How to Cut with an Oxygen Acetylene Cutting Torch
You already have your Victor or Harris regulators set and the gas turned on. First turn the oxygen on all the way up, just turn it all the way on and then you just turn the acetylene on a little bit just to light it and then you light with the striker. The safest and best way to light your oxy acetylene torch is to use a flint striker. Basically, this is a device that has a flint member that is fixed into a threaded socket that screws into a spring loaded member that moves back and forth against a hardened steel surface like a file. This assembly is held inside a protective steel cap about 1” in diameter x ½” deep. When the striker is activated by hand pressure, the flint moves across the steel file and creates sparks. These sparks, of course, will ignite the acetylene, and the steel cap will keep the flame from unexpectedly projecting too far. These strikers are made by many companies such as: Forney, Hobart, Ally Tools, Vas Tools, Hot Max, US Forge, Lincoln Electric, Worthington, Levado, and Tech Team https://techteamproducts.com/. Tech Team’s model 763 Flint Striker https://www.amazon.com/Lighter-Igniter-Oxy-Acetylene-Tech-Team/dp/B07NGS8PLY/ref=sr_1_33?crid=2QQKZ0LGHZBCF&keywords=flint+striker+welding&qid=1565098867&s=gateway&sprefix=flint+striker+welding%2Caps%2C124&sr=8-33 is the one we like the best because it has high quality construction with a durable zinc plating, and it contains 3 flints that can easily be rotated one to the next to the next as it wears down and becomes ineffective.
It probably also occurs to you that eventually these flints will wear out and oddly enough there are several companies that make replacement flints such as: Forney, US Forge, Shurlite, Zippo, and Tech Team https://techteamproducts.com/. We happen to like Tech Team’s item 761 https://www.amazon.com/Replacement-Strikers-Oxy-Acetylene-Tech-Team/dp/B07NGNFK2V/ref=sr_1_1?keywords=tech+team+flint&qid=1565108056&s=gateway&sr=8-1which contains 3 sets, each set having 3 replacement flints, which easily fits into their 763 3 Flint Striker. These can usually be purchased from Lowe’s, Home Depot, Allied Welding Supply, or online from Amazon.
Before you begin to cut you should mark where you want to cut. Frequently when you are using a torch to cut metal, you need to mark where you are going to cut. There are lots of ways to make a mark or a line that range from using a magic marker or sharpie, or just scratching the metal with an awl. The best way to make the marks you need is to use soapstone, which is the solid form of the same talc that is used in talcum powder. The handiest way to do this is to use pre-cut rectangular (127 x 12.7 x 4.8mm) prismatic pieces of talc, which are held in a special pen shaped device with a pocket clip that allows the talc to be firmly held and advanced as the talc wears down. These soap stone holders are available from many companies such as: Forney, Ally Tools, Hobart, Firepower, and Tech Team® https://techteamproducts.com/. We happen to like Tech Team’s model 759 the best https://www.amazon.com/Soapstone-Retractable-Oxy-Acetylene-Tech-Team/dp/B07NGJ4MB1/ref=sr_1_3?keywords=tech+soapstone+holder&qid=1565098360&s=gateway&sr=8-3 because it has a durable zinc finish and a positive locking and advancing mechanism for the soap stone.
Of course, you also need soap stone, aka talc, to feed the holder as you wear out the soap stone. Those refills are available from several companies such as: Homee, Anchor, VasTools, Uniweld, Hobart, and also Tech Team® https://techteamproducts.com/. We like Tech Team’s 757 36 pc. of soap stone https://www.amazon.com/Tech-Team-Soapstone-Machining-Surfaces/dp/B07JMFBFW3/ref=sr_1_44?crid=13B5M9FVHOOXU&keywords=soap+stone+holder+welding&qid=1565097627&s=gateway&sprefix=soap+stone%2Caps%2C128&sr=8-44 the best because it is high quality, bright white soap stone that leaves clear and easy to erase marks on almost any metal surface.
If there’s a lot of black smoke coming out just turn the acetylene knob until the black smoke barely stops and then you adjust the oxygen knob so that it lets the oxygen out and you want to just turn it until that outer cone gets shrunken down to a point. Then you want to push that lever so the flame is the same size as when you don’t push the lever.
Now how to use a torch. After you preheat you want to hold the flame ½ inch off and then when the steel gets molten, push the blast lever and then drag it straight across in a nice fluid, smooth motion, you don’t want to go too fast. What you look for on the edge is how the molten puddle starts.
You want to press the lever right before that, right when it first happens. I wait until I see a little tiny speck of molten metal and then I push the oxygen lever and then just drag it straight across. I can’t really tell you the speed to go, you have to practice, but you’ll get it after a little while. You want to just keep the flame right on the edge, it’s hard to explain, but you’ll get the basics. If you go too fast, it just won’t cook if you go to slow it leaves a bunch of goop coming out the bottom, which you don’t want. But you know it just takes practice to get it where there’s not any slag hanging off. If you go too fast it stops cutting and when you go to slow there’s a bunch of that dingleberry hanging off, but a lot of it will just chip off and you can grind it off, but you don’t have to do that all the time.
When you go too fast past a spot you should wait till you see a little bit of molten metal. Once you get the hang of it, you’ll know when it’s the right time to do it and then you press down the oxygen lever and it’ll cut through. What’s happening is that oxygen is actually burning metal like it’s using the metal as fuel and blowing it right out, catching it on fire, literally burning the steel out and when it’s molten, it’s ready to get ignited by the oxygen. If you go too fast, don’t worry, just hold the flame there again and wait for it to get molten and start over.
To do piercing, like when you just want to make a hole in the middle of metal, it takes longer. What to look for is a little that little dot of wetness, that’s when you want to push the oxygen lever down to make a piercing hole. You just heat it up, it takes a while to pierce thick metal. Especially if you are cutting something like a structural steel I beam or large diameter high pressure pipe. For ½ inch metal you just hold it there and then you wait till you see that little bit of liquid and then you push down the oxygen. You can push it down a little bit before that once you know what to look for. If you push it down too soon, it’ll spray a bunch of metal all over your face and you don’t want that. You wait until it’s molten. As far as shutting down your torch, some manufacturers suggest turning off the oxygen before the acetylene others suggest the reverse. Read all your instruction manuals. If you think I may have left something out you can do a Hey Siri or Hey Alexa search to find some more ideas.