Video: An Easy Seam Tape for Bras

How to make an easy seam tape for bras | Cloth Habit

There are many ways to finish bra cup seams and I love experimenting with different techniques. Most of the time I line bra cups with a sheer lining because I love the way lining feels and it’s an easy, neat way to hide cup seams. You can even line the insides of foam cups if the seams are bothering you.

But what if you don’t want a lining? Enter seam tape!

This is my favorite way to cover and neaten foam cup seams, and it’s also a common treatment for ready to wear bras that don’t have a lining, both foam and non-foam. I’ve had a lot of questions about how I make seam tape for my foam bras (like this one) so today I’m going to show you! This weekend I was working on a new bra and I shot a spontaneous video to show you exactly where this mystery tape comes from, and how I use it.

Hilarious video note: before anyone shouts at me, I realized after I finished I was pronouncing “tricot” wrong. It’s one of those words I often write but rarely say out loud. I’ve heard some (American) sewists pronounce it “TREE-coh” and others “tree-COH” but never “tree-COOO”.

Supplies mentioned in video:
Sheer tricot (see below for sources)
Fabric spray adhesive
Wonder Tape

Where to Find Tricot

I don’t buy premade tape but cut it from sheer tricot, which can go by many names. What you want to look for is any kind of sheer nylon lining. I don’t know of any sources where you can buy tricot tape that’s wide enough to fold into thirds and still cover the seam, but why buy premade tape when cutting your own is so easy? I use the same tricot to line cradles, bridges or cups, so I always have some extra to cut out seam tape. It takes me all of a couple minutes with a rotary cutter and a ruler!

Sheer cup lining: Bra-makers Supply, Blackbird Fabrics (what I often use)
15 denier tricot: Sew Sassy,, and many many more (Google it! it’s also called nylon chiffon by some retailers)
40 denier tricot: Sew Sassy

Note that 40 denier tricot is more opaque and a little bit weightier than 15 denier. It can be easier to work with if you dislike sewing sheer nylon, and it makes a suitable cup lining or seam tape material.

In case you were wondering, the bra in the video is a new pattern! I’ve been taking my sweet time refining this pattern, and I’ll definitely be showing you more about it in the New Year. It’s also the bra I was using for my second dyeing video, which I promise will be coming soon. I made a big mistake when filming (I chopped my head off!) and had to go back and refilm.


  1. Ms. McCall says:

    Fantastic post! By the way, the 15 and 40 denier tricot that I got from Sew Sassy was very stretchy in one direction, and disappointingly not really any use to me for cup lining (large cup here).

    • Amy says:

      I agree, 15 denier tricot is very lightweight, and usually has a lot of give in at least one direction. I definitely wouldn’t use it as a support fabric but if you already have a firm cup fabric it can make a silky lining or just good thing to have around for stuff like seam coverings! If you use the 40 denier in the non-stretch direction is makes a good bridge and cradle lining. The kind I have in the video might be what you need if you are looking for a cup lining—it is really firm.

  2. Olga says:

    Amy, thank you for this tutorial. I’ve been using satin ribbon so far, but I found it rigid for the curved areas. Also, I was looking for ways to use the edge of the lace at the top of the cup when cutting the top piece in foam as well. I’m not experienced enough and I’ve only seen bras having that pretty edge at the top of the cup when no foam was used under. I like the way you combined the two in your bra, thank you for the inspiration. Did you handstitch the lace to the foam, or there was no need for it?

    • Amy says:

      Hi Olga,

      good question! I use my machine to stitch the lace down in two spots, sort of evenly spaced across the neckline. If I didn’t the lace might stretch and drop down below the foam. I stitch from the inside, on the foam side so I hit the ditch right where I overcast the edge of the foam, just taking 2 back and forth a couple of times. It’s sort of like a tiny bartack if that makes sense! I got this idea from ready to wear and it’s nearly invisible. On this post I did something similar for a cup that had a tricot lining instead of foam: You can see the tiny tack in the photo that has the word “tack” on it.

  3. Anne-Marie says:

    Thank you! This is an excellent tip. As for pronoucing the French word tricot, there is not tonic accent on either the first or second syllable. You simply say tree-coh. Witch as you know is the French word for knit. I love your website and patterns. The long Watson is one very faithful companion in my new life as home bra maker . Regards from Montreal

    • Anne-Marie says:

      Don’t you love auto-correctors. All appologies for the word Witch that should have been Which. I was unable to erase my initial comment to replace it by a corrected one.

  4. Melissa says:

    I haven’t had a chance to watch the video yet, but I am so excited to hear that you are working on a new pattern! Can’t wait to try it!

  5. Brandy says:

    I’m curious that you were able to dye the nlyon fabric. Does it dye as easily as cotton and linen? If so, this would help me in making a decison on colors, since Sew Sassy just has a few choices. Did you buy white to dye Navy?

    • Amy says:

      Hi Brandy, I dye most of my lingerie fabrics! And yes, I buy white fabrics and elastics to do this. Nylon dyes easily but not with the same types of dyes that work on cotton and linen. Have a look at my first tutorial on dyeing here – It explains the kind of dyes you would use and what dyes work best on certain fibers.

  6. Niki says:

    What type of cup foam did you use for the cup in this video? I’ve been playing around with foam from different places and so far have had the best luck with the one from bra-makers supply, but always looking for new options.

    • Amy says:

      Hi Niki, I *think* it may be foam from Bra-makers Supply, but they had a couple of different styles when I last sourced from them. One is firmer than this one. I’ve tried a lot of different foams and like firm foams for bras that really need to hold (like a strapless bra) and softer foam for every day bras.

      • Niki says:

        I also prefer firmer foams for most bras and have been having trouble finding one I like, any recommendations?

      • Amy says:

        Hey Niki, the Bra-makers Supply foam is the firmest I’ve tried. I think they call it “Poly Laminate Foam Padding”.

        Most of the suppliers I’ve used offer swatches if you want to just touch them. (Because I know foam is expensive!) Spandex House sells a variety of foams—some of them more appropriate for padding outdoor gear but some quite good for bra making–and they will actually sell you a swatch card full of them. You have to call and order, but that’s another option if you want to try something other than BM Supply.

  7. Tammi T says:

    Great video. Just one question, couldn’t use a bias tape maker to help fold the seams inward or is the tricot too soft?

    • Amy says:

      Hi Tammi, It’s definitely too soft! Nylon is nearly impossible to press and tricot doesn’t hold creases or folds, but believe me I have tried everything to get it to do that. In the past when I sewed this tape without using glue, I spent a lot of time trying to keep it creased with my hands as I was sewing it, which makes for really finicky and frustrating sewing.

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