How to Level a Square Butt Weld 90

Position the two work pieces that you are going to weld together on a heat-safe workspace at a 90-degree angle. Move them 1/16 inch apart if they are thinner than .04 inch in width. The space between the two edges that you are going to weld together, or the weld joint, will allow you to make a level, even butt weld.

Place the current setting of the arc welder to 80 amps. Put on your welding apron, face shield and heat-resistant gloves. Touch the metal with the electrode to start the spark or welding arc.

Begin welding the 90-degree butt weld joint at the top of the joint, moving the electrode in a slow pattern of overlapping triangles. Weld part way down the joint and move the electrode to the bottom of the joint. Weld in the same overlapping triangle pattern up part way -- the weld puddle should move and fill in the center of the joint due to capillary action.

Wait for the metal to cool. Use an electric metal grinder to remove any slag -- small bits of blackened metal that formed during welding -- and to make the corner smooth and flat so that it is level with the surface of the two pieces you welded together.