In welding, there is no one size fits all rule as to rod size and current. A number of factors determine the specifics for a welding project. Because there are many rod sizes made of a number of different materials; the electrical current needed is based on a number of factors such as the degree of arc, size of flame, degree of heat needed and so forth.
Welding is a very dangerous activity requiring specific precautions to prevent, burns, poisonous fumes, overexposure to ultra violet light and electrical shock.
Welding is a process of fabrication, used to join materials together such as different tuypes of metal, but also some thermoplastics are used in welding.
Normally, in welding you have a diagram of the project and the specifications, clearly state: metals, rod sizes, electrical current required, the heat source and so forth. Even very experienced welders use this type information.
