An End to Raggedy Torch Cuts
Many of us are comfortable using an oxy-acetylene torch, but sometimes we’re dissatisfied with our cuts. Here are things to check, and tips to improve torch performance:
1. Generic regulator setting for acetylene pressure is 5 to 7 psi. Never set acetylene pressure over 15 psi — acetylene can become unstable and explode at more than 15 psi.
2. For cutting steel, recommended initial pressure for the oxygen regulator is 25 psi, with the cutting trigger tripped. More pressure helps blow through thicker metal, but it can lead to ragged edges on thinner metal.
3. More or less heat for cutting thicker or thinner metal can be obtained by adjusting oxygen and acetylene pressures only to a point. Using a tip of the correct size plays a big role in clean cuts. There are charts on the internet that recommend what tip to use when cutting steel of different thicknesses. For example:
• a #00 tip is recommended for ¼” steel
• a #0 tip is matched to cutting 3/8” to ½” steel
• a #1 tip is preferred for ¾-inch steel
4. Tinted goggles or sunglasses allow precise control of metal temperature and the cutting jet. A tinted face shield not only improves flame control, but protects the entire face from blow-back sparks.
5. Once a cut is initiated, keep the torch tipped slightly — 10- to 15-degrees — toward the direction of motion so the flame preheats the metal before the cutting jet arrives.
6. Keep the tips of the blue heating flames just above the surface of the steel. Those tips are the area of maximum heating.
7. Use a piece of angle iron as a “fence” to create straight cuts. When making circular cuts, a short piece of 3" to 10" pipe can act as a circular guide.
Here are a handful of other stories from ace mechanic Dan Anderson to help you tackle your shop to-do list:
5 Facts to Wipe Away Some Confusion About Dielectric Grease
Not All O-Rings Are Created Equal
3 Special Tools to Drill Large-Diameter Holes in Thick Steel
4 Ways to Deal With Electrical Gremlins
