Fire-retardant clothing is recommended but, if that isn’t available, wear close-fitting cotton clothes. Nylon and most other common synthetic clothes will rapidly burn if caught on fire! Sturdy, leather-soled work boots are recommended. Hot pieces of metal, called slag, can easily burn through rubber-soled shoes. Laced boots are preferable since slag can drop into the top of pull-on boots, like engineer’s boots and cowboy boots. You should also have a set of cutting goggles and heavy leather gloves.
Flying slag can easily cause a fire in your workspace, so test your fire extinguisher to ensure it’s in good working order before you start cutting.
Do not allow the flame to contact concrete, especially fresh concrete, as it may cause it to expand and crack violently, sending small bits of concrete flying.
Also, beware of material that has metallic oxide coatings, such as lead paint, chromate primers, and zinc plating, since inhaling the fumes from these can be toxic.
For very precise cuts, you may get better results by using a specialized jig to etch the line into your work surface.
Since the fittings are made of brass and can easily be damaged, tighten them with an appropriately-sized wrench.
At higher than 15 psi (100 kPa), acetylene becomes unstable and may spontaneously ignite or explode.
Opening the tank more than a single turn could lead the gas to become unstable, and it will be harder to turn off in the case of an emergency.
Close the acetylene valve on the torch once you are sure the pressure is regulated.
The setup on top of the oxygen tank will be similar to that on the acetylene tank. The oxygen valve is a double-seated valve. When you open it, be sure to turn the handle so the valve is all the way open. Otherwise, the oxygen will leak out around the valve-stem O-ring.
The valve near the hose connections will control the flow of oxygen to the mixing chamber for the combustion, so no oxygen should vent from the torch tip until either the cutting lever is depressed or the valve further up the torch is opened.
A small yellow flame should appear at the tip when the sparks from the striker ignite the acetylene. Using matches or a cigarette lighter is very dangerous. A striker is a tool made especially for igniting torches, and using one reduces the risk of serious injuries.
If you hear a blowing noise, or the blue flame seems erratic and feathery, there is probably too much oxygen at the flame. Reduce it until the flame is stable and the inner flame is a clean cone shape.
For room-temperature 1⁄4 in (0. 64 cm) plate steel, this should take about 45 seconds. However, it will take longer for heavier material or material at low temperatures.
If no reaction occurs, the metal is not hot enough to ignite. In this case, release the oxygen handle release and continue to allow the flame to heat the metal more.
It’s better to cut too slowly than to try to cut too quickly.
Some models may instruct you to turn off the oxygen before turning off the torch valve. In this case, always defer to the manufacturer’s instructions.
You could also allow it to cool naturally if you aren’t in a hurry. If you’re using quench- or temper-type steels, allow the steel to cool naturally, as water could cause them to warp.
