Acetylene, Propane, Mapp and Oxygen Gases – Torches, Hoses, Regulators, Setup

The following information is based on my own experiences and research and is for informational use only.  Your reliance on any of this information is at your own risk!

Author:  Nancy LT Hamilton

Last edited:  3/22/18

On the following pages, you’ll find a lot of information about Acetylene gas, tanks, hoses, and regulators.  But, there is also information about Mapp gas, oxygen, propane – and information on torches, hoses, regulators, and setup – related to these gases.

Nancy LT Hamilton 2/23/17

What is acetylene?

Acetylene is a gas that is colorless, odorless and lighter than air.  While it might try to be stealthy, with it’s colorless/odorless nature, no one will likely miss its explosive nature, for acetylene is a highly explosive gas.  Acetylene is sensitive to shocks and likes to explode violently. To control its explosive nature, it is stored in specially designed cylinders and mixed with other things like acetone.

Acetylene is used for soldering/welding/cutting and was used for running the lights on motorcycles and buses, as we shall see! Acetylene is a hot gas which can burn at temperatures of up to 6,300 °F/3,480 °C.  Watch those fingers! Ouch!

History of Acetylene and the Acetylene Tank

Talk about a hazardous job.  This probably beats crab fishing as one of the most dangerous occupations!

  •  In 1896 two French scientists, Georges Claude and Albert Hess,  discovered that acetone can “dissolve many times its own volume of acetylene” ( “History: Acetylene dissolved in acetone”).  The acetylene is mixed with Acetone and then poured into a porous mass. The theory being “an explosion cannot spread in a tube with a diameter of a fraction of a millimeter”.  Claude and Hess,  worked to find a way to make compressed acetylene gas less volatile.
  • The original porous material that they used, developed voids in its structure and the acetylene gas filled the voids and exploded. It must have been a frightening research subject!


In 1906,  (Nils) Gustaf Dalén found a solution.   “Numerous unsuccessful attempts were made to prepare such a porous mass which would be sufficiently resistant and elastic to withstand the shocks encountered in transportation, without cracking and crumbling and thus producing cavities filled with explosive acetylene gas.” (Nobel Lectures, Physics 1901-1921).

In his presentation speech on December 10, 1912, Professor H.G. Söderbaum, (President of the Royal Swedish Academy of Sciences, at the time) discussed Dalén’s discovery:  “By a complicated and carefully developed process, this substance is enclosed in steel containers which thus become practical accumulators for the acetylene gas. The porous mass in the container is half-filled with acetone, and acetylene is then introduced by compressing it to a pressure of ten atmospheres. Under this pressure and at a temperature of 15° C, the container contains one hundred times its own volume of acetylene. The container is then ready for supplying to a lighthouse or light-buoy the acetylene necessary for lighting.” (Nobel Lectures: Söderbaum, H.G.)

Nowadays, Gustaf’s porous material – a mixture of diatomaceous earth and asbestos (perhaps, also cement and charcoal. See Air products’ page, Safetygram-13, under “Filler Material”), called  Aga.  Aga is still in use today.

Calcium silicate is often used as a replacement for asbestos.  Other chemicals/chemical compounds used are silica lime, asbestos, charcoal, and other materials.  The idea is to have a lightweight, yet porous surface to contain the gas.  The proportions of the materials are controlled by the Department of Transportation (DOT), in the USA.  This is to ensure that the material doesn’t crack even with rough use.  If crack forms, the gas and/or acetone can accumulate in it and explode.

Acetylene is still being mixed with Acetone and sometimes mixed with (DMF) Dimethylformamide.

On a personal note:  Gustaf became the managing director of AGA in 1909 (Nobel “Gustaf Dalén”).  In 1912, Gustaf was blinded while testing acetylene tanks.  He continued to work (at Aga) and invent until his death in 1937.

Gustaf was contracted to provide the lighting for the Panama Canal.

One of Gustaf’s many inventions was a flashing apparatus for lighthouses (around 1907).  The apparatus used a liter of acetylene to produce 10,000 small flashes.  This drastically reduced the amount of acetylene that lighthouses needed to use because they didn’t have to continuously burn.  In 1907 Gustaf also created the Sun Valve.  A simple, ingenious, little switch that turned off the acetylene (in the lighthouse) during the day and back on, at night.  No one believed that a device that simple could work.  The patent office insisted on a demonstration before approving the patent application.  It’s a pretty cool little mechanism.  Check out Aga’s page on the Sun Valve.

What to know before you begin

Notice:  Before setting up any torch system for the first time, consult with a professional at a bottled gas supplier like:  Airgas (USA), Praxair (USA), Calor (UK), Flogas (UK), Stargas (Australia), etc.  If you are still unsure of what to do, ask an experienced torch user to help you set up.

leaking-acetylene-tank-Vancouver-car  Plumber’s car explosion.  A leaking acetylene tank, an enclosed space, an electronic car lock, and BOOM!  (Image from the Vancouver Sun Plumber’s car explodes in Vancouver’s West End by Tiffany Crawford. May 22, 2013.)


The point of my scare tactics is that you should never leave your acetylene tanks in your car!  Don’t store them in enclosed spaces like closets, cabinets, and lockers!  Also, check for leaks BEFORE bringing them into your car or your home/studio/office/shop, etc. It is recommended that you don’t store tanks in your home.  Check with your insurance company and any applicable organization (housing association, landlords or managing agencies, etc.) as to whether you are in fact allowed to have the tanks on the property and if any damage is covered in case of a fire or explosion.

In Case of Fire!

If you have an out of control gas leak or fire:  IF you can and it is safe!!!!, turn off the gas, and then leave the area.  Call 911 (in the USA). Alert them to the nature of the problem:  “I have an acetylene gas leak or I have an acetylene fire”.  They have specific gas handling practices.  Don’t put your rescuer’s lives in jeopardy.  If you are in another country and don’t know the emergency number, here is a list.  If there is a person who is trained in handling acetylene fires they can:  if possible AND safe, shut off the gas.

If you have a small fire at one of the fittings on the torch AND If it is safe to do so:  turn off the gas and immediately apply a wet rag to the fire.  Leave the building and call 911.  The heat from the fire could cause the plugs on the top and bottom to blow – expelling large amounts of gas and or flames. This occurs at only 212°F (100°C)!!! (Information from Air Products, Safetygram – 13)

Note:  the following (in brackets) should only be done by a professional trained in managing acetylene fires. 

{Acetylene fires can be put out with dry powder or carbon dioxide fire extinguishers. If other tanks are nearby, water them down to keep them cool.  See why this should be done in the quote from Air Products below.}

Here’s a quote from Air Products’ PDF (see Required Reading for link) that should blow (pun intended) your socks off:

“The fusible metal plugs at the top and bottom of the cylinder will melt at 212°F. If the fusible metal plugs relieve, flames can be projected approximately 15 feet from the top and bottom of the cylinder. “

*For information on safe handling and other very important procedures for Acetylene and other gases, including oxygen, please see Air Products Safetygrams.

