A
welder or
welder operator is a tradesperson who specializes in
welding materials together. The term welder refers to the operator, the machine is referred to as the
welding power supply. The materials to be joined can be
metals (such as
steel,
aluminum,
brass,
stainless steel etc.) or varieties of
plastic or
polymer. Welders typically have to have good
dexterity and attention to detail, as well as some technical knowledge about the materials being joined and best practices in the field.