It can be difficult to find a bikini bottom that fits you just right. If you sew one yourself you can make a custom bikini bottom. You can pair it with a top you already own or just wear it by itself. Swimsuit fabric can be a little tricky to work with because of the stretch and slippery nature of the fabric. However, if you give it a try the benefits can be well worth the effort.
Cut the panties open along the side seams with the scissors. Fold the panties in half lengthwise.
Fold the swimsuit fabric in half lengthwise with the right sides facing each other. Place the panties on the swimsuit fabric, lining up the fold of the panties to the fold of the fabric.
Trace around the panties 1/4 inch from the edges with the chalk. Remove the panties. Repeat the tracing with the lining fabric.
Cut out the swimsuit and the lining along the lines with the scissors.
Measure around one of the leg holes of the swimsuit with the measuring tape. Cut two pieces of elastic, each the length of this measurement minus 1/2 inch.
Measure across the top front of the swimsuit and cut a piece of elastic the same length minus 1/4 inch.
Measure across the top back of the swimsuit and cut a piece of elastic the same length minus 1/4 inch.
Lay the lining on the bikini bottom, with wrong sides together. Place the elastic across the top front edge, lining up the edges of the bikini, lining and elastic. Pin the three layers together, stretching the elastic as you pin. Repeat to the top back of the bikini.
Serge across the top front edge of the bikini on the serger, attaching the elastic and lining to the bikini. Repeat to the top back edge of the bikini.
Pin one of the pieces of elastic to one of the leg holes starting at the front of the bikini. Stretch the elastic after the crotch once you reach the part that covers the butt. This helps keep the suit in place. Repeat to the other leg hole.
Serge the leg holes attaching the elastic and lining to the bikini.
Fold the bikini at the crotch, right sides facing each other, so the two sides of the front and back meet.
Serge the side together.
Fold the top of the bikini down 1/4 inch over the elastic. Sew the top in place with a stretch or zigzag stitch on the sewing machine with the ballpoint needle.
Fold the leg holes in 1/4 inch over the elastic. Sew the folds in place with a stretch stitch zigzag stitch on the sewing machine.