What is a self-welt pocket
A self-welt pocket is a slash pocket style that looks identical to a single welt pocket application. However, there is a major difference in the construction process: A self-welt pocket uses a single fabric layer to form both the welt-like pocket opening and the entire pocket bag.
All you need to construct a self-welt pocket application is an extra long pocket piece. In this case the pocket opening is 1" by 4" thus the pocket piece measures 5" x 10" to include 1/2" seam allowance along all edges as shown above.
The pocket layer is used to clean finish the pocket opening edges after which its bottom portion is folded up to cover the pocket opening and create the welt-like fold.
The pocket piece is then folded onto itself to complete the pocket bag.
In the finished application, the pocket opening welt is naturally exactly the same fabric as the pocket bag.