Weld Joint Preparation

Before welding, you have to clean the weld prep edges – remove rust, paint, oil, and dirt. Otherwise you'll get porosity or the weld won't bond properly. Grinding or brushing is usually enough, but make sure no grinding residue stays in the joint. If the material is cold or damp, you can preheat it slightly so the weld runs clean. But don't overdo it, or you'll ruin the structure.