Plasma Cutting - Watch the Dross

On the underside of any plasma cut, small amounts of slag may collect along the sides of the cut. This dross can be significant or minimal. It can be hard to remove, or easy to remove. If it is significant, and hard to remove, and you notice that the cut line angle dramatically increases toward the rear of the weld, it is a good sign that the maximum cut capacity of the plasma cutter is near or the maximum cut for the set amperage has been achieved. If it is significant and hard to remove, but cut lines are normal, air pressure may be low. If the dross is significant and hard to remove, and the cut lines are irregular, then cut speed may be too fast. If dross is irregular, then cut speed may be varying, or torch height may be changing. If needed use a cut guide, or a standoff to keep a consistent cut height. Be careful also to watch for discoloring of the cut or sootiness, of the consumable, if any negative cut condition occurs. This may be an indication of moisture in the lines. Ideally, the cut should have less than 1/8” of dross on the cut backside, and cut lines are angled at a 30-40 degree angle toward the rear of the cut if all things are working as they should. Melting back over of the dross or closing up of the cut can indicate too slow of movement, or too low of air pressure or too high of amperage for the thickness. Loss of cut can indicate too fast of travel speeds as well.