Happy Swim Season everyone! It’s Tamar from Tamar Hope Designs, here to chat about sewing with swim knit! I love sewing swimsuits for my kids. There are so many fun options for fabrics and patterns! And my kids love helping me plan out their suits for each summer.
A lot of people are terrified of sewing on swim, but I’m here to tell you that it’s really not all that different from sewing on regular knit. The only difference is that it is slippery. And I’m going to tell you how to deal with the slippery factor.
So, what are you waiting for, pick a pattern and let's dive in! My kids and I are big fans of sleeves, because we really don’t like slathering on the sunscreen. So, Plumeria was the obvious choice for this suit. My daughter, however, prefers a two piece for easy bathroom breaks. (Let’s face it, no one likes to try to pull a wet one piece suit up and down if they don’t have to.) So, after giving you all the swim tips and tricks, I'm going to show you how to make Plumeria a rash guard. Then I will also show you how to modify the Monstera Board shorts to be a stand alone swim bottom for girls! My daughter loves how this suit turned out!
Everything that I said about sewing with knits applies to sewing with swim. Check out the post about sewing with knits if you missed it. Here’s a quick overview of the basics. Use a ballpoint or stretch needle. Use a stretch stitch (like a zigzag with a stitch width of 2 and a stitch length of 2). Optionally, you can use stretch thread in both the needle and the bobbin or wooly nylon in the bobbin. A walking foot can also be very helpful with knits. And use a double needle and a long straight stitch for hems.
With that basic foundation, let’s jump into swim knit!!!!
Cutting
When cutting your fabric, remember that it is slippery and will shift easily. I highly recommend using a rotary cutter, a cutting mat, and some pattern weights. (For pattern weights, I actually use anything that has weight that is within reach - cans, tape dispenser, etc.) I also like to use my straight edge as often as possible. I find that if I am pressing down on my straight edge the fabric never shifts. If there are any straight edges, cut those first with your straight edge. Your fabric will stick slightly to a self healing cutting mat, keeping it from shifting when you cut the other edges.
If you don’t have a cutting mat and rotary cutter, don’t worry, you can still cut out swim fabric. I would recommend tracing your pattern piece on your fabric with a washable marker. Then use sewing scissors to cut on the inside of the marker line.
Sewing
With swim knits, I highly recommend using quilting clips.
They keep the fabric from slipping without putting any holes in the fabric. Use more clips than you think you need. Swim knit will want to slip all over the place and clips will prevent that from happening. As with any knit fabric, use a stretch stitch. I have personally found that the best stitch for strength and stretch is the zigzag stitch with a stitch width of 2 and a stitch length of 2.
Don’t start stitching right at the edge of your fabric otherwise your machine might pull your fabric down through the plate. Instead start ⅛ - ¼ inch from the edge.
Zippers
If you are sewing Plumeria, you will need to install a zipper.
Don’t be afraid of a zipper! I promise, with wash-away wonder tape it’s not scary at all!!! Carefully follow the directions for steps 14-21. At step 22, secure the edge of the swim knit to the edge of the zipper.
Just make sure that you don’t stretch the swim knit at all. If you stretch it while you are taping it to the zipper, your zipper will be wavy when you are done stitching. With the swim knit securely stuck to the zipper tape, sewing it together is simple.
When you get to steps 24-26, it is super helpful to have a teflon zipper foot. They are not very expensive, and they will come in handy anytime you are sewing with a fabric that can be sticky (swim, vinyl, leather). You can also try putting tape on the bottom of your regular zipper foot. I have to admit that I’ve never had great success with that, but I know that some people like that option.
As an example, here is some topstitching done with a regular zipper foot.
The fabric has a tendency to stick and bunch.
On the other hand, the teflon zipper foot slides across the fabric, making the topstitching a breeze.
Elastic
First of all, I would recommend getting swim elastic. Swim elastic will hold up better in chlorine and salt water than regular elastic. Before cutting your elastic, always pre-stretch it. When installing the elastic, use a wider zigzag. I have found a stitch length of 3 and a stitch width of 5 to be very strong and stretchy.
If your elastic seems to have stretched out after it is sewn to the leg holes, give it a good press with lots of steam. Keep the iron on a low setting to protect the swim material, but use lots of steam. The steam will return the elastic to its original size.
Rash Guard
Now for the pattern hack. Hacking Plumeria to be a rash guard is very easy. Simply cut the front and back side seams as straight lines that extend an inch beyond the side seams of the pattern.
After assembling the suit, hem the bottom up 1 inch. Use wash-away wonder tape to tape the hem in place, so it doesn’t shift when sewing. To do this, simply stick the tape to the wrong side bottom edge of the rash guard.
Remove the paper lining on the double stick tape, and fold the hem 1 inch to the wrong side.
Board shorts
The board shorts are a little more complicated, but totally worth it, so hang in there with me. Basically we just need to cut the bottom of Plumeria and match the rise to the rise of the brief lining of Monstera. First, measure the rise of the back panel piece of Monstera. The rise is the longest length on the piece. Use this measurement minus ½ inch for your rise on the back piece of Plumeria. Match the side seams and cut the front out with the same length of side seams.
Sew the side seams and add the gusset lining (steps 4-6 of Plumeria).
Follow steps 30-32 of Plumeria to attach the elastic. When attaching elastic, it is helpful to start by clipping the area that is not supposed to be stretched. Then grab the fabric by the end clips and stretch the elastic to match the leg hole
When it is evenly stretched, use your thumbs to pinch the elastic to the swim material and clip in place.
Now, the front rise needs to be shorter than the back rise, so we need to taper the back rise down to the front rise. Fold the back piece in half and mark 1.5 inches on either side of the fold.
Line up the mark you just made with the highest point on the top of the brief lining side piece from Monstera.
I used a projector, but this could also be done with a paper pattern piece.
Making sure your pattern and fabric remain straight, cut along the top diagonal line, stopping when you get to the end of the brief lining piece. Starting at the other mark that you made, cut the mirror image along the opposite side of the Plumeria piece. You should end up with a graded piece removed and a few inches in the front still attached. Cut straight across the front.
Now, you can follow step 17 to attach the lining to the shorts. The only difference will be that your lining will be a bit smaller than the board shorts. Make sure to quarter the lining and the shorts and match the quarters. Then stretch the lining to match the shorts.
Make sure that every time you sew along the top of the shorts (steps 18-20), you stretch the lining to eliminate any wrinkles or puckers in the board shorts fabric.
Finish up with steps 21-26, and there you have it! Board shorts for girls!
Now go grab your favorite swim patterns. Plumeria and Monstera will be 20% off during the month of June with the promo code Swim20! And if you sew either pattern during June and post a picture of it on Instagram and the Sunflower Seams Facebook Group with the hashtag #LearnwithSunflowerSeams, you will be entered to win a free pattern of choice!
Happy Swim Season!