How to transport your cylinder

I spoke with Airgas today about my inability to find any Department of Transportation (DOT) information on transporting a single “B” acetylene tank in a private motor vehicle.  Now, I know why.  Boy, did I waste many, many hours on this one.  According to Airgas, there are no laws (in California) against transporting cylinders, weighing less than 1000 lbs, in your car, van or pickup truck – (obviously, at that weight, it would be more than quite a few cylinders).  There are no federal laws against the transportation of a few cylinders containing explosive/liquid or other gases a jeweler would use. DOT’S laws kick in at 1000 lbs (Type 2, I believe) but, I’m not getting into commercial transportation – beyond my scope of experience and definitely well beyond my level of interest in this subject!

gas-cylinder-cap  If you use cylinders larger than “B” or “C”, you should ensure that the caps are in place.  The smaller B and C cylinders don’t come with caps (at least not at Airgas or Praxair – to my knowledge).

So, if there’s no law against transporting the cylinder in your car, why won’t they carry them to your car?  Well, as with most things in this litiginous country, it’s so that they don’t get sued for damaging, dirtying or otherwise messing up your car – not because it’s against the law!  They will carry the tanks to your pickup truck’s gate though.  But, you have to put them in the truck and secure them.  Alas, so many forums, so much mis-information.  Unless, of course, Airgas is wrong.

If you know of any Federal laws prohibiting this practice, please contact me!

There are probably state regulations, that you should be aware of.  So, check those out.  Apparently, in California, there are no regulations against traveling with your little tanks.

So, safety rules, that I recommend if you are transporting gas cylinders in your vehicle. These are my recommendations – not rules, laws or requirements – just common sense (I do have some, you know!):

  • Bring a little testing kit with you and test the cylinder at the store.
  • Keep the windows open (at least in the back seat).
  • Don’t smoke anything.
  • Don’t leave the tank in the car.
  • Don’t travel with the regulators attached.
  • Don’t get into a fiery car crash.
  • If possible, keep the tank in an upright position.
  • If you must lay it down, let it sit, in an upright position, for a period equivalent to the time it was on its side – at the least – but, it takes 7 hours for the acetylene and acetone to remix and refill the spaces in the aga.  I would say:  leave it overnight!
  • If in the interior of a car: ensure that the tank doesn’t flop around, slide or fall over.   Wedge “stuff” around it so that it is immovable. I like to use my yoga blocks and shopping bags.
  • In a truck or van, strap the cylinder, (in at least two points) to the walls of the vehicle.  If you cannot do that, lay it flat and ensure that it won’t slide around – at all!  Maybe pick up the tanks after a good Costco shop and wedge it in with the cases of beer and boxes of groceries? Don’t forget to let it stand for at least 7 hours, if it was on its side!
  • Have the dealer pickup leaking tanks.  Don’t transport those – PLEASE!

Obviously, the safest route, to you at least, is to have the supplier deliver the tanks to your home.  It’s easier too.  They pick up the empty cylinder and give you a not-so-shiny, not-brand new one – but, it’s full of gas!  Nice. Just don’t forget to check that the cylinder valve is not leaking before they drive off.  This has happened to me twice!

OSHA states that: “When cylinders are transported by powered vehicles, they shall be secured in a vertical position.” 1926.350(a)(5)

See EIGA’s page for European regulations.

Things To Be Concerned About

  • If, when you get your new tanks (before the regulators are installed), and the stem or valve is leaking, don’t bring it inside! You did check this before bringing it into the house right?  If not and it’s leaking, bring it back outside. Call the dealer for pickup.  Be sure to tell them that the tank is leaking.
  • This recently happened to me: The system was all set up and working fine.  One night, as I was closing shop, I shut off the tank and drained my hose.  I noticed that the inlet regulator was still indicating pressure.  What to do? I wanted to scream and run around in circles but, instead, I had my amazingly strong and handsome husband (just in case he ever reads what I write) remove the whole setup from the studio, plop it outside and then I called the dealer. “Please pick this stupid cylinder up and bring me a non-leaking one right now!”  (Well, that’s almost what I said.)  Here are my recommendations on what to do if you experience the same situation:
    • Take the tank and regulators outside.
    • Call the dealer for a pickup.  Don’t forget to tell them that the tank is leaking.
    • If you are a nervous Nellie like I am, leave the regulators on the cylinder, then wait until the delivery person shows up.
    • If leaving the equipment on, be sure that the outlet pressure gauge is open (counterclockwise). This action will keep the gas from flowing into the hoses and the torch.
    • Double check that the torch is completely shut off too!
    • Remember to snatch your regulator, torch, hoses and key/wrench back from the delivery person – before they run off with them! You will probably have to disassemble the unit yourself, leaving you exhausted and with little strength left for a delivery truck chase.  Perhaps the dog can help?  I thought dogs liked to chase trucks? They did in the olden, but golden days of my youth. (P.S. – don’t, you or your dog, do this.  Ya hear?)
  • If the gas cylinder/tank is on and there is any fluctuation in the inlet gauge or the outlet gauge AND you are not using the gas: shut off the tanks, move the cylinder – with attached regulators – outside and call the dealer. They will advise you as to whether it is safe to remove the gauges or not.  This is probably a problem with your gauges – but, you should check with a pro.  Don’t forget:  The pressure WILL fluctuate (on both gauges but, mostly on the outlet gauge (the one that controls gas to the hose and torch) when you are soldering.  This is because the gas level is being lowered because you are burning it up!
  • At Chimera Art’s Jewelry Studio, which I am co-manager of, we often have issues with gas leaking into the regulator even after the system is shut down.  I believe that the problem is that people don’t shut the valve tightly enough to fully close it. So, check that your tank is fully shut down.  If you can’t manage it by hand, use a tank wrench.

What To Do If You Drop Your Tank

  • If you drop your acetylene tank – especially on a hard surface – call your supplier first. The tank is most likely fine.  Let is sit upright for two hours or so though.   I just spoke with Airgas and they said that there shouldn’t be any problems as the tanks are made to handle abuse. He told me, that he dropped a tank off of the truck, onto the tarmac of the parking lot and it was fine (hope I didn’t get that one!).
  • If you drop your acetylene tank with the regulators attached, go through the checklist below, before lighting the torch, and also follow the recommendations, above.
  • If you drop your oxygen, propane or other tanks, with (or without) the regulators attached, I’d go through the following checklist and ensure that none of the conditions listed exist.  If any of these conditions are present, purchase new or get the components repaired, call your gas dealer and don’t use your torch until it is repaired. The tank itself should be fine.
  • The Checklist: Check your hoses for evidence of cracks, burns, crushing, etc. Look for signs of damage with your regulators:  broken glass, bent connections, big dings. Check your tanks to ensure that there are no: holes, crushed areas, folds, bent stems, dings, etc.  If any of these conditions exist, don’t turn on the gas. Take the offending object to a gas professional like Airgas or Praxair. Whine a lot and blame it on someone else. Or, better yet, have them pick it up!
  • Chain your tank(s) to the wall or put it (them) into a cart NOW!  Dropping your tanks twice doesn’t make you look too good and is certainly not a recommended practice.
  •  If everything looks fine AND you had a little chat with your gas dealer, I’d check all connections for leaks, one more time.  It’s fun.  It is.  Really.
  • Open inlet gauge only, check for leaks, then open the outlet gauge, check for leaks.  If all looks good, light the torch.  Watch the gauges.  Test the system.  Turn it all off and watch to ensure that the gauges and the tank are working as they should. Now, go have a lie down.
  • Remember:  I am not responsible for any injuries or damages that may occur.  In all cases, I recommend that you check with a gas professional!!! I mean it!

