07 Jun 2013 • • by Heather Lou

Bombshell Sewalong Pt 1 - Material Requirements

Sophie // Fabric and Supplies

Today I want to discuss the material requirements of the Bombshell Swimsuit, an important first step before you dive into making it!


Many vintage style swimsuits use non-stretch fabric. The Bombshell is NOT one of them. You really need a lycra fabric that can survive the stresses of salt, sun and chlorine. This suit fits like a second skin and you want a fabric that has enough stretch to get on and off, and will hold its shape when wet.

I am calling it “swimwear lycra” but this material is also used to make skating and gymnastics costumes as well. What you want is a fabric blend of spandex and nylon (called lycra even though I believe this is a brand name of spandex, much the way we call tissues “Kleenex”). The ideal ratio is 80-90% nylon and 10-20% spandex. The nylon gives the durability and the spandex provides the stretch. This is the only material I can safely recommend for this particular suit. Unfortunately, natural materials like cotton or rayon knits are not going to work here.

As for the lining, you want a stretchy knit lining fabric, again in synthetic fibers like nylon or polyester. I used a nude lining in all of my samples but you can also get a black lining for darker suits. Anyone interested in making a white bombshell should take a look at the HOLY OMG AMAZING miracle that is Carolyn’s make. She lined hers with the same fabric she used on the outside. If you were still feeling nervous about nip slippage, you could do an extra lining at the crotch and bust in nude, just to be one the safe side.

A few of my pattern testers lined their fabric in the same material they used on the outside – this is totally a viable option but just keep in mind that the fabric is definitely thicker than the lining and you are adding a little bulk/weight to your suit, especially when it gets wet. But from what I’ve seen, it does not affect the way it looks on whatsoever.

Where to Source Swim Fabric

Before heading anywhere else, I suggest heading over to our sister store Core Fabrics. We carry a wide range of sustainable recycled nylon swimsuit fabric, deadstock printed swim fabrics, linings, and swim notions like rubber elastic. You can see everything you need for the Bombshell here. Otherwise you may want to check out:

Elastic for Swimsuits

The type of elastic you chose to make your suit will have a huge impact on its lifespan. Traditional polyester elastic is not the best choice for swimwear. It breaks down in salt and chlorine and will ultimately not stand the test of time. There are two options for swimwear elastic.

Rubber elastic

Rubber elastic comes in white or black. The black rubber I used for all of my suits so far has slight ridges on it which make it easier to line up with your fabric edge when sewing it down.

Swimwear elastic

It is also known as “natural” or “cotton” elastic. It is generally made from mostly cotton and about a third of neoprene. I will be using this elastic for the first time during the sewalong, but I believe this is the more common elastic used in swimwear.

I specify 1/4" elastic but I believe the "swimwear" cotton elastic is mostly if not only, available in 3/8". If you use 3/8" you will be fine. You can get high quality rubber elastic from Core Fabrics here.


Pretty simple. You want a high quality 100% polyester thread. I prefer Gutterman’s but whatever floats your boat. You will go through a lot of it, especially with your gathers and topstitching, so I would suggest getting at least 250 yds.

For those with sergers, I know that using wooly nylon thread in your loopers really helps with the stretchiness of your seams, but I haven’t tried it yet. I may give it a whirl for the Sewalong suit.


Anyone who has sewn stretchy knits on a traditional sewing machine has probably experienced the rage of skipped stitches. Last year when I first started sewing swimsuits I almost threw my machine out the window. Nothing was working.

You really, really need the right needle for this project. You want a needle with a ballpoint so it goes in between the weave of your fabric and catches the bobbin thread. Sharps are likely to give you a world of headaches. I tried “knit” needles but the only kind that guarantees me a nice even stitch are “Stretch” needles. Elona on a Pattern Review board says it best: “The [stretch needle] has a deeper ‘scarf’, an indentation that allows a longer thread loop to form, increasing the chance that it will be caught by the hook of the sewing machine, and that a stitch will be formed successfully on a difficult, stretchy fabric.”

Thanks Elona. Couldn’t have said it better. Now go get some stretch needles.


You can absolutely make the Bombshell sans serger but your machine must have a zig zag function. My first swimsuit was done using just the zig zag on my old Singer. Obviously, the guts of your suit will look a little less polished, but it can be done. I will provide help on how to do this as cleanly as possible.


If you need some support for your big naturals (thank you Sarah Silverman for the best way to describe tatas ever) you should probably pick up some cups. Now, I am a 34D and am TOTALLY fine without support in this suit. The halter version is especially supportive on its own. However, if you want additional boob cradling or even just nip padding, cups are a good idea. I will be doing a post on how to add them to the two views. You can get these cups at any decent sewing supplies shop or wherever you are getting your elastic.

However, since I have not used these yet, I am going to cede some territory to Dixie DIY who did a great swimsuit sewalong last year. Here is what she has to say about cups:

My faves are these kind that I bought at Sew Sassy but I've also seen them on Etsy and other sites. They're soft and flexible and provide more coverage and gentle shaping than "lift." They come in several sizes.If your bust is on the larger side you can combine these cups with a shelf bra in the lining (elastic support under the bust with more room for the "ladies") or you can use a bra-style suit or bikini top and use pre-moulded cups or Poly Laminated Foam as an interlining.

Poly Laminated Foam is often used in swim bras and sometimes regular bras. It is usually a 1/8" to 1/4" thick dense but flexible foam with a soft fabric layer on either side. In normal bras the tricot or power knit fabric provides minimal stretch while still supporting the cups. Although the design may be the same, in swimwear the fabric is way too stretchy to hold in the mounds (know what I'm sayin'?) so the foam gives structure and support without much bulk. You can cut the foam to fit your needs and make your own cups if you want.

Thanks Dixie! You can read her awesome materials post here.


  • Scissors or a rotary cutter and mat (I’m a rotary cutter girl myself. SO MUCH FASTER!)
  • Pins
  • Measuring tape
  • A ruler if you need to make modifications
  • A marking tool

That should do it for supplies! I suggest getting everything by next Monday so you can follow along. I am really excited to get people on the Bombshell bandwagon!


A strange full-circle feeling came over me this morning when I read Casey’s post on yesterday's passing of Esther Williams… She embodied 1940’s and 50's swimsuit glamour like no other. She was a definite inspiration when I drafted this suit and the coincidence of her death and the release of this suit feels weirdly symbolic. Hope there are pools in heaven, Esther.

(Someone quick - do a metallic lame version!)

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