Making a Foam Cup Bra: Part 1

This summer I have planned a few foam-lined bras for my wardrobe. One of these is going to be strapless style I can wear comfortably underneath my low-backed tops and dresses. Comfort being a key word, because I have never found a strapless that doesn’t make me squeam.

I like using foam linings when I want a supporting bra but also want to use an outside cup fabric that’s really light or stretchy. For example, I made these bras from rayon jersey scraps because I loved the print, and the foam gives them shape and support.

Making a Foam Cup Bra | Cloth Habit

I’ve been promising a tutorial on these forever, so here we go! Over the next three posts, I’ll be sharing how I adapted a bra pattern for a foam lining, along with a few construction tips. Some of these techniques can also be used for making foam cups to insert into a swimsuit or bodysuit, too!

Today I’m going to cover materials…

Materials You Need

  • bra pattern
  • sheet foam, approximately 1/8 yard
  • materials and notions for making one bra
  • sheer or light tricot lining (optional, for making seam tape)
  • manila folder, cardstock, or sturdy paper on which to re-trace some of your pattern pieces (avoid tissue–it is impossible on foam!)

Patterns: To follow along with these tutorials, you can use any underwired bra pattern that fits, provided the cups fit in non-stretch fabric and the bra is a full frame (aka full band) style. Frameless bras require slightly different pattern adaptations.

For cup fabrics, the world is your oyster. You can try a lycra/spandex type fabric, lace, any knit, or even something like a satin woven! For this tutorial I chose a blush stretch silk charmeuse, scraps of which were in my stash.

Making a Foam Cup Bra | Cloth Habit

Where to Buy Foam

Sheet foam suitable for bra-making goes by a few different terms. These foams can have either a brushed or satin tricot finish on the outside. Sometimes they have some spandex/lycra content for a little bit of “give”. They can be anywhere from 2-5mm thick (usually around 1/8″), and some are spongier than others. I’ve sampled foams from four different retailers, and in my experience most of these them adapt to the body and eventually flatten a bit with wear.

Here’s where you can find them (links go to the page with sheet foam products):

  • Bra-makers Supply (“laminate foam” and “stretch spacer foam”)
  • Make Bra
  • Fabric Depot Co. (“tricot-bonded poly filler”)
  • Sewing Chest
  • Spandex House (spacer foam–I recommend asking specifically for a foam for bra-making, as they carry various types)
  • Sew Sassy (“polylaminate foam”)
  • Sewy (“spacer foam”)
  • Spandex World sells spacer foam but I’m not sure if it is suitable for bras. (I’m guessing they are more appropriate for surfwear and running pants.) You may want to ask for samples.

Sew Sassy and Fabric Depot also sell a poly fiberfill fabric. These are a wadding bonded to a satin-y tricot, and offer many of the same benefits as sheet foam.

*Interesting factoid: Spacer foam is a distinct type of foam that looks and behaves a lot like laminate foam, but the foam is not heat laminated to tricot. The foam core and outer layer are knitted together on the same tricot machine, which allows for a more “breathable” foam. Some lingerie brands even market this technology in their bras.

Consider the Silhouette

If you have a bit of extra foam to play with, might want to sew up a trial cup in foam to see what shape it takes. I find this kind of fun, actually. The pattern may have a good fit and shape in softer fabrics but in foam the shape will be slightly different. Sometimes I even tape together a printer paper version of my cups to get a rough idea of the silhouette:

Making a Foam Cup Bra | Cloth Habit

I added a second seam to the bottom piece of a two-piece cup for a rounder cup. Adding this seam is actually very easy!

Of course paper isn’t going to tell you everything but it’s still a good way to visualize in 3D. I also tape up a paper cup and hold it up to myself so I can see if my strap attachment point is located in a comfy place.

Tomorrow I’ll share my pattern adaptations and get started on the sewing!

p.s. Just in case anyone asks–this tutorial is not for a seamless bra or a push-up bra. There are many styles and techniques to foam bras so hopefully this tutorial will give you ideas you can experiment with!

See more posts in the series Make a Foam Cup Bra.

