MAGNA

Just as there is no universal medicine that will cure all ailments, some cast iron repairs lend themselves to gas welding better than arc welding. In other cases, arc welding is more practical than gas welding.

Types of applications where oxyacetylene welding is generally preferred:

• Small parts, such as a broken lever.
• Repairs such as a fracture where both parts to be joined are loose and free to move.
• Welds where the weld metal must have the exact, or almost exact, same properties as the base material. For example, a glass mold where a weld with dissimilar coefficient of expansion and contraction could cause a spot or flaw in the glass.
• In some machine applications where heat, corrosion, color or other reasons require that the weld metal have the same properties as the base metal. For example, valve ports in cylinder heads.

Most engineers would prefer to oxyacetylene weld any part where facilities are available and it is practical to preheat, especially on parts where the crack cannot be reached by an electrode but the iron must be melted in order to obtain access. For example a crack between valve ports. Here usually only the top of the crack is reachable. It is therefore necessary to melt down into the crack in order to weld the complete crack. In such case, the oxyacetylene torch is naturally used.