Easy Swimwear Fabric Sewing Tips

If you’re frustrated with swimsuit shopping, then it’s time to make your own! I love sewing and teaching swimwear and I have easy tips to help you successfully dive into sewing your own suit. Best of all, Coats and Clark has a marvelous new thread, Eloflex, to make your swimsuit sewing dreams come true!

What is Swimwear Fabric?

Swimwear is a unique, ultra-stretchy, knit fabric that is really quite easy to work with once you know a few tricks and tips! Look for a Nylon/Spandex blend fabric with two to four way stretch. In general, you’ll want a fabric with 50% stretch one direction and 75% stretch the other, but do check what your pattern requires. The greatest amount of stretch will go around your body, so keep that in mind if you’re choosing a print, plaid or stripe.

You won’t need to pre-wash your swimwear fabric, but your finished suit can be hand or machine washed. It should never be put in the dryer and you’ll want to stay away from bleach or harsh detergents. They will damage and shorten the life of the fabric in your finished suit and you don’t want that!

Checking the Percentage of Stretch

To accurately check the percentage of stretch on the fabric you’ve chosen, you will need to use more than the 5” shown on the back of most knit pattern covers. Instead, learn and use this reliable method.

  • Create a 10” fold straight across the width of your fabric, at least 10” up from the cut end and 10″ away from the selvage.
  • Hold the beginning of your fold securely at the end of a yardstick or ruler and stretch the other end gently, yet firmly beyond the 10” mark.
  • If the 10″ fold of fabric stretches to 12.5”, you have 25% stretch. If it stretches to 15”, it has 50% stretch, to 17.5”, it has 75% stretch and to 20”, it has 100% stretch.
  • Repeat this for the length of your fabric, too.

Choosing Threads and Needles

Eloflex is INCREDIBLE and an amazing leap forward in the world of sewing knit fabrics. I just can’t stop gushing about it! Eloflex allows your straight sewing machine stitches to stretch and spring back easily once your seam is sewn. No more snapping stitches! For your sewing machine, select a coordinating color of Coats Eloflex stretch thread for the upper thread and bobbin and purchase two spools. Swimsuits involve a lot of top stitching, elastic stitching and, if you’re sewing seams on your sewing machine, double stitching, too.

Coats All Purpose Surelock Thread

If you’re using a serger for the seams of your swimsuit or for the elastic, purchase four spools of Coats Surelock Thread.

Use size 70 or 75 Stretch or Ballpoint needles for both your sewing machine and serger. For the best results, start with brand new needles. If you can’t find Stretch or Ballpoint, Universal is next best.

Sewing Machine & Serger Stitching

The wonderful stretch and fabulous recovery of Eloflex Thread allows you to easily use a straight stitch on your sewing machine for your swimsuit seams. If you’re using a serger, set it for a four thread overlock stitch. Use a slightly longer than normal straight stitch on your machine and serger – about 3.5mm. To find the best stitch and tension combination for your sewing machine or serger, start by creating samples with a swatch of your swimwear fabric and elastic. Try several different lengths, settings and tensions, then save your final sample and make notes on your preferences.

To reduce bulk, finished seams on your swimsuit should be 1/4″,  but you may find that your pattern was created with a 3/8” or wider seam allowance. On your serger, set your stitch width at 1/4” so that the knife will trim your finished, overcast seam. On a sewing machine, you’ll carefully trim your seams to 1/4” once you have double stitched with Eloflex thread.

Elastic Stitching

On a sewing machine, you’ll use a zigzag stitch to attach the edge of your elastic to the swimsuit openings. Once the elastic is attached and turned to the inside, you have several choices for your second stitching, using your Eloflex thread.

A double needle stitched from the right side creates a nice, professional finish, but a zigzag or serpentine stitch works equally well for your second stitching. If you’re using a serger or coverstitch machine for your elastic, your manual is your best friend and will tell you just what you need to know!

Modified version of Kwik Sew 3609

And, there you go! You can have the suit of your dreams, designed and made by you. Choose a pattern, keep these hints nearby and enjoy dipping your toes into the exciting world of sewing with swimwear fabric and Eloflex Thread!

2 thoughts on “Easy Swimwear Fabric Sewing Tips

  1. Charlotte Trayer Reply

    So glad to see a really reliable method for checking the stretch of knit fabrics (it works for all of them)! It’s how I learned to do it almost 50 years ago when I took my first sewing on knits class!!

    • Annette Millard Post authorReply

      Thanks, Charlotte! I’ve always been pleased with the results of this method, too.

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