Mark the center of each piece of elastic like so. Place elastic on top of fabric, lining up the markings and pin. You will see the elastic sits just shy of the raw edge of fabric the whole way down and that’s what we want.
Pin the layers together along the length, with the raw edge of fabric to the right (so that you’ve got something to hold onto on the left as you sew). Position your needle over the line you marked on the elastic, which if pinned correctly will sit 2/8″ in from the raw edge of swim fabric.
Using a stretch stitch (or narrow zig zag), sew elastic to fabric with a 2/8″ seam. So far so good.
To pull strap out the right way, attach a safety pin to the end, catching elastic and fabric.
Now here is the fun bit. Go on, thread that elastic back through the fabric and admire the work of art that is your beautiful, flat swimsuit strap…
To finish of the ends of the straps, fold them under approx 1/2 ” and secure with pins. Sew in place, ferociously, back and forth several times.. This is my bodgy bit, the straps kept getting caught on the feed dogs and moving around so props to you if you’ve got your stitching looking all pretty on this part. Cut off any excess fabric/ elastic. If you are bi-passing the detachable part, your straps are now read to sew on…
To attach our ‘g-hooks’, thread straps through the hole then back over onto themselves, pin in place, making sure you have a pair of opposites. Sew back and forth again across where you’ve pinned.
The next step is to making the teensy tiny loops that fix to the body of your swimsuit, where the g-hooks attach. Cut a strip of fabric roughly 3″ x 1 1/4″. Fold in half length ways, right sides together and pin.
Cut tube in half and abandon baby tubes for the moment. So, to make that little loop on the swimsuit where the g-hook will slide into, one end of these baby tubes will be attached right after attaching elastic to the top of the Bombshell (or other suit) but before the part where you fold that top edge down over the elastic and zig-zag the entire rim. On the Bombshell suit there are markings where the straps go (marked here with a pin) but it’s a good idea to try your suit on at this point, pinning your new straps to make sure you’re happy with the same placement.