Please read on for a zillion more words on this topic!

Fun Facts

Well, maybe not fun…but, important!

  • A full tank of acetylene has a pressure of 250 psig (pounds per square inch gauge).  PSIG is a comparison with the pressure around the gauge (the pressure on the earth). Most people (myself included) abbreviate it to psi.  Now, to get really confusing, there is another measurement of pressure:  psia.  Psia measures pressure relative to a vacuum.  A vacuum has 0 pressure (think: deep space). The atmospheric pressure on our planet is generally 14.7;  it varies a little, depending on where you are.    So, if for some insane reason, you wanted to measure the absolute pressure in your acetylene tank (psia), the formula would be:  (psig of the tank + 14.7 psia = psia of the tank).  Here it is in numbers:  250 psig plus the 14.7 atmospheric pressure = 264.7 psia.  Got it?  Suffice it to say that your regulator measures in PSIG, often abbreviated as PSI.
  • Never set your regulators higher than 15 psi(g) for Acetylene, when soldering or doing anything else!  What else are you doing with that tank?  Filling balloons is not a great idea, you know? Besides, not only would they blow up, they also wouldn’t float.  Sorry I gave you this idea.  balloon  Just remember the Hindenburg.  (To be honest, that was Hydrogen Gas.  But, the point is the same: don’t play with highly flammable, explosive gases – ever).
  • Acetylene is lighter than air – but, not as light as helium so, stop thinking about balloons!  You’d blow yourself up, you know!
  • garlic  Acetylene gas has been treated with a chemical to make it smell like garlic.  In it’s “wild” state it is odorless.
  • Acetylene cylinders are marked with DOT-8 or DOT-8AL.  This means that the tank has been made according to the Department of Transportation’s (Dot) specifications for acetylene (in the USA). See Virginia Tech’s website, under Cylinder Labeling to see more information on this.
  • The gas cylinders are not designed for temperatures above 125°F (52°C).  So, leaving them in a closed car, in the Mojave desert, mid-summer is not the best choice.  Actually, I was in Death Valley one summer when it was so hot that IF I had had a tank in the car it probably would have exploded. It was 126 degrees F at Furnace Creek, Death Valley.  We (sis and I) stupidly got out of our vehicle to see what being that hot was like. We decided it wasn’t really that much fun and got back in the, tankless, car.  The hottest it has ever been (so far) in Death Valley was 134 °F (57 °C) on July 10, 1913, at Furnace Creek. Glad we missed that day because, you know, we would have gotten out of that car! (Remember:  the top and bottom plugs will blow at only 212°F – 100° C!)
  • I only open my tank about a quarter of a turn (2″ – 3″).  This also makes it faster and easier to shut the tank off.
  • Shut the tank off at the stem using one of your tank key.
  • Please see:  What to Do First section of this site for further information in case of leak or fire. In case of a fire AND if it is safe to do so,  shut off the gas.  Call the fire department after you leave the building. Don’t forget to let the other residents of your home/studio/shop in on the situation!  Please, do your homework, on what to do in case of fire, have a plan in place and don’t have a fire in the first place!  Check out some of the many sources I’ve listed here for more information. Please read this page:  Emergency Response to Acetylene Cylinders by

The Nevers

  • Never set the psi on your acetylene regulator higher than 15 psi.
  • Never let your tank run empty, especially when using it with oxygen.  Oxygen can back pressure into the tank and cause an explosion. Also, debris from the bottom of the tank can clog hoses, cylinders and torch tips. Another reason: depending on the age of the tank, the acetone, that the acetylene is mixed with, becomes syrupy over time and can clog things up.  If your gas smells funny or burns weirdly, stop using it!  Who knows what you are burning (and inhaling).  Stop at when your pressure reaches 60 psi.
  • Never use your tank while it is on its side. If your tank has been on its side, let it stand, upright for anywhere from 1/2 hour to 24 hours.
  • Never let your tank freeze, Acetone and acetylene can separate – clogging hoses and potentially blowing you up.
  • Never store your tank in a location where they could be exposed to excessive heat.  Like, don’t put it on top of your kiln.
  • Never modify or repair tanks.
  • Never leave your acetylene tank in your car.
  • Never throw, drop or abuse your tank. (See, I told you!)
  • Never stand in front of your regulator when turning on the tank.  The regulator can explode from the front or the back so, stand to the side.
  • Never fill your tank yourself – well, of course, if you work for a compressed gas company (or own one) and are trained and authorized to fill tanks, fill away!
  • Never use oil or grease on your regulators or fittings.  In the presence of oxygen, they are flammable.
  • Never use a cracked, burned or crushed hose.  Replace it immediately.
  • Never use any other type of hose with acetylene.  Always use a hose that is designed for acetylene.  It has certain safety precautions built into it.
  • Never lift your tank by the valve cap or stem.
  • Never use your regulator as a lifting or carrying handle.  Hold the tank itself – not the regulator.  You could bend or snap off the, relatively, thin connection to the tank.
  • Never use a regulator designed for one type of gas with another i.e.:  don’t use a propane regulator on an acetylene tank.  Bad idea. The exception to this are disposable gas tank systems, you can switch Mapp gas for propane and visa versa. See the Mapp Gas/Propylene Gas section of this page.
  • Never store your cylinders in an enclosed area.
  • Never use plumber’s tape to fix leaky regulators or hoses.  Tape should never be used to fix a gas leak.  Instead, the regulator should be serviced or tightened further.
  • Never – Leave pressure on a regulator, hose or torch when not in use for an extended period of time.  System should be purged of gas.


Zorch Products: Propane/Mapp Gas Torch System

The Acetylene gas and tank

Chemical compound formula: C2H2.

Acetylene is a gas composed of 92.2% (by weight) carbon (C2) and 7.8% hydrogen (H2).  The reason that the gas burns so hot is because of the mix of carbon and hydrogen. Acetylene is distributed in cylinders or tanks in a dissolved (in acetone), liquid state.  Acetylene tanks can not (by law and common sense) be filled with any other type of gas.

Acetylene is basically, an unstable gas, in that it likes to explode.  So, to combat its socially reprehensible behavior, besides storing it in special cylinders, it is mixed with acetone or DMF.

Acetone, According to the CDC (Centers for Disease Control)  “Acetone may cause adverse health effects following exposure via inhalation, ingestion, or dermal or eye contact.” I recommend not aiming the torch at your face.

Dimethylformamide (DMF) information from the CDC states that the chemical is readily absorbed by the skin and can cause liver damage and other health risks. Getting old is hard enough on those vital organs so I’d avoid covering yourself in Dimethylformamide!

Cylinder Pressure Readings Vs. Actual Contents for Oxygen and Acetylene

The relationship between your cylinder’s contents and what the psi is, in the tank, varies with the gas.  Oxygen has a direct correlation between contents and pressure:  a full tank of oxygen, at 70°F,  (244 cf) shows a pressure of about 2200 psi. At half full, an oxygen tank will read half the pressure and will contain approx. half the contents of a full cylinder i.e.:  1100 psi pressure reading with 122cf left in the cylinder. Oxygen tank pressure varies about 4% for every 20°F.