35 comments

  1. Susan says:

    Aaaah I love that this lets you use whatever lovely stretch fabrics you can get your hands on, rather than just needing the ones that would provide the necessary support. This is a well-needed tutorial series Amy — I’ve only ever heard how impossible it is for home sewists to make foam cup bras! 🙂

  2. lsaspacey says:

    If possible, can you show pictures of the different foams (only if you have some on hand, of course!) You listed so many different types and even if we can’t touch perhaps the looks will help when we’re out shopping for some. Ex. what kind is being cut in this post? Thanks!

    • Amy says:

      I’ll see what I can do! Sometimes it’s hard to get these fabrics to show up well in pics, especially because they are all nude-ish pale colors. I hope I didn’t overwhelm you with options. All the foams I have listed are very similar–just different terms. These aren’t fabrics you’ll be able to find when you’re out shopping so I recommend trying one of the sources above. The foam I am cutting above is from Sew Sassy.

      • Louise says:

        Do you have a recommendation on 2-way vs 4-way stretch spacer foam for making the cups? (i am using this for swimwear bra cups).
        Thanks!! 🙂

  3. Kathy says:

    I love the black with white polka dot bra! I just finished a couple bras (non-foamy ones from a TNT pattern) and am going to watch this foam cup tutorial as you go. What pattern are you working with here for this? A purchased pattern or one you worked up? Have you had good foam bra results with cups that only have one vertical seam (I really like KS3300, I’ve tweaked it to fit me really well with lace/fabric cups.) Would you say adding another seam along one of the cups provide a better shape? So many questions! Thanks for sharing.

    • Kathy says:

      Wait, this looks like the Pin Up Girls full band pattern with an extra seam and some tweaks? I have had success with this pattern as well.

      • Amy says:

        Hi Kathy! The polka dot bra was a frankenpattern of sorts. Katherine of Sew Blooms drafted the original and I tweaked it based on my personal patterns. The bra I’ll be using for the sew-along is very similar but I drafted it afresh for a better fit.

        And your previous question… I have had good results with a foam bra with only one vertical seam. You can do the KS 3300 but it is a partial band pattern. There are some techniques you can do so that you don’t end up folding the foam back on itself with the channeling. I won’t be showing those but it’s worth an experiment! (I took apart an old t-shirt bra to see how it could be done… cool stuff going on in there.)

        I think just about any bra pattern can be tweaked to work with foam. It’s really just a way of lining a bra. As far as adding additional seams for shape, that’s up to you. Adding a vertical seam to the lower cup of a pattern that only has a horizontal seam, like the Pin-up Classic, will give it a bit of a rounder silhouette.

  4. Brigid says:

    Yay! So excited for the next steps! Just a question, I have also been thinking about making a strapless bra. Could you do a tutorial on how to adapt a pattern to be a strapless bra? Thanks!

    • Amy says:

      I’m excited to try a strapless. I have some experimenting to do this summer and I’ll be sure to share my experiences.

  5. Joanne says:

    I’m really excited for this series! I don’t know that I’m “ready” to jump into sewing bras, but I’m definitely tempted! I’m assuming that these foams would also work for supporting strapless dress bodices? Specifically, I’m thinking I would like to revisit Gertie’s bombshell dress and make a bodice that has a little more cup support than what I ended up using last time (I think some sort of batting?) Considering that the bodice cups don’t have underwire support, but that spiral steel boning supports the bodice all around, it would kind of work like a long-line bra, right? Am I thinking this through right?

    • Amy says:

      Hi Joanne, using foam instead of batting is definitely an option. I don’t know how much more support the foam itself would provide, but there’s certainly a lot of fun to be had with the bombshell dress. Another option is using bra cups that fit you and work them into the dress… sort of like making your custom fit bustier to fit into the dress. No reason why you couldn’t add underwires, either!

  6. Katherine says:

    I comfortable strapless bra is on my to-do list as well. All the strapless bras I own are partial band bras, which doesn’t make sense to me. I think a full band, and possibly will be much more supportive.

    • Amy says:

      Yeah, I agree on the full band. The band is an important lever. I’m going to think through the materials a bit… it might be plain-looking but I really want comfortable.

  7. Margo says:

    Thank you for this information! I’ve been wondering about adding foam to home-sewn bras before but didn’t know how it worked. These resources are great! I think I’ll get some of that fabric from Sew Sassy.

