OK, run your finger along what is your inside fabric seam to kinda of backward finger press that seam open. Pin your seams and sew 1/4" seams.
Since your seam allowance is cut at 1/8", you essentially are encasing it within the 1/4" seam you are now sewing. Be sure to back stitch a few stitches at the beginning and ending of this seam.
Last edited by SewExtremeSeams; 12-02-2013 at 08:31 AM.