Five Quick Swimwear Sewing Tips

At Ellesby Fabrics, we sell a lot of swimwear spandex. It's probably our biggest seller. So if you found this post on our site, I'm going to presume that you have some of the basics down about sewing stretchy fabrics.

However, if you are ready to take your swimsuit to the next level, read on. Whether you sew for fun but want to build a bikini to last, or you've committed yourself to selling bathing suits by seashore, it's good to know how to go from good to great with your sewing.

Get your pieces looking store-bought with these five tips that you might not know.

Tip 1: Line of Sight

Fully lining your beachwear can be an easy way to say that you're a pro.

Generally, all you need to do is cut the original pattern out in the lining and sew the lining in as part of the garment construction. Unlike skirts and dresses, swimwear lining is fully encased and attached to the clothing, with the only slight exception being a shelf bra that will have the lower band separate from the outer fabric.

Lining fabric is generally much less expensive than swimwear fabric. I recommend Helenca, pictured inside the bikini bottom at the right, as a very comfortable and inexpensive professional option. It is 100% nylon with mechanical stretch. The downsides are that it does snag easily, and the lack of spandex in the contents keeps it from excessive stretching.

Power net and compression materials can be good for lifting, slimming, or holding in parts of the body while also acting as a lining.

For really a high-end pro look, think about what signature color you want your lining to be. Tan, white, black, pink? Spandex is normally pretty opaque, so you can have fun with your lining being a standout shade.

Need lining fabric? Check out what we have in stock here.

Tip 2: Smooth Things Out

My mother taught me that the best sewists are the best pressers. But do you need to take your iron out for swimwear? No way! It would damage the fabric, even on low heat.

Instead what you want to do to smooth out those seams and hemlines is to do a form of intensive finger pressing. I use the edge of my sewing table and rub the material in the normal press sequence (link). You can see how that looks with the green stretch stitched thread in Helenca swimwear lining for an actual swimsuit in this video.

Tip 3: Serge Ahead

Got a serger? Why not use it to finish your swimwear edges? Sure, spandex doesn't fray and can last for years without overlocking your edges, but it makes it look right out of the store when you do. If your serger doesn't have a coverstitch capability (generally, machines that handle 5 or more threads can do a coverstitch), don't fret! Coverstitching holds up to stretching for a little while, but frequent use of swimwear causes a normal coverstitch to break. Serging your edges with a three-thread overlock and doing a machine zigzag topstitch withstands stretching better.

Whether you are using a coverstitch or just borrowing a three-thread overlock machine from a friend, here are a few ways to make your swimwear serging surge:

If you are thinking about overlocking with a topstitch, it looks best to match your serger thread to your topstitch thread.
Sewing a lot? Considering matching the interior thread to your lining color so that you don't have to rethread your serger often.
Want to create a high-end look for your small label? Glam up your swimwear with a purposeful contrast color of serging that will be consistent across your brand. Maybe try red thread that will pop whenever someone inspects the interior of their swimsuit.

Tip 4: Evening Stretches

Inserting elastic is almost always part of making swimwear.

In general, the rule is that the length of elastic should be about 75% of the length of the unstretched fabric plus about 5-15% for elastic seam allowance and extra comfort. This results in about 80-85% the length of the unstretched fabric as the length that my elastic will be. I normally add:

5-10% for leg holes (about an inch)
10% for women's lower torso bands (chest, undercup, waist)
15% for men's waistbands and women's upper torso to avoid discomfort

Now that you know the length to cut your elastic even if you don't have a pattern to follow, what is the best way to insert it without creating uneven tension?

When sewing in elastic, I usually do a quick straight stitch to secure the ends to the fabric. Then I divide the fabric and the elastic in half. The elastic will be a lot shorter, but now I know where the middle is. I sew that down with a straight stitch just to secure it. I keep find halfway points between the areas that I have sewn down sections no longer than about 9 inches (20 cm). Sewing it holds the elastic in place better than pins for final sewing. The elastic is fully sewn with a lingerie stitch or zigzag favoring the side of the elastic not aligned with the edge of the fabric.

Tip 5: Finishing Strong

Often, the little things make a big difference. Think about times when a glint of gold or a whimsical detail made you want to buy something over the item you were looking at?

First, if you are selling your swimwear, most countries require origin and contents tags on the clothing. This is a great opportunity to optimally set your items apart. If you're not sure how to go about getting tags, check out my article on tagging for small-scale makers.

But your clothing will also stand out with some really minor additions in the notions department. A little bling or bauble can add a lot of character, so consider some of the following inexpensive ways to make your swimwear snazzy: