Clean all weld surfaces of loose slag, rust, oil and foreign matter. Make sure the weld surfaces are smooth and uniform.
Align the piping in the proper configuration. Secure the two pipes together with a clamp.
Use your welding tool to create small welds of a uniform size, spaced at even intervals, around the pipe joint. The small welds, called tack welds, will hold your pipes in place when you make the main weld to hold the joint in place.
Weld around the entire circumference of the joint. Use a curved, zigzag motion when welding metal less than 2 mm in diameter. Use a straight weld when welding thicker metal.