Starting from the Edge of the Plate
Edge-starting is relatively simple. Position the torch so that half of the nozzle is over the plate edge, and the other half extends over empty space. Begin heating until the steel reaches its ignition temperature—you’ll see the area beneath the nozzle turn bright red. At that point, release the cutting oxygen jet. This initiates the oxidation reaction and the torch can begin moving along the cutting path.

Starting from the edge is easier because the ignition temperature is reached more quickly, and there's space for slag and molten metal to escape cleanly from the cut zone.

Piercing from the Surface of the Plate
Piercing directly into the surface is more challenging, especially with thicker plates. It takes longer to heat the material to ignition temperature because heat dissipates more quickly into the surrounding metal.

The biggest issue during piercing is slag and molten metal buildup, which has nowhere to escape. This causes excessive splatter, leading to nozzle clogging and interruption of the piercing process. For this reason, oxy-fuel piercing is limited by plate thickness, and the maximum thickness depends on the specific equipment and manufacturer.

Piercing Technique to Prevent Nozzle Clogging
To successfully pierce steel with an oxy-fuel torch, follow these steps:

Ignite the fuel gases and set the nozzle clearance according to the manufacturer's table.

Heat the material until it reaches ignition temperature.

Start the machine movement and gradually open the cutting oxygen valve so that the molten material does not damage the nozzle.

For thicker plates, use a longer piercing oxygen time to ensure clean penetration without clogging.

Proper piercing technique improves cut quality, prolongs nozzle life, and ensures a stable cutting process—especially when working with demanding materials and thicker steel plates.