Symmetrical welding

Never weld a long seam straight from one end to the other. The metal expands when heated and contracts when cooling – this distorts the part if you only weld one side. So weld in short sections and keep alternating sides so the shrinkage forces cancel each other out. On thick parts you have to keep the heat in check, otherwise you build up internal stresses that later cause cracks. If you clamp the part well and plan the welding sequence carefully, everything stays straight and low-stress.