Acetylene, on the other hand, is less precise:  a full tank, at 70°F will show pressure of about 250 psi. But, the pressure reading can jump up or dip down, depending on the temperature.  If it’s 90°F in your studio (get a fan!), you’ll appear to have more gas, if you go by the regulator (315 psi). But at 50 degrees F, you’ll appear to have less: 190 psi.

 The acetylene tank

Untitled-5The parts of a tank setup. (And a lovely drawing, to boot.)

For the History of the tank, see above heading.

Note here!  When you buy your compressed gas tanks or oxygen tanks, you don’t keep that shiny new cannister.  When you bring your tank in for filling, they take yours and give you a filled bottle.  I will bet that it will be nowhere near as pretty as your brand new one is but, that’s the way it works.  Before your gauge indicates that you are out of gas (notice:  I said BEFORE you are out of gas!). Acetylene, in a “B” cylinder, usually runs about $35.00 plus delivery.

Compressed gasses are supplied in cylinders, also called bottles. I am fond of calling them “tanks”.  They are made from either steel or aluminum. Acetylene cylinders are made from steel and, as you will see, often filled with a substance called aga.

The cylinders come in a range of sizes and types. There are many different adaptors available, if your torch setup doesn’t fit your tank. adapter  You should consult with a professional gas supplier on what adaptors to purchase. There are adaptors for hoses, regulators, etc.  If your little torch doesn’t seem to fit on your B tank, know, that there is an adaptor for it. Buying in kits often eliminates the use of adapters.

Identifications on the tank


There are several markings on your tank.  They can be used as clues as to what’s in your cylinder.  You can also check its last inspection date – if you so desire. Cylinder Identification – Adding Up the Clues is a good page to familiarize yourself with these markings.

See also:

Inside Your Acetylene Tank

inside-tank  Here’s the inside of an acetylene tank.  This porous filler (usually “Aga) is used to help stabilize the volatile gas.

“Acetylene can be safely compressed up to 275 psi (they don’t mean you can turn your regulator up that high!) when dissolved in acetone and stored in specially designed cylinders filled with porous material… These porous filler materials aid in the prevention of high-pressure gas pockets forming in the cylinder.” * From Fundamentals of Professional Welding, Sweethaven Publishing.

Never use a tank, that has been lying on its side, until it has sat in an upright position for a while (1/2 hour to 24 hours) The danger in a tank lying on its side is that pure acetylene can accumulate near the valve stem and drain out of the aga.  Also, there’s a chance that the acetylene and the acetone will separate. * Information and tank image from Virginia Tech.

Acetylene cylinders should not be on their sides for more than a few moments.  Transporting acetylene cylinders, on their sides, is not recommended or safe.  Always, always, allow the tank to stand for at least 7 hours up to 24 hours. But, we’ve already covered this I think.  It’s all starting to blur together…

Further notes on keeping your acetylene tank upright from: **Fundamentals of Professional Welding, Sweethaven Publishing:

“Acetone is a liquid chemical that dissolves large portions of acetylene under pressure without changing the nature of the gas. Being a liquid, acetone can be drawn from an acetylene cylinder when it is not upright. You should not store acetylene cylinders on their side, but if they are, you must let the cylinder stand upright for a minimum of 2 hours before using. This allows the acetone to settle to the bottom of the cylinder.”

*Note: they state two hours.  I’ve heard anywhere from “a few minutes” to 24 hours so, it’s up to you what to do.  But, what is known is that the tank needs to be in an upright position, for a while, before use. I think the time for the tank to sit upright may have something to do with the amount of time that it spent on its side but, I’m not positive about this!  Err on the side of caution!

Acetylene Tank Sizes


W-Line Tanks – whatever this means – I couldn’t find any explanation out in interweb land.

  (Image from, The History of Four-cylinder Motorcycle Engines in America by Paul Garson. Note the acetylene tank on the handle bars – sideways too!) (Photos by: Paul Garson and Teddy Pieper).

MC: 13.2″ (34 cm) tall, 7 lbs (3.2 kg), maximum gas capacity: 10 ft3 (.3 m3). Smaller than a B tank. The “B” tank got its name because it was used on buses to supply a source of fuel to run the bus’s lights.  MC tanks were  mounted on the handlebars of a motorbike to run their lights.  Can you imagine cruising along with a live bomb between your arms and right below your face, on a motorcycle?  Shudder, shudder!

B:  19.5″ (49 cm) Ht., 22 lbs (10 kg), maximum gas capacity:  40 ft3 (1.1 m3) I have a B tank.  It’s not too heavy to lift yet, has enough gas to last me many months.  The B tank holds 40 cubic feet of gas.

WQ: 22.5″ (57 cm) Ht., 34 lbs (16 kg), maximum gas capacity:  60 ft3 (1.7 m3).

WC: 33.1″ (84 cm) Ht., 87 lbs (39 kg), maximum gas capacity:  111 ft3 (3.1 m3).

That’s enough – we’ve already gone way past my lifting ability.  There are other (bigger and heavier) tanks:

  • WS/WSL
  • WK
  • WTL

There are also A-Line tanks in sizes:  3, 4 and 5.  Weights range from 41 lbs (19 kg) to 350 lb (9.9 kg). Whoa, big boy!

  Contenti has a chart on tank types and their fittings (what size the connection to the tank is) that is very helpful.

Make sure that your takes outlet matches the intake valve on your regulators.  Here’s my chart:  Compressed Gas Valve Outlet Sizes.

If you want (or need?) to know the filling capacity of various tanks, here’s a fabulous list from  ACETYLENE CYLINDER FILLING – SETTLED PRESSURE Chart.

 What’s going on in the stem?

Thanks to my buddy Tom, who knows a lot of stuff, for the image below:


As Tom recommends, also test the valve for leaks  – when you first pick up your tank (where Tom has indicated). On a personal note:  I have had three tanks with leaking stems, in the past year!

valve-stem 1

  • Acetylene tanks should only be opened a couple of inches – maybe, 2″-3″.  Definitely don’t open it more than 1 1/2 turns. I open mine about 1/8th of a turn.  You’ll know if it’s open enough – your flame will burn well.
  • Acetylene flame temperatures

    Acetylene mixed with oxygen burns at 3,480°C (6,296°F).  When mixed with air it burns at: 2,500°C (4,532°F).  It is the third hottest gas after Cyanogen and Dicyanoacetylene. Acetylene’s range for combustion with oxygen, to ignite, is from 2.5% – 100% (according to the MSHA).

    *Note: The Department of Mineral Mining (Virginia) states that the temperature that Acetylene and Oxygen burn at are: 5700 degrees F.  Without O2, they list 4600 Degrees F.  So, who knows, it’s hot either way!

    *** I give up searching for the “facts”.  It seems that each, of the several sources that I referenced,  has something slightly different to say.  The message is clear to me,  no matter what the numbers:   Acetylene is hot and flammable.  The end (of my research – for now).

Tools, fittings, regulators and more

Tank wrenches for opening, closing, adding and removing fittings

To open/close your gas stems and connections, you can use an adjustable wrench or a universal tank wrench.  But, for opening the cylinder valve, if it doesn’t have a knob, use a Tank Key only!  They’re cheap – keep a few on hand.

  Use a tank key with this type of stem.  Wrenches can strip the stem – making it difficult to shut off in an emergenc.

