Cleanliness is a major factor which can have a significant effect on weld quality, both from the
psychological point of view and also from the potential risk of contaminating the weld. Obviously, every
attempt should be made to produce a clean working environment in the general area, but in the actual
welding area the requirements for cleanliness must be mandatory. Welding should not start if the weld joint
is contaminated or likely to be contaminated with potentially harmful extraneous material. Oil or grease
must be removed thoroughly and any potential source of grease eliminated. Repair of mechanical
components often leads to grease in bearings or crevices melting and running into the weld area as the work
piece is heated by the welding in progress.