  8. Nancy S. says:

    What a wonderful tutorial. Your comment about the usable fabrics made me remember a wonderful “set” I had back in the late 60s. It was a beautiful satin type fabric with a deep navy background and violets everywhere. I had the bra, the half-slip and the panties and loved that set. Maybe I c an recreate it with these wonderful instructions. I just want to ask if an extra piece of foam can be added to the bottom of the cup for a little lift? (Things do sag after menopause, sadly). Thanks. Nancy

  9. Fleurecarlate says:

    Hi Amy, will this technique work with your Watson bra pattern? Adding foam under the lining and using one vertical seam? Thank you!

    • Amy says:

      Hi, I haven’t tried it. Normally I only use foam when a wire is involved and the Watson is wireless. Also, since the Watson’s bra cups have stretch reduction, you would need to play around with fit since foam doesn’t stretch (if it does, very little), so the results will fit quite differently than the intended fit.

  10. Susan says:

    Hi! I’m a breast cancer survivor and am trying to make an insert so I can look normal in a dress for a wedding. I purchased a well fitting bra but I need to make beast forms to fit inside. What do you suggest for materials? I am planning on sewing it into the bra. I am an experienced seamstress. Thanks in advance for your suggestions.

    • Amy says:

      Hi Susan, I don’t have experience in making breast forms but I imagine it is possible to make them from the sheet foam I am using in these tutorials. You could sew several layers into each other until the cup is filled out. To make a breast shape, however, you’d need a cup pattern that had similar volume as your bra. I hope this gives you some ideas and wish I could help more!

  11. Kitt says:

    Clarity, my kingdom for bit of clarity. Thanks for clear and helpful information. Looking forward to my next lesson.

  12. Sasha says:

    Hello,
    I can’t finde any where diy T-shirt bras, for very small brest. Only bralets. Is that possible for you to give any advice for us tiny brest girls) For a COMFORTABLE T-shirt bra.
    Thank you)

    • Amy says:

      Hi Sasha,

      Many underwired bra patterns can easily be turned into a t-shirt bra by adding a foam lining, which I demonstrate in this tutorial series. Some patterns are even built around foam linings and offer very small sizes. I don’t have space to list all patterns here but you may want to take a look at my resources page: https://clothhabit.com/bramaking-resources/ Quite a few of the shops and designers I list there offer patterns in different sizes.

      I happen to be small-breasted so hopefully you can get some good ideas from my projects. The bra I was making in this post is a pattern I drafted myself. It isn’t too difficult to alter an existing bra pattern to get what you want. Because bras are so close-fitting, altering a pre-made pattern for a good fit or a slight change of style is very much a necessary part of bra making, no matter what how big or small 🙂

  13. veronicade la rosa says:

    me encanta la pagina y quiero hacer uno igual pero necesito el patrón con medidas ya que no soy una experta

    • Amy says:

      Hi Veronicade,

      I wrote this tutorial to show how you can transform any underwired bra pattern to use foam linings. You don’t have to use this specific pattern. The one I used in this tutorial is not for sale but there are many others like it. You can look here for some shops that sell patterns: https://clothhabit.com/bramaking-resources/

  14. Anna Boon says:

    Hello Amy,
    I just wanted to let you know that the links to Fabric Depot Co. and Sewing Chest are broken(as of Jan. 16 ’17), at least when I tried them. I also have greatly appreciated your tutorials and sew alongs as I’ve been exploring making my own lingerie. Thank you so much!

    • Amy says:

      Hi Anna, thanks for letting me know! I fixed those two links but of course it would be hard to constantly update ever-changing online retail links after 3 years. 🙂 As far as I know all of these shops still carry the same foam products!

      • Anna Boon says:

        You’re welcome Amy!
        I understand about the retail products – so no worries there. Just having a place to start is a huge blessing.

  15. Lill says:

    Hi. Is it possible to make the Watson with a foam cup? I really like that pattern, but I never wear a bra without padding. Do you have any tips on how to implement foam in to the Watson?

    • Amy says:

      Hi Lill, because the Watson uses stretch fabric to fit around the breasts (i.e., it has negative ease), foam will change the fit so takes some experimenting and trying different cup sizes. I wish I had more advice! I usually recommend when trying any new bra pattern to use the patternmaker’s recommended materials and then with that knowledge figuring out what else can be done. I haven’t used foam because I didn’t design it to work with foam… not that it can’t be done but I’m a believer in creating different patterns for different purposes. 🙂

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