Foundation paper piecing helps you to construct otherwise complicated blocks with pin-point accuracy.
With foundation paper piecing, you place the fabric on the (back) blank side of the foundation (the paper pattern) and sew on the (front) printed side of the pattern. The foundation is numbered; you will sew fabric pieces in number order until you’ve sewn all the pieces in the pattern, then you’ll trim the sewn foundation leaving an exact 1/4-inch on every side.
Some quilt blocks are pieced in sections; in that case, you foundation piece the first section and trim, then foundation piece the next section and trim, and so on. Once all sections are pieced, you sew them together.
1. Place the first fabric (A1) right side up on the back (the unprinted side) of the foundation
Pin the fabric in place from the front (the printed side) of the foundation.
Hold the foundation up to the light and check that the fabric covers the A1 space, leaving a generous 1/4-inch seam allowance over the line between the A1 space and the A2 space. Check that the fabric also leaves a generous 1/4-inch seam allowance along the other sides of the A1 space.
2. Place a piece of cardstock on the line between the A1 and A2 spaces
Flip over to the front (printed) side of the foundation, and place a small piece of cardstock on the sewing line between the A1 space and the A2 space. Notice that the cardstock is covering the A1 space, its edge facing the A2 space.
3. Use an Add-A-Quarter™ ruler to trim the fabric
Fold the foundation backwards, over the cardstock. Butt an Add-A-Quarter™ ruler up to the cardstock edge, and trim the excess fabric to an exact 1/4-inch.
4. Align the next fabric with the cut edge of the first
Flip over to the back (unprinted side) of the foundation. Place the second fabric (the A2 fabric) on top of the first fabric, RST. Align the edge of the A2 fabric with the freshly trimmed edge of the A1 fabric. Pin.
5. Change to a Jeans 90/14 needle
A Jeans needle can pierce the paper more readily than other needles, so it’s recommended.
6. Sew on the line between the A1 and A2 spaces
Flip over to the front (printed side) of the foundation and sew on the line between the A1 and A2 spaces using a short stitch length. Start and end your stitching just before and after each end of the line. Stitching with a short stitch length helps you remove the foundation papers later when everything is sewn together.
7. Unpin the fabrics and press open using a dry iron
8. Place cardstock on the line between the A2 and A3 spaces
Flip over to the front (printed side) of the foundation. Place the cardstock on the line between the A2 space and the A3 space.
9. Fold the foundation over the cardstock, and use an Add-A-Quarter™ ruler to trim the excess fabric to an exact 1/4-inch
10. Place the next fabric on top of the first
Flip over to the back (unprinted side) of the foundation. Place the next fabric (the A3 fabric) on top of the newly-trimmed fabric, RST. Align the edge of the next fabric with the freshly trimmed edge of the other fabric. Repeat Steps 6-10 to add each fabric piece in order.
11. Trim the outer edge of the block or block section
After sewing all the fabric pieces to the foundation, trim the outer edge making sure to include an exact 1/4-inch seam allowance. The solid line on the foundation marks the block’s or section’s outer edge. Measure 1/4-inch from this solid line.
12. Do not remove all of the foundations just yet
You can remove the middles pieces of a foundation as you construct a block, but you should keep the foundation pieces in the seam areas until you’ve sewn those seams together. That way, you can remove foundation pieces you don’t need as you go along, and use the foundations left in the seams to help you align blocks and block sections properly for sewing.