  Lucky you!  No tank key needed.

tank-wrench Universal Tank Wrench

adj-wrench Adjustable Wrench – very different from a Pipe Wrench.  Don’t use a pipe wrench.  Its teeth can damage the brass connections on your regulator.

tank-key Tank Key

The gas supplier is usually responsible for tank inspection BUT ( this is a big BUT) you MUST TEST THE TANK, yourself, FOR LEAKS:  check the stem (as shown below) and the place where the stem is attached to the cylinder (valve) before bringing into your home, garage or studio. Haven’t I already said this?  Guess it’s important or I’m losing it (again).

Updated: 2/22/17

The Regulator

Regulators are used to, well, regulate the pressure that is present in compressed gas cylinders.  They also show you how much gas you have in the cylinder.  You never want to use acetylene or oxygen without a regulator.

In order to increase pressure to your torch, you’ll want to use a regulator – for whatever type of gas you are using.

Regulator Types: Stages

Regulators come in three basic types:  three stage, dual stage and single stage. The stages are internal so, a dual gauge regulator is not necessarily a two stage regulator. But, I have yet to find a two stage, single gauge regulator.  If you know of one let me know!  Basically, the dual stage regulator supplies a more constant delivery pressure while a 1 stage regulator may require adjustment during (especially long term) use. The three stage can handle high supply pressure (up to 3000 psi) and provides a stable, low output pressure.  Here’s some information and a comparison of two types from Air Liquide Specialty Gases.

If you are using gas in a cylinder, with its gradually decreasing pressure, it is best to use a dual stage regulator to keep the pressure steady.

Single stage regulators are much cheaper but, unless you do short term soldering tasks, the pressure will fluctuate especially as the gas in the tank gets depleted. You will be fiddling with controls!  I know that I prefer a 2 stage (dual) regulator for metalsmithing and I believe glass bead makers do too.

If you are purchasing a soldering/welding kit, all the connections will match.  But, if you aren’t, you’ll need to match your connections for the regulator, hose and torch handle.  Make sure that the outlet sizes match the inlet sizes. Phew!

For more information, check out these sources:

single-stage-goss-acetylene-regulator  This is a single stage regulator from Goss. As you can see, it only shows the amount of gas/pressure in the cylinder.  But, it is self-regulating. The pressure goes from 2-15 psi for acetylene. To increase the amount of gas, you open it up more.

smith-regulator  There are also flow regulators similar to those found with a small disposable system.  Smith makes such a system with their Little Torch for disposable tanks, product #23-1014.  These regulators adjust the amount of gas entering the line without gauges.

Updated: 2/23/17

The Terminology, Construction And Functions Of Regulators

acetylene-regulator-3  A dual stage acetylene regulator.

inlet-gauge  The Inlet/high pressure/operating pressure Gauge (pick a name – any name!)

The Cylinder Pressure Gauge (CPG)

Aka: the high-pressure gauge, the operating pressure dial and the inlet pressure gauge, etc.

The Cylinder Pressure Gauge measures the pressure at the tank/cylinder.  It is the dial on the right side of a double regulator. It regulates the pressure of the gas coming from the tank and allows you to see how much gas is in the tank.

  • To shut off the gas, at the tank (as measured by the inlet gauge), pull/turn the key/knob in a clockwise direction.  After shut off, the gauge should read 0.  It shouldn’t fluctuate.  If it does, see “Things To Be Concerned About“.
  • Remember : don’t stand in front of the regulators when turning on the gas – stand to the side. Regulators have a safety valve and if the pressure gets too high, it can blow.  Also, the front and back of the regulator may blow out.  I’ve never seen this or heard of it happening, personally but, I believe those, trusted sources, who say this is possible!
  • To open, turn in a counterclockwise direction.
  • Propane and Oxygen tanks close in the same manner.
  • Oxygen and Acetylene should be “cracked” before hooking up the regulators. Open the cylinder valve for a split second and then close it. This blows out any crud or dirt in the valve outlet so that it doesn’t get in the regulator. Wipe the exterior of the outlet, after closing the valve.  Be sure to use a clean, oil or grease free cloth.
  • For fuel gases, like propane and hydrogen, just wipe out the valve with a dry cloth. Do not “crack” the valve as the gas may ignite from friction or other heat source and the hydrogen can catch fire just from the pressurized release.

outlet-regulator The outlet/working pressure/low pressure gauge.

 The Working Pressure Gauge (WPG)

Aka: The low pressure gauge and the outlet pressure gauge, etc.

The outlet pressure gauge, allows you to adjust the amount of gas/pressure that is entering your hose and torch handle.  Turn it down for less gas and up for more.  Don’t forget: never over 15 psi on acetylene!  Sorry about the repetition but, it’s important!

  • To release the diaphragm and stop the flow of gas to the hose and torch, turn the bar counterclockwise.  Release the gas in the hose and in the torch by either opening the torch or opening and lighting the torch. The pressure should now return to 0.
  • To allow gas to flow, turn the bar clockwise.

You should shut off your tank, release the diaphragm and drain the gas from your system, each time you stop for the day or night.  This reduces wear and tear on the diaphragms and the gas is safer inside a closed tank.  Image what would happen if a mouse started chewing on a gas-filled hose?  Hmmm? See this section for shutdown instructions.

On the terminology and myriad names for these gauges:  I like the inlet and outlet pressure terms because they are simple and clear:  inlet measures the gas coming in from the tank, outlet measures the gas going out of the tank!  Violá!

Special Information

  • Gas Regulators (left hand threads – grooved fittings) are threaded in the opposite direction than those for Oxygen tanks (right hand threads – smooth fittings) – that’s so you don’t try to put the wrong regulator on the wrong type of tank.  Did you completely ignore the red and green coloring system? Perhaps you aren’t having the best day? Don’t worry, it would be tough for you to screw this up.  But, if it’s that bad of a day, perhaps you shouldn’t be soldering???

Checking For Leaks

  • Never ever, never, never ever use plumbers tape to fix a leak or a loose connection!  If you detect a leak: Turn off the gas, drain the line – without lighting the gas – re-tighten the connection.  Turn on the gas and check again (see the soap test in the following paragraph and probably in 10 other places on this page.  I get confused, you know).
  • Make your first check with only the inlet gauge activated (turning on the gas at the tank).  If there are no leaks, then tighten the outlet gauge and check all connections related to it.
  • leak-checks  Check all joins, that are not solid pieces, with a mixture of dish soap (2 parts) and water (1 part). Very, very gently stir the soap and water – you don’t want to make bubbles.  Paint the soapy mixture on a join, wait and watch.  If there is no bubbling action, move to the next join.  leak-testing  (Gas leaking from a connection.  Photo from Virginia Tech.
  • You might want to wash off the soap with a damp rag, afterwards.
  • Check the hose connections at the flashback arrestor on the regulator (you do have one, right?).   check-leaks-at-torch-and-hose  Now, check the hose connection at the torch handle for leaks.  Inspect the hose, while you’re at it.  Ensure that the torch head is tight too.

