Kwik Sew 3875 bikini sew-a-long & tips for sewing lycra / Spandex #MMMay18

Ah, the difference a week makes. It was sunny, I didn’t have an eczema flare-up and the pool was warming up nicely. So, it seemed the perfect timing to tackle the bikini sewing project that I’ve guilty had sitting in my to-do-pile for…..about 4 years. Yup, 4 years.

Back then, it was harder to get lycra swimsuit fabric in the UK, especially with spandangerly digital prints, so I ordered a whole bunch over from the US to make the most of the postage.

Sewing my first bikini was smooth sailing (watery puns here we go) and dipping my, back then, novice toes into stretch fabrics wasn’t as scary as I suspected it might be.

Saying that, lycra and Spandex does have its own challenges and there are a few tricks worth having up your sleeve! Here’s some of the things I’ve learned…

Tips for sewing lycra / swimsuit fabrics

  • Use the appropriate needle – You can’t do without a stretch, or even better, super stretch needle
  • Attach a walking foot – This helps feed the fabric through evenly, mitigating a wibberly edge and helping prevent the machine chewing up the fabric (pics on this below)
  • Use nylon or polyester thread – These are more resilient to the stresses of chlorine and salt so will help your creation live longer (wind nylon thread onto your bobbin slowly…it can take on a life of its own!)
  • Use a tail – This is where you start sewing on a more stable woven fabric then feed in your lycra / Spandex. It helps prevent the machine chewing up  the fabric during those those crucial first stitches (see pics below)
  • Use a zigzag – If using a regular machine, rather than an overlocker / serger and do test runs on scrap first to test the stretch for the right size of zigzag (some machines have a stretch stitch, but I found this to use an excessive amount of thread and to be almost impossible to unpick)
  • Check your grain line – Yes, lycra can have a more dominant stretch in a certain direction and this can affect your project especially for things like straps
  • Bonus – See a hack for turning bikini straps below using wire!

A mid-range upwards machine will also help, as while sewing my first bikini on my low-mid end Janome was a breeze, the starter machine I bought from Singer (for travels) struggled big time to handle this trickier fabric – I had to pull out all the tricks in the book to make this happen!

Saying that, most of my sewing sins were dealt with or are hiding away from public eyes, and I’m really pleased with how the project turned out. Most of all, I am head over heels for the garden digital print lycra I got from Funki Fabrics.

For the pattern, I used Quik Sew 3875, a simple triangle bikini with tie side briefs, and very clear instructions / diagrams. This time, I made a few minor modifications:

  • One chest tie instead of two: I felt the double chest strap was unnecessary, so simply sewed one channel on the cups and one chest string
  • Lengthened the straps: I lengthened all straps by a few inches as I prefer a little more to dangle, and for the double ties at the neck it makes it easier to tie
  • Sized up on the cups: For a little more coverage / gathers!

You can easily get this done within a day, although I spread it out over a few, and it’s a very satisfying make.

I’ve got an idea for a self-designed fabric for the next one….and would like to attempt a reversible version. Glutton for punishment or inspired, it’s your judgement!

As usual, here’s a few awkward selfies and sew-a-long pics after the jump.



Kwik Sew (3875) bikini sew-a-long 

  1. The pattern is fairly simple, and you could draft it from an existing triangle bikini and good coverage pants. Don’t forget you’ll need lining fabric and swimwear elastic. I’ve used two kinds: A thin transparent elastic and a thicker more rubbery white swimwear elastic…I have to say, I preferred the white kind as it seemed to stay in place better when stitching whereas the transparent stuff was somewhat flimsy and harder to manipulate.


2. Here, I’ve stitched the lining to the cups leaving gaps to turn them right side out at the tops and also for the chest strap channels at the bottom.

As I mentioned, I’ve only stitched one channel for the chest straps (about a centimetre in) – You’ll notice I’ve used a very narrow zigzag here. I’ve then turned the tops over to make loops, stitching multiple rows to avoid any embarrassing breakages when wearing!

See the cup on the right has a slightly wavy bottom seam? This is because I didn’t use a walking foot, and started using the walking foot for the cup on the left – what a difference it makes! The left cup has a perfect seam and was much easier to sew!



3. Here, I’ve attached the two bottoms pieces along with the lining.



4. Then, I flipped the lining, joining it around the legs to the front piece.


5. The elastic is zigzagged on around the top, bottom and leg holes on both pieces of the bikini bottoms. Here I used a ‘tail’ when starting my lines of stitching – this means I started stitching on a more stable woven fabric for a few cm, feeding in my lycra. It helps stop the machine chewing those crucial first stitches (you can see where this happened on the opposite row, below).

Note, tissue paper is pictured as my ‘tail’ here, but I found a thick cotton from my scrap basket much more effective.


6. Once I zigzagged the elastic on, I flipped the seam over (covering the elastic) and zigzagged along the edge to secure it (effectively, hiding the elastic). Then, simply turned in the sides to make loops for the straps (as with the bikini top).

Onto the straps! Easy…just long lines of stitching then turning right side out. To turn the straps, I didn’t have a safety pin or hair grip, so I came up with an ingenious homemade strap turner using wire! This worked excellently!


7. Time to thread the chest, bottom and shoulder straps in!


8. And, done! Time for coffee and a swim!


Here’s our favourite spot for peak sunshine swimming – Pond Du Loup, stunning natural pools and waterfalls, tucked away in the foothills of the alps on the Cote d’Azur and well beloved by locals! It makes for a refreshing dip for scorching days – here’s us with my sister earlier this year when the waters were icy cold but the sun was shining!


What is Me Made May?

I hear you, my non-sewing friends…what the hell is this Made May thing about….

This my first year and I’ve been wanting to take part for so loooong, but not had the time until recently with my travels to France.

Essentially it’s a whole month dedicated to sharing and wearing what you’ve made, whether by sewing, crochet, knitting, weaving…you name it. More detail here.

It’s inspiring to see what other’s have created, and I love celebrating the maker culture and being given a focus for my dressmaking among like-minds.

Check out the hashtag #MMMay18 to swoon over the latest makes.


4 thoughts on “Kwik Sew 3875 bikini sew-a-long & tips for sewing lycra / Spandex #MMMay18

  1. Ooh I love love love this print!! Might have to add this to my wish list. And what a great tip using a “tail”, I’ve never seen that before, will be definitely using it for other projects (I’ve had a few silk tops gobbled up by my machine in the first stitches!!) Thanks!!

    Liked by 1 person

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