Cutting Torch Circle Burner? The 89 Latest Answer

Look around. Is there anything – anything – within 25 to 30 feet that could catch fire if, say, a shower of sparks landed on it? Are you sure? what are you wearing Does your shirt have open sleeves, an open collar? Is there a large tongue hanging out of your sneakers, or is there some other opening for a ball of fiery molten metal to roll into?

These are the questions you need to ask yourself when working with an acetylene cutting torch, colloquially known as a blowtorch in grease shops everywhere in the 1950’s. Carlos Dos Santos, owner of Brooklyn Motor Works – where I’m in the process of reviving a particularly dented Toyota Land Cruiser – taught me that in a short tutorial. The message was clear: almost any mistake can result in burns, a fire or – in the worst case – a huge explosion.

The blowtorch is essentially a metal tube that mixes acetylene – an odorless, colorless hydrocarbon gas – and oxygen to create a very hot spot flame. This flame can be used for cutting and welding (although it’s not as efficient at welding metal as arc welding). Acetylene will burn on its own when combined with atmospheric oxygen, but adding pressurized oxygen makes for a much cleaner, almost focused flame. The “blow” part of a blowtorch is that extra jet of oxygen. The mixture of acetylene and oxygen comes out of a small ring of tiny holes in the tip of the torch, and the flame they create melts metal, turning it into a molten slurry. When you pull the flashlight’s trigger to activate the oxygen jet, the extra gas blows the molten metal out of the way, leaving a hole that I hope you intended to put there.

Carlos has been working with acetylene for years and, under the tutelage of old school tough guys, started out arc welding and flaring things with tank tops and other inappropriate clothing. It wasn’t the best example to follow and he said he’s had his fair share of glitches by following their lead.

“How do I know molten metal can roll into your shoe with your tongue hanging out of your pants?” he asked as I stood with his baby-faced apprentice, “Junior, Jr.”, who was also soaking up knowledge. “Because it happened to me. There is no easier way to lose control of your flashlight than when something under your clothing burns your skin.”

Other places for these nasty globules to enter (and which Carlos knows from experience): ear canals, shirt collars, rolled up sleeves. The pain of being singed can cause a temporary loss of control. Imagine this: A lump of hot metal rolls down your shirt. You scream, jump back, and involuntarily flail as it slowly burns your skin. If you release the flare at that moment, it will bounce off and land squarely on the rubber oxygen and acetylene lines. Then? Explosion.

None of this is meant to suggest that acetylene torches are all disasters just waiting to happen. Properly managed and with a lot of respect for the damage they can do, they are very useful tools. It’s just important to remember a few things when using it.

– Always check the area you will be working in for flammable material before lighting the flashlight.

– Make sure the regulators on the acetylene and oxygen tanks are set to the correct pressure (wrong pressure can cause an explosion or fire, surprise surprise).

– Never stand in front of a gas regulator (the thing on top of every tank with the gauges on it). Stand aside. That way, if for some reason it explodes (and you never know), you won’t get in the direct path of flying debris.

– Always be aware of where your oxygen and acetylene lines run. They are almost always paired, with the red connected to the acetylene tank and the green connected to the oxygen (due to different sized connectors, it’s impossible to misconnect the lines). As mentioned, you don’t want molten metal rolling over them and melting through

– Always wear a welding mask. Forget those old movies with guys wearing goggles while they tinker. You want to protect your face from lava spatter, right? Also, your eyes need to be protected from the brightness of the flame, so regular goggles will not suffice.

– Dress appropriately. Wear non-combustible materials such as cotton, wool and preferably leather. Plastics melt with your skin when they catch fire. That’s why combat troops in war zones don’t wear synthetics; dirty cleaning.

– Always have a fire station when you work. Wearing a welding mask protects your face and eyes, but it also limits your field of view of what you are working on. You should have someone behind you to warn you in case something catches fire (very likely) or sparks get near the gas lines.

– Open the tank valves a few turns at a time by turning them counterclockwise (rightey-tightey, leftey-loose). Never open the valves so far that you cannot quickly close them if something goes wrong.

– Adjust the acetylene outlet pressure to 7 psi (but never more than 15 psi). The higher the acetylene pressure, the more unstable and dangerous it becomes.

– Adjust the oxygen pressure to about 15 psi.

– Open the acetylene valve on the burner head a little (you don’t need too much here). Once you hear it hiss at the tip, hit a steel and flint (which produces sparks) strike near the head. The gas catches fire and burns with a flame that is bright orange and jagged and gives off a little smoke.

– Slowly add oxygen with the other valve, turning the unkempt flame of pure fuel into a chiseled point of blue fire. The middle of the flame should be white and the rest shouldn’t be too long.

Now you are ready to cut. How to do it:

– Hold the flame near (but not on) the piece of metal you want to cut. Wait for it to become shiny and lava-like. This means the metal is soft and malleable.

– Once the metal has returned to its volcanic state in front of the flame, carefully add the oxygen jet.

– With the nozzle trigger pressed, gently move the torch over the surface to be cut. The metal should give slightly.

– Take your time! Haste can only cause mistakes, and mistakes can cause big problems.

Any time a project calls for a round hole in a piece of flat stock, look to your portable rotary tool with a circle cutting attachment to get the job done. A circle cutting attachment has a pin in the center of the circle that acts as a fulcrum, guiding the rotating tool around the circle. The result is a clean and neatly cut round hole in the material. The attachments adjust to make holes from less than 1 inch and up to 12 inches in diameter.