sewing a slip cover and forming square corners

A 6 piece , pattern
to cover a rectangle piece of foam for a seat.
My question is when joining the bottom and top how do you
sew the corners to make them square?

One Response to “sewing a slip cover and forming square corners”

  1. Judith says:

    After seaming the corner fold the seam allowance over on the stitching line and press. You will notice bulk at the corner that you can trim and grade then turn the cover right side out and press again. The foam may not be strong enough to keep the corner square so don’t be discouraged.