The general repair or implementation of engineering changes on larger molds and dies by welding is accomplished very often by standard GTAW or TIG welding.  Surprisingly small weld metal deposits can be applied, even without the use of microscopes, when appropriate care, skill and equipment are used.  Very heavy or larger sized build-ups are accomplished by patiently welding layer on layer on layer of filler rod until the required dimensions are reached.  Although more time consuming, applying multiple thinner layers is preferred as this helps prevent the formation of voids in the weld.

Special cases may require the use of GMAW (MIG) or SMAW (Stick) processes, especially when applying many hardfacing or wear and chemical resistant filler materials.