One of the most important techniques of creating a great weld is done even before the weld is started. This imperative step is prepping the surface correctly. Weld preparation can be the difference between a great weld and a weld that is just sufficient. Sure you can begin welding without any preparation over rusted or paint covered steel and you will complete the job, but if you do not want to compromise for mediocre results it is imperative to correctly prepare the pipe welding machine surfaces before starting on the weld. If you do not do this it will suffer visually and structurally.Welding surface prep is a pretty straight forward process. It is typically done by prepping the surface with an angle grinder. The greatest attachment to utilize for this is a coarse grit flap disc. A flap disc is good as it will only remove the mill scale or corrosion and not gauge into the material like a grinding wheel would, possibly compromising the structure of the steel. To remove corrosion you will want to attach a cup wire wheel to an angle grinder and run that along the surface of the steel. To remove paints or heavy rust you should prep the surface by grinding it at the beginning with a grinding wheel to get rid of most of the corrosion and then use a fine or other grit flap disc with the angle grinder to finish out the surface.Another benefit of grinding the surfaces of the steel is so you can be sure that the ground makes sufficient contact with the metal. Keep in mind that any paint or rust will inhibit the flow of the current from the ground to the metal. This will result in a weld that may look robust cosmetically but will be very weak structurally because the weld did not penetrate the surface correctly. So it is imperative to not only prep the surface where the weld will be but also where the ground contacts with the surface.
