.



The topic of which gas is more dangerous comes up regularly on
Orchid. This is a reprint of one of my posts from 2002

Both propane and acetylene have their own individual pluses and
minuses when it comes to safety.

Many people seem to focus on the fact that propane is heavier than
air and tends to pool. This is absolutely true, but… when a
combustible gas leaks in an enclosed space such as a home studio with
limited ventilation, it doesn’t make much difference whether the gas
is heavier or lighter than air. If it has no place to go it will
accumulate until it can somehow dissipate via an open window or
through ventilation. If it sees a spark before it dissipates then it
has a real good chance of exploding.

My approach to safety with these gasses is to minimize the amount
that I keep in my home studio. I use propane and MAPP gas and limit
the amount in my home to one disposable tank of each. Smaller
inventory of gas means a smaller explosion, if the gas does indeed

If acetylene was available in small disposable containers ( and I
believe that it is not) I would probably still not use it. This is
because acetylene has a much greater explosive range than propane.
This means that gas from a tank of acetylene leaking in an enclosed
space (your studio) has a greater chance of exploding than the gas
from tank of propane leaking at the same rate…

While I am not specifically in the propane or acetylene business, I
have been working as a chemical engineer in related industries for
almost 30 yrs and spent part of my career doing hazard analysis on
industrial oil and gas facilities

Milt Fischbein
Calgary Canada