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An Alternative Way to Finishing A Bra Cup Seam

bra making

I used a new technique to finish the cross cup seams when I made Eleanor Sykes. Normally, I serge with poly or woolly nylon thread, or I use this method. The latter mimics tricot tape I’ve seen on many RTW bras. It’s hard to source and I’ve tried several times to make with no success. This new way is the closest I’ve come and I think it’s pretty darn similar to the real thing. As a follow up to that post, I’m showing you how I made it.

Supplies: bra pattern with a cup seam, 15 denier tricot, polyester thread, scissors and fabric/lining suitable for your bra
For this tutorial, I’m using a self-drafted partial band bra pattern that has a horizontal cross cup seam, but this method can be used for almost any bra with a cup seam. Diagonal and vertical are just two other silhouettes that would work. Also, I’m using a jersey knit underlined with a stretch mesh. Normally, I wouldn’t use this fabric for a bra cup, but I chose it because it would show stitches well.

Step One

Cut self fabric and lining for bra cups. I spray basted layers with Odif’s 505 temporary spray adhesive prior to cutting, but you can cut separately. After, cut strips of tricot on the bias. I like to cut my strips longer and wider than needed and trim to the exact size during sewing. Believe me, it will make your sewing life a whole lot easier! The seam allowances on the bra cups I’m using are ¼”. The binding will be turned/flipped three times, so technically, my binding should be a little more than 3/4″ to account for turn of the cloth. I made it 1 1/8” instead to give me wiggle room. As you can see in the photo, the length is much longer than what is needed.

Step Two

Sew upper cup, lower cup and bias tricot together at cross cup seam. Since I’ll be pressing the seam allowances down, I sew with lower cup on bottom. If you’ll be pressing the seam allowances up, sew the opposite. In either case, bias strip should be on top when sewing.

Trim and grade seam allowance. Because the binding will be pressed down, I cut the upper cup seam allowance 1/16” shorter than the lower cup seam allowance to avoid an indentation on the right side. You can see it here.

Step Three

Wrap the bias strip around to the other side and sew exactly on the seam you just sewed. The lower cup should be on top now. After, trim super close to the stitching like this. Now you can thank me for making your binding wider than it should be!

If you’re wondering what scissors I’m using to trim, they’re called duck-billed, and they’re one of my favorite bra making tools! The paddle-shaped blade serves as a shield and a guide, which makes it easy to trim and grade seam allowances neatly. You can read more about them as well as where to by in this post.

Step Four

Press binding down. On the right or the wrong side – whichever is easier for you –secure binding in place by stitching 1/8” or less away from the binding’s lower edge, or if you’re sewing on the right side, approximately ¼” from seam.

Here is a close up of what the binding looks like and you can compare it to a RTW.


  1. Reply


    Love it! Will work great for so many other applications, too. Cant wait to give it a try!

  2. Reply


    That is sooo cool 🙂

  3. Reply


    Hi, would this method be used for unlined lace bras? or would it be your other post ‘http://www.madalynne.com/bra-making-alternative-way-finish-cross-cup-seam’ ?

  4. Reply

    Isabel Vanzieleghem

    Oh wow, Madalynne! Thank you. Great tip!

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