Some notes on Regulators and Tanks

  • Never use grease, lubricants or oils on any part of your torch, tank, hose or regulator – especially with oxygen:  oxygen likes to blow up when in contact with oil or grease.
  • *Note:  Turn off the gas, drain your hoses and bring your regulators in for servicing if you have any question about the safety of them, (i.e.: popping,  unusual fluctuations, weird behavior). If you are mobile with your tank i.e.: taking your tank to jobs sites, you should be especially vigilant because your regulators, hoses and tanks are experiencing much more wear and tear.  If you use them outside, sunlight and weather can further degrade your system. Use T hoses whenever possible.
  • Always get used regulators checked out.  Chances are, they need to be refurbished.  It doesn’t cost much (maybe $35.00 or so) and it is SOOOOO worth having a safe torch and a long life – see car explosion images above for cost effectiveness.  Speak with your gas supplier on when to schedule maintenance.
  • You can use an Acetylene regulator with LPG gases BUT you can’t use a LPG regulator on an Acetylene tank. See Smith Equipment FAQ below.
  • Oxygen regulators should only be used with Oxygen and never used for fuel gases.  Gases can contaminate the regulators.

For Further Research on Regulators:

Check Valves

Check valves stop the backflow of gases but, not flames. Check valves are usually installed at the torch.

The following quote is from Airgas, on the difference between check valves and flashback arrestors:

“For torch and regulator applications, Check Valves guard against danger caused by plugged tips, over-pressurizing or incorrect startup procedures. Proper Check Valve installation helps prevent accidents caused by gases mixing in hoses, regulators or cylinders. Welders rely on Flashback Arrestors to help prevent serious incidents caused by reverse gas flows or flashbacks. Flashback Arrestors are designed to stop flashbacks by preventing ignition of mixed gases and to protect equipment such as hoses, regulators and cylinders.”

Storing Your Tanks

Attach your acetylene tank to a stable object at two points – don’t secure anything to the stem or regulators – there’s a risk that, if the tank falls, it can snap off the stem or the regulators.  I use a heavy chain but, just read that it should be insulated chain.  Whoops. You can also use straps to secure it to the wall or a heavy piece of furniture.  Don’t use bungee cords. See my illustration of an acetylene tank for location of chain or straps on the tank.  Don’t forget to make the chain/strap removable or you’re going to have a lot of fun, when it’s time to refill the tank!  I use clips like these (see below) to make it safe and removable.

carabiner-clip Carabiner Clip  – for clipping the chain to the “O” hooks screwed into the wall. Mine are 2″ long.

Screw-eye Eyebolts:  The one I use is about 3 1/8″ X 3/4″.

Here’s my setup:

acetylene-tank-safe-storage Chained at two points to my cabinets.

oxy-acetylene-kit  (Smith Complete Little Torch)  This system comes with its own storage system.  Another option is the Gentec Torch setup.

According to OSHA: “1910.253(b)(2)(ii)

Inside of buildings, cylinders shall be stored in a well-protected, well-ventilated, dry location, at least 20 (6.1 m) feet from highly combustible materials such as oil or excelsior. Cylinders should be stored in definitely assigned places away from elevators, stairs, or gangways. Assigned storage spaces shall be located where cylinders will not be knocked over or damaged by passing or falling objects, or subject to tampering by unauthorized persons. Cylinders shall not be kept in unventilated enclosures such as lockers and cupboards.

Rio Grande has this to say about tank storage:

“Store all fuel and oxygen tanks safely in an appropriate carrier or securely chain them to a wall to reduce the risk of valve damage that could potentially cause a dangerous release of compressed gas.”

Flashback Arrestor

flashback-arrestor   These flashback arrestors are for the torch end.

smith-flashback-arrestor These Smith flashback arrestors are for the regulator.

Why have a Flashback Arrestor?  Occasionally, the flame (and/or gas) from the torch will find its way into the torch handle or even the hoses.  This is a great way to get killed and blow up your home or studio. Often, a flashback is caused by operator error. Being humans and therefore, extremely fallible, we need backup systems to protect us from ourselves. There is also the issue of equipment failure. Since we usually don’t know about these failures in advance, it’s a good idea to have protection from this scenario too. Flashback Arrestors restrict the backwards flow of gases and flame (from reaching the pressurized, explosive gas in the cylinder!).  There is also a “flame barrier” in the arrestor that keeps the flame from going any further.

The Smith brand, Silver Smith (TM) torch (for hobbyists and jewelers) or their Handi-Heet (TM) torch (Industrial)* does not need flashback arrestors or check valves at the torch handle.  It is a good idea to have an additional flashback arrestor at the tank though.

Flashbacks often present with a popping or high-pitched squealing sound. Turn off the gas at the tank immediately. Purge your fuel lines before re-lighting.

Although, I’ve had squealing sounds coming from the tip of my torch.  It was a bit of schmutz and I’ve also had a drop of water changing the flow of gas and making a god-awful noise.

Backfires are accompanied by a loud pop.  This happens when the torch handle is turned off and the torch flame burns back into the torch and extinguishes.

“Backfires are caused by improper gas pressures; the torch tip touching the work to molten metal; an incorrect, loose, overheated tip; or dirt on a connection or one of the seats” (from Linde Canada).

Here’s a good video of how flashback arrestors work by BOC:  Keeping Safe With Flashback Arrestors.

Here’s an article: A Commentary On Backfires, Flashbacks and Flashback Arrestors by David Gaily at Harris, A Lincoln Electric Company, on flashback arrestors, discussing the differences between the torch mounted and the regulator mounted.

The Hose

  • Check hoses every day for wear and tear.
  • Replace hoses every four years. *
  • Keep hose away from sparks and flame.
  • Keep hose away from pickle, flux, hot metal, hot solder.
  • Red is for gas.  Green is for oxygen.
  • Replace burnt, cracked or damaged hoses immediately.
  • Oxygen and fuel gas hoses are NOT interchangeable.

02 hoses are green and gas hoses are red.  oxygen-and-acetyelene-hose  Forney acetylene and 02 hose. Black hoses are for inert gasses.

The material the hose is made from needs to be compatible with the gas that it carries.  This is to avoid degradation of the hose and resulting hazards.

What gases to use with which grades:

  • Acetylene – use only R, RM or T grades.  R and RM grades can only be used with Acetylene.
  • Most Fuel gases (includes Acetylene and Propane) – use T grade.

Hose Grades – details

  • R grades – the cover and the interior tube, are not oil or flame resistant.  When exposed to oil the hoses can get gummy and degrade.
  • RM grades – the cover IS flame resistant but it is not oil resistant. When exposed to oil the hoses can get gummy and degrade.
  • T Grades – flame and oil resistant.  The cover is self-extinguishing.  There are T grades that have been made even safer by making thicker covers to prevent flying slag and dragging from damaging the hose. They are called welding and scarfing hoses.  T grades are more expensive than R or RM.

Always bleed your hoses if not in use for 30 minutes or more to extend their life and reduce risk.

For further research:

The Torch

The torch is the final stage in controlling the amount of gas that is used.  You can adjust the size of your flame and the amount of heat generated, by adjusting how open the torch is.


  • Don’t use handles designed for other gasses.  Use propane equipment with propane, acetylene equipment with acetylene, etc.
  • Don’t switch torch tips i.e.:  don’t use a Goss tip with a Smith handle.  I had an experience with using the incorrect torch tip (the tip looked just like the Smith torch and was in a box with a variety of other tips) for the torch at school and it resulted in a ball of fire.  My quick-thinking friend David, turned off the gas supply immediately,  probably saving my life and those of the other students. It left a black handprint on the wall where the fireball (complete with soot) blew over my hand.  Ugh!
  • Don’t light your torch with a cigarette lighter or matches – use a striker (electronic or manual). Want burned hands?

