In oxy-acetylene welding of cast iron, the metal is first cleaned and preheated slowly to avoid cracking. A neutral flame is used, and a cast iron filler rod with flux is added to join the broken parts. After welding, the workpiece is cooled slowly.
For aluminium welding, the surface oxide is cleaned before welding. A neutral or slightly reducing flame is used together with aluminium filler rod and flux. The welder heats the joint carefully because aluminium melts quickly.
In stainless steel welding, the metal surface is cleaned properly to remove dirt and grease. A neutral flame is used with stainless steel filler rod and flux if needed. The heat is controlled carefully to prevent distortion and maintain corrosion resistance.