TUTORIAL: HOW TO SEW A BUILT-IN BRA (WITH CUPS!)

by Daughter Fish

How-Do-You-Do-Bardot Maillot (left), Bubblegum Top (right)

For the past year, I’ve been sewing built-in shelf bras, with cups, into maillots (unitards), t-shirts, and tank tops. My original inspiration for this came from several vintage garments—a dress and bathing suit—that I wear regularly, which have built in bras. For me, there are several advantages to building a bra into a garment. I like to design shirts with dramatic, low back lines that would usually show a traditional bra.

Built in bras also just happen to be comfortable.  And in contrasts to the simple shelf bras in sports tops, adding cups to a shelf bra also provides a pleasing silhouette (no tube boob!).

A few other bloggers have asked me to share my technique. I can’t say that it’s the prettiest or most sophisticated. I’m sure that some of you out there with lingerie sewing experience could add a few pointers on materials and techniques.

What I can say is that this tutorial is relatively easy, and you can do it on a home machine. My tank top pattern happens to be self-drafted, form-fitting, and  low-backed.  If you were to do this technique with a looser tank, you’d just need to make the bra section tighter/more form fitting. I sew most of my seams with a serger, but you can easily sew a stretchy tank on a regular machine using a stretch stitch.

Here’s how I do it:

Tools

I like to use a soft cotton-lycra blend knit (it won’t pill like rayon or bamboo knit), 1 inch wide elastic, and sew-in bra cups. Make sure the bra cups are your appropriate cup size and that you like the shape they give you. Slightly padded cups will keep your girls from “tuning in Tokyo.” I buy cups in the garment district, where there are lots of different shapes to choose from. If your resources are more limited,  Dritz makes cups sold at JoAnn’s.

The elastic should feel comfortable against your skin. I like to cut everything out on a cutting mat with a rotary cutter and sharp scissors (but of course!). For my pattern, I drafted a simple sloper based off of my maillot pattern.

When cutting out striped jersey on the fold, I line up my stripes and pin them before cutting out my pattern. This will ensure the stripes on the shirt are indeed horizontal, and not listing to one side or the other.

Step 1: Cut the pattern pieces

Cut out your front and back pattern pieces (3, 4). For the bra pieces (1, 2), I use the same tank top pattern, but just use the top third portion. Measure from your shoulder to under your chest (or to where you want the bra to hit) to gauge how long to cut the bra pieces.

Note: I generally use the same jersey fabric as the shirt for my built-in bras. This results in a very soft, cami like bra that stretches exactly like the tank top. When the fabric stretches, the bra usually ends up hitting me around the lower rib cage. If you want the bra to hit you right under the boobs, adjust for length. For more support, you could use polyester swimsuit lining or another lining fabric with more structure (or even wicking abilities….Maddie of Madalynne has some good info on this for sports bras).

Step 2: Position the cups

Hold the front bra piece up to your chest, stretching it across your chest as if it were sewn to the back piece. Take note of where your girls land on the front piece; this is where you’ll want to position your bra cups. (I realize that’s not very scientific!)

Lay your front bra piece on a flat surface, wrong side up. Position your bra cups on the front bra piece. Make sure the bra cups are positioned so that they’ll nicely fit your boobs once you have the bra on. I always hold the cups up to my girls  to get the right angle, and then mimic that placement on the front bra piece. Generally, I place the top of my bra cups about 1 inch below the neckline; the center of the cups generally fall about 2 inches below the V of the neckline. I place the cups 1/2 to 1 inch apart. (I use a B to C size cup.)

Experiment with the placement of the cups and pin them in place. At this point, you can again hold the bra front to yourself to see if the cups are close to where they need to be. Just remember that the cups will stretch away from each other, once sewn in, so it’s sometimes better to have them closer together (so you don’t end up with bra cups on the side of your body!).

Step 3: Sew the cups

Sew the cups onto the front bra piece, just around the edge of the cups. If you’re not sure about placement, baste them on with a long straight stitch, and then hold the bra piece to your chest again to make sure the cups are falling in the right spot. Sew the cups on with a stretch stitch. And don’t be afraid to cop a feel on the cups! It’s the easiest way to rotate the pattern piece as you sew.

When you’re finished sewing the cups, your pattern piece should look like the above.

Step 4: Cut away the excess fabric

Cut away the fabric that’s covering the inside of the bra cups. I like to snip a section toward the middle of the cup and cut away from there.

Step 5: Sew your bodice and bra pieces 

Right sides facing, sew your front and back bodice pieces together, and your front and back bra pieces together. At this point, it’s a good idea to slip on the bra to see if it feels like it will fit snuggly (keeping in mind that you’re still going to attach an elastic band around the bottom).

Step 6: Attach the elastic band

Wrap the elastic around your ribcage, just below your breasts, stretching it slightly, so that it feels snug but comfortable. Cut the elastic to this length. Butt the ends of the elastic and use a zigzag stitch to secure them.

Divide the elastic into fourths and mark with pins. Divide the bottom of the bra into fourths and mark with pins. Pin the right side of the elastic band to the wrong side of the bottom edge of the bra (at the four pin marks). Using a stretch stitch or zigzag, sew the bottom edge of the elastic band to the bottom edge of the bra, stretching the elastic between the four marks. Fold the top edge of the elastic to the right side of the bra, so the elastic band lays flat. If the band doesn’t lay flat, use a hot iron to press the fold where the band and bra meet. Sew the top edge of the elastic band to the bra.

*Note: This explanation for sewing on the band is a little simplistic. You may already have a preferred method for finishing the band in a more professional way. Just note that sewing the top and bottom edges of the elastic to the bra will make the bra more secure. You might also want to try the bra on at this point to make sure it fits the way you want it to. If it’s not tight enough, and you feel you won’t have enough support, take in the side or shoulder seams to tighten everything up.

Step 7: Pin bra to tank

With the tank top inside out, and the bra right side out, slip the bra over the tank top. Line up the shoulder seams of the bra and tank and pin in place. Line up the under arm seams of the bra and tank and pin in place.

Step 8: Baste bra to tank

Baste the neckline and arm holes of the bra and tank together. This will keep the tank and bra from slipping apart as you finish the neckline and arm holes.

Step 9: Finish the neckline, arm holes, and hem

I like to finish all edges with folded strips of fabric. I find this gives the cleanest look that I can achieve on my home sewing machine and serger. For this tank top, I cut the bands so that one white strip runs down the center of the band. Once the band is folded in half, there’s just a thin peep of white at the top edge of the band.

For more information on finishing edges with fabric bands, check out this great Threads tutorial video on a neckline binding. The same technique can be used for finishing the arm holes.

Step 10: Wear with attitude!