What’s inside the oxygen/acetylene torch?

This:  inside-a-oxygen-gas-torch

This is a very simplified illustration of what happens in the oxy/gas torch.

With a gas/air system, the surrounding air is pulled into the mixing chamber (or mixing head).  smith-silversmith-torch-tip  The Smith Silversmith torch tip has holes to facilitate the intake of air.  My Goss, has an “area” (don’t know what to call it!) that sucks in air. goss-torch-head

Torch Tips

This part is just not done.  My neck hurts and my feet are numb so, I’m quitting for now.  With any luck, I’ll remember to come back and finish this section!  Need a lot of luck and perhaps a memory too. Actually, my memory is so bad that I didn’t realize, until this moment, that I have another page I’m working on, that is about torches.  Geezzz… Guess I won’t work on this section anymore!

You’re gonna need a torch tip for that torch!  What you are doing, will determine the size of the tip.  If you are welding together an exact replica of the Statue of Liberty,  statue-of-liberty please use a large torch tip.  If you are soldering prongs for a setting, let’s think a bit smaller.

Each torch has a set of torch tips designed specifically for use with it. Don’t use tips from another type of torch.  Did you read what happened to me? If not, please go back and read my tale under:  The Torch (above).

I basically use one tip, almost all the time.  It gives me a largish flame which, is tricky to solder tiny things with but, I’m a “hurry up and let’s get this done”, kinda girl.  If I were smarter, I would use at least two tips:  one for small work and one for the rest. I actually own about 5.  I have used the teeny, tiny tip a few times but, it blows out when I move my hand.  I have also used my largest tip for melting gobs of metal.


As mentioned earlier, if you are soldering gargantuan pieces of jewelry, you might want a third, larger tip.  Also, large tips come in handy for refining metal.

In summary (at least for today), have 2-3 tips around for a variety of uses.

Using your system

Starting Up Your Torch

Please see mine and Chimera Art’s video on the safe use of an acetylene torch and tanks.  In it, I show you how to turn on your gas, regulators and torch plus, how to turn it all off again!  Very important safety information is covered.  (Image from Virginia Tech: Compressed Gas Cylinders Equipment.)

Stand to the side, of the regulators, when turning on the gas and adjusting the outlet and inlet pressure.  There is a very remote chance that the regulator will blow out. The only images that I found on ye olde interweb, was the one above and this one from Air Products EXCELLENT PDF (read it). I also didn’t find any stories about this happening.  So, I guess it doesn’t happen too often but, why play with fire (so to speak). What can happen is that the gas can leak into the regulators.  Acetylene, when allowed to collect in a contained space, is extremely volatile and is eagerly waiting for a small spark to create a big blow. See exploding car photos and the photo above for evidence of this fact.


  • When first turning on your tank, check that the diaphragm is open on the Outlet (left side of regulator – see below) FIRST! If it isn’t, drain the gas from the hose by opening the torch, lighting the gas and burning off the excess (for gas/air systems only). Check that gauges are reset to zero (like in the image above).
  • Now, turn on the gas with the key or the torch wrench.  Push the key/wrench backwards in a counterclockwise movement – a quarter of a turn or 2″-3″.
  • The first time you open your tank, it might be very, very tight.  You might need to find a strong man or woman to open it for you.  After the initial opening, just turn the tank off – by hand tightening. To ensure that you shut it tightly enough, check the gauges – after draining the hoses – the gauges should read zero. When tightening:  remember, you don’t want to call someone for help every time that you turn on the gas!  There is a balance between too tight and not tight enough.  An indicator of your effectiveness at shutting it off is; the gauges remaining at zero.  If the gauge slowly starts to move, it’s not shut completely.  It might take a few hours for this to occur so, check a few hours later. Movement within the regulator means you have gas leaking into them. Not a safe situation. I would check often during your first few days of use – until you start to understand your system fully. If you don’t have the strength to turn the cylinder off, you will need help.   Perhaps look into a different type of key or wrench.
  • On initial opening: I recommend that you “crack” the cylinder before putting on your regulators.  Then, using hand strength only, reclose the cylinder and set up the regulators.  Opening the tank first, before the regulators are in place, allows extra room for leverage. It also discourages ole’ Bruto (your overly macho cousin) from using the regulators as part of that leverage.  We don’t want undue pressure on our regulators; they can bend or worse.
  • gauge-inlet-open-outlet-shut  Moving on:  You should now see the gauge go up, on the right but, still be at zero on the left – as in the photo above. Tighten regulator adjusting screw (the turning thingy may be a knob or a bar), clockwise, to allow the gas to flow to the hoses. Turn until the pressure, on the outlet regulator, measures 10 – 15 psi. Do this slowly and watch where the needle moves on the dial.  I may have said this 50 times but, I’ll say it again:  Never, ever go past 15 psi!  Ever!  See the: Never Section in this page. If you accidentally go too far (don’t do that – take your time), turn it back down and release a little gas. Check the gauges: Are they stable? No dropping or rising of pressure?  Great! You’re set and ready to start soldering!
  • Wait:  no long, dangly sleeves, long hair tied up, protective glasses, cats cleared out of the area? Of course!  Close-toed shoes? Check. Ventilation in place? Check, check. Fire retardant/proof surface in place? Yup. All flammables removed from the area?  Yes mother.  Okay, GO! Light that torch!


Inlet and Outlet pressure open and just waiting for you to start soldering!

Shutting down your torch

  • Shut your tank down everyday – after you are done working of course! THEN drain the gas from the lines.  I turn on the torch (the thing with the tips that the fire comes out of!)  and light the gas to do this.  The gas only burns for a few seconds and then goes out.  Line drained!  Don’t forget to shut off your torch handle and release the diaphragm on the regulator (the one on the left).
  • If you use oxygen AND a gas, don’t burn off the gasses, as with just acetylene and air: just shut off the gas supply at both tanks.  Open the oxygen part of the torch handle and drain the 02. Next, open the left side of the oxygen regulator, releasing the pressure on the diaphragms. Ventilate.
  • Here’s your END OF DAY LIST:  Inlet regulator – tank off, hoses drained, outlet regulator – open.  Post this list near your light switch or near your soldering area.  While you are at it:  Turn off the pickle pot!

Opening and closing down an oxygen/gas system

Oxygen-regulator-2  Oxygen regulator by Victor.

  • To shut off an 02/gas torch, turn off the oxygen first and then the gas.
  • Conversely, to light an 02/gas torch:  turn on the gas and add 02 until you attain the flame type and size that you want.  With the Smith Little Torch’s smaller tips, you’ll need to add O2 VERY, VERY SLOWLY or the O2 blows out the flame.  Also, once the torch is lit, adding too much oxygen will blow out the torch.  Annoying, yet understandable.
  • When using an 02/gas system you will have two sets of regulators.  Oxygen regulators will have smooth inlet fittings and usually have green somewhere on them.  Gas regulators will have red and the fittings will be grooved.

smith-regulator-oxygen smith-regulator

The Smith Little Torch Preset Oxygen Regulator is green with a smooth inlet fitting.  The Smith, Stage 1 Propane Regulator has a groove in that thingy, that I think is called a nut.

