Fun with Fire: Oxy-Acetylene Basics

If generations of Hollywood heist films have taught us anything, it’s that knocking off a bank vault is pretty easy. It usually starts with a guy and a stethoscope, but that never works, so the bad guys break out the cutting torch and burn their way in. But knowing how to harness that raw power means you’ve got to learn the basics of oxy-acetylene, and [This Old Tony]’s new video will get your life of crime off on the right foot.

In another well-produced video, [Tony] goes into quite a bit of detail on the mysteries of oxygen and acetylene and how to handle them without blowing yourself up. He starts with a tour of the equipment, including an interesting look at the internals of an acetylene tank — turns out the gas is stored dissolved in acetone in a porous matrix inside the tank. Working up the hoses, he covers the all-important flashback arrestors, the different styles of torches, and even the stoichiometry of hydrocarbon combustion and how adjusting the oxygen flow results in different flame types for different jobs. He shows how oxy-acetylene welding can be the poor man’s TIG, and finally satisfies that destructive urge by slicing through a piece of 3/8″ steel in under six seconds.

We’ve always wanted a decent oxy-acetylene rig, and [Tony] has convinced us that this is yet another must-have for the shop. There’s just so much you can do with them, not least of which is unsticking corroded fasteners. But if a blue wrench is out of your price range and you still want to stick metal together, you’ll want to learn how to braze aluminum with a propane torch.

28 thoughts on “Fun with Fire: Oxy-Acetylene Basics

  1. I love This Old Tony and AvE. They are hilarious and informative like Bill Nye in the 90’s. But can you please try to find other sources of material? Writing an abstract to a video by a “good ole standby” seems lazy and is annoying.

    1. We all needs this kind of attitude. If you can’t do something all by yourself, steal what someone else has done and milk it instead.

      Arduinos

      Open Source

      HaD articles

      China

      We almost got a movement going here!

    2. Congratulations, you already knew about this.

      I (with some very minor experience with oxy welding) did not know about this until the article was published, and I’m grateful for the pointer.

      So, please get off your high horse and if you’re already familiar, feel free to skip the article.

  2. Silver solder, brazing, welding steel, welding aluminum, cutting steel…
    It’s amazing just how useful the OA torch is and how much it can do. And then LOX and an Acetylene generator make for a very portable and long running rig compared to bottled gas.

  3. Sorry, but I have to go all safety nazi here, but everyone who ever talks about using compressed Oxy needs to say this:
    NEVER, ever, ever use any sort of grease or lubricant or sealant on your Oxygen connections.
    This is one of those cases where common sense will get you killed.

      1. For low pressure you can use silicone grease IF it is oxygen approved. Common on the low side of scuba pressure regulators. DO NOT USE ANY silicone grease on the high pressure side. Oxygen approved or not.

    1. I used to use o/a all the time and never knew this.. only reason i dont have a set now is my insurance wont let me due to glats sharing a common wall with my workshop. Thankyou for the post. I still use burning gear occationally in others workshops.

    2. I have been cleaning my brass threads on my regulators with acetone before assembly to ensure there is no grease or oil and then using thread tape. After cleaning I let it sit for 30 minutes or so to ensure all acetone has evaporated prior to assembly. See any issues?

  4. For the home user (certainly in the UK) you’re supposed to let the fire service know (there may even be an official register – sure there is for businesses using any compressed gas or hazardous substance) and your home insurance would most likely wish to be informed.

    While this stuff is neat and has many uses, it’s about half a step down from keeping a live bomb in your house. Some might consider the risks outweigh the benefits when you can buy electric welders and plasma cutters reasonably cheaply these days and achieve almost everything by some other means, with lower fire risk and no need to rent bottles etc.

    For a while we used oxygen + propane which works almost as well, is easier to come by, and less dangerous to store, but when it ran out we didn’t bother replacing it – we had a welder, a plasma, grinders, blowlamps, so there was nothing we couldn’t do some other way with much lower fire risk.

    1. Generally….yes but it can be hard to pass up the flexibility of OA rigs. They can do everything you mentioned somewhat cost effectively (they are consumable after all). The one thing they do really well is getting things hot, I know of no other common industrial gas that can get as hot, even propane is 1000 degrees colder. When time is money that can make a difference.

      Safety is always a concern and if you can afford the bottle rental you can afford to maintain your equipment. Quality hoses, dual flame arrestors (torch & bottle end) and quality regulators. Not to mention a solid trolley or better still chained to a wall. I have been around the fabrication industry for 30 years and have not even heard a horror story of an OA accident.

      I think you are right on the money for home users though.

  5. We used to use our OA rig for heating in the workshop. After using a bottle for a while it would “pop pop pop” and blow out. We called someone in to investigate why and it turns out for the type of heating we were doing the G size bottle was extremely inadequate, in fact we would have needed the equivalent of four of them to safely use the rig for heating with the size tips we were using.

    If the bottle is too small for the tip you are using the stabilising acetone can leach out of the bottle and make it unstable.

    So my point is make sure you also size your bottle to your nozzles. We have switched to an LPG torch for heating and use the OA rig for cutting only. Sorry no references for further reading, just my 2 cents…

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