1F Description: The weld is made on the upper side of the joint, with the weld face approximately horizontal.
The is considered the easiest and most common fillet weld.
4F Description: The weld is made on the underside of the joint.
Jack smiled. "Easy fix! Just re-weld the joint in the correct orientation. And remember, when welding in the horizontal position, always deposit the filler metal in a downward direction."
Here is a breakdown of each position, its challenges, and how to succeed.