Oxygen tanks should be stored separately from the gas tanks.

Other Gasses

Mapp Gas and Propylene Gas

Thought I’d throw this in! Who doesn’t like a little more information of gas?

Mapp gas is no longer being produced.  Although, you may still find it in stores.  The new gas: Mapp-Pro is actually Liquified Petroleum Gas (LPG) with a large amount of  Propylene gas. Propylene can be found at gas suppliers in larger tanks.  I just spoke with Airgas, and the man I spoke with stated, that you have to rent the tanks.  Airgas sells a kit to use with the rental tanks. You also need special tips for the torch. The salesman at Airgas said you could use propane hoses but, they won’t last very long.  He recommended using the hoses designed for the gas.  Mapp gas, when mixed with O2 can reach temperatures of 5300 °F (2925 °C).  For comparison, Acetylene and O2 can reach  5720 °F (3160 °C). But, it’s only a 420°F difference.  This is plenty hot for silver soldering!

Updated 2/23/17.

If you have a torch kit for disposable Mapp/Propane tanks, you can use that with the Mapp-Pro.

Mapp-Pro burns at 3,730 degrees F while propane burns at 3,600 degrees F.

Here’s a quote from Praxair on Propylene gas:

“When compared with acetylene, propylene offers greater safety as it can be utilized up to full tank pressure. It is well suited to being used at cold temperatures as it has a greater vapor pressure when compared with propane.”

Victor Technologies has an entire page on this subject.

The Smith Little Torch can be used with disposable tanks.  The torches are made to work with Mapp (propylene), propane and O2 disposable tanks.  You will find that you will use more oxygen tanks than gas so, buy extra.  As of this writing, there is no recycling system for the empty canisters – I called the manufacturer.  This is of some concern to me because it all gets dumped into landfill or elsewhere.  So, consider this before purchasing a disposable system.  But, sometimes, a disposable system is all that you can use – due to restrictions on your studio space.  The portable system is also great for classes and for teaching.  But, the portable system is more expensive than the tank setup. Many things to consider!  Note:  IF you purchase the Smith Little torch for portable tanks, and you decide you want larger tanks, down the road, you can just take off the fittings, on the ends – the ones that adjust for the disposable tanks. Don’t use propane regulators, hoses or torches with acetylene.  You can use propane hoses and torches but not the regulators with acetylene.

Updated: 3/21/18, 2/23/17

Related Videos

Required Reading (IMHO)

Air Products:  SafetyGram – 13.  Acetylene. This is a very precise document and goes into more detail and with more technical information than my page presents.

Bibliography and For Further Research

  1. (n.a.) History:  “Acetylene Dissolved in Acetone”. Retrieved:  January 30, 2015. Website:
  2. (n.a.) “History: Gustaf Dalén”. Retrieved:  January 20, 2015.  Website:
  3. Air Products.  (Rev. February 1994) “Safety Gram-13, Acetylene (Pub. No. 310-721)“. Retrieved: January 29, 2015.
  4. Almqvist, Ebbe . (2003) “History of Industrial Gasses” Vol. XVIII. Springer Science & Business Media. Paris, France (?). Retrieved:  January 30, 2015.
  5. Benes, James of Welding Design and Fabrication.  (March 19, 2007) “A heads-up on hose and regulator safety“.  Retrieved:  October 2014-December 2014.
  6. Bensaude-Vincent, Bernadette for Encyclopedia Britannia. (October 29, 2013). “Pierre-Eugène-Marcellin Berthelot“. Retrieved: January 30, 2015.
  7. Bhatia, A., Fundamentals of Gas Cutting and Welding. Retrieved: 3/21/18.
  8. Compressed Gas Association (CGA) “Pamphlet G-1 2009”. Via: Web.  Retrieved: December 2, 2015.
  9. Erickson, Lexi.  (2007). “Set Up Your Torch”.   Retrieved:  December 2014.  Retrieved: October through December 2014. Ganoksin via Lapidary Journal Jewelry Artists Magazine:
  10. ESAB. (No Author, no date) Handbook – Oxygen and Acetylene.  Retrieved:  March 21, 2018.
  11. Heiserman, David L. Editor, Sweet Haven Publishing Services. (Revised: December 03, 2014).“Fundamentals of Professional Welding“.  Retrieved: January 29, 2015.
  12. Nobel Lectures, Physics 1901-1921. “Gustav Dalén – Biographical“.  (1967).  Elsevier Publishing Company, Amsterdam. Retrieved:  October 2014.
  13. Nobel Lectures, Söderbaum, H.G., Professor. (December 10, 1912). “Award Ceremony Speech“. Retrieved:  October – December 2014.
  14.  Today in Science History. (1999). “Edmund Davy“. Retrieved: January 30, 2015.
  15. Victor “Training Content by Category“. Retrieved: January 29, 2015. Victor
  16. For a WOW moment check out: Even a small cylinder of acetylene can do a LOT OF DAMAGE…, Mike Schlags, My Firefighter Nation. Retrieved:  9/16/15. Web. 12/17/2009.
  17. Division of Mineral Mining, Virginia: Oxygen and Acetylene Use and Safety – a really good resource with lots of pictures!
  18. Tractor Supply Company. How to Select and Setup a Oxy-Acetylene Welding Rig. Retrieved: 9/16/15. Tractor Supply Company: Web.  Date published: unknown.
  19. United States Department of Labor.  Osha: Oxygen-fuel gas welding and cutting. Retrieved:  9/16/15. Occupational Safety & Health Administration – OSHA:  Web. Date published:  unknown.
  20. Rio Grande.  Rio Grande:  How To Safely Set Up An Oxygen/Propane Torch. Retrieved: 9/16/15. Rio Grande: Web video. Uploaded: 3/30/11.
  21. Weldcor: Encyclopaedia of Terms: OXYACETYLENE WELDING (OAW).  Retrieved: 9/17/15. Web. 2013.
  22. Karen Christians Clever Werx. Soldering Fundamentals. Retrieved: 9/17/15. Web. Date published: Unknown.
  23. Matheson: Guide to Regulators. Retrieved: 9/17/15. Matheson Gas:  Web. Date Published: 2014.
  24. California State University: Fullerton.  Environmental Health and Safety: Gas Regulators. Retrieved: 9/17/15. California State University: Fullerton: Web.  Date published: unknown.
  25. The Compressed Gas Association (CGA).  You can purchase publication TB-3 on Oxy-Fuel Hose Line Flashback Arrestors (or become a member and they are free) and SB-16: Use of High Flow Oxy-Fuel Gas Heating Torch Apparatus. They have many, many articles, bulletins, videos, libraries and safety alerts.
  26.  **Fundamentals of Professional Welding. David L. Heiserman, Editor. Sweethaven Publishing. Free-Ed Net: Retrieved: 9/17/15. Web. 6/6/15.
  27. OSH: Answers Fact Sheets. Compressed Gases – How Do I Work Safely with. The Canadian Center for Occupational Health and Safety. Retrieved: 9/17/15. Web. July 8, 2008.
  28. Silversmith and Handi-Heet torch manuals. Smith Equipment.  Retrieved: January 29, 2015. Web. July 2013.