Bra-Making Favourites: Cut and Sew Foam & and Fold Over Elastic!

Hi All! I’m Erin, or Emerald Erin, you might know me from my blog The Sewing and Life Adventures of Emerald Erin! I’m mostly a bra-maker or swimsuit sewist- but I like to dabble in lots of creative endeavours! You also might know me from my Bra-A-Week Challenge– where I sew a bra or swimsuit every week and post it on Sundays along with all of your lovely bra submissions! I’m also a full-time blogger, custom bra/swimwear maker, sewing instructor and pattern designer who is in the middle of launching a business!


I’m so excited to be here doing a guest post for Lingerie sewing month- especially since every month for me is lingerie sewing month! And I thought that I would share two of my favourite bra-making materials and how I like to sew them! First I’m going to start with cut & sew foam, also known as pre-finished foam padding, or polylaminate foam padding.

IMG_2213 If you’ve already worked with this foam then you’ll know that it is lovely! And it gives you the coverage and support of foam, but in your unique shape- unlike the molded foam cups! I’m going to show you how I like to sew it on this sample cup- remembering to cut out your pattern without the interior seam allowances- since you are going to butt your fabric together and sew it.

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Now this is my favourite way to sew seams in cut & sew foam. I like to use a ‘satin stitch’ because I find that it is the nicest and strongest finish.  And on my machine that is a simple zig-zag stitch with a 4 width and 0.5 stitch length. With that stitch I butt my pieces together and stitch them together.

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When you’re sewing them together, you’ll notice that this stitch almost squeezes your fabric together nice and tight- making it look like there isn’t a cut in the fabric in between. This stitch can take a little practice, and you want to make sure that you don’t have too heavy of pressure from your foot and your feed-dogs are moving the fabric through nicely to prevent any stretching in the seam- which you don’t want! Sometime it can even help to push it through a little bit. Now the alternatives that I’ve seen to this stitch are a regular length zig-zag (this sample one is 3 width by 3 length on my machine) or a 3 step zig-zag (this sample on is 4 width by 1.5 length on my machine). What I notice is that these stitches tend to leave more dimples and unevenness that will show through your outer fabric, rather than the satin stitch which looks a lot more even.

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The other important par is the strength- when you pull on all the seams, the regular and 3 step zig-zags tend to pull apart and make gaps, and the satin stitch stays strong and together!


So here you can see an example of a cup that I’ve made up with the satin stitch, and how smooth it is around the curves!

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It really makes for a nice cup! All of my every-day bras are made with this foam and this stitch and I find that it wears wonderfully and is nice and smooth and soft against the skin!


Now on to my second favourite bra-making material which is fold over elastic! or FOE for short!

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There are lots of different types of fold over elastic that you can get- different widths, shiny sides, matte sides, picot edge, pre-folded, flat. like working with this flat 3/8″ fold over elastic (3/8″ when folded) and I prefer the matte side to the shiny side. I like to sew on my fold over twice, because I’m not very good at keeping it sandwiched around my fabric, and I find that it’s easier and quicker to sew it on twice! For this I like to use a very small zig-zag stitch, which on my machine is a 1 length by 1 width (I have a thing about same length/width zig zags lol).

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I start with the wrong side of the fabric facing up and I line up the centre of the fold over (you can usually see the line where the centre break is) just on the outside of the edge of your fabric. Once you get sewing you can check to make sure it’s in the right place by lifting it up and lining it up just off the edge. You can also pin this if you like- but I find it just as easy to manoeuvre it as I go. Also I don’t like to pull on my elastic as I go- just keep it finger tight- so it’s not completely slack, but just a slight hint of tension.


I sew right on the edge of the fold over- being careful to stay on the fold over and not go over the edge into your fabric- because you’ll see that from the front if you do!  Then when you flip it over to the right side of your fabric you’ll see your stitching through- which is a good guide to follow when you stitch down your other side.

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You’ll also notice that you can see that centre break of your fold over elastic right over the top edge of your fabric- which means that when you fold it over it will be right where you intended your fabric edge to be- no taller, no shorter! If you’re working with foam, like I am in the example I would recommend trimming some on the fabric above your seam to reduce bulk- you won’t have to do this if you’re using a really light or lacy fabric.

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Then all you have to do is fold your elastic over where it naturally wants to fold along the centre line, you can pin it if you like, or not if you’re comfortable doing it with no pins. But the important thing is that you use your stitches from the other side as a guide and that you make sure to cover them with the elastic on the right side. Then you’re going to do the same stitch and sew right over top of your old stitching on the edge of your elastic. And voila!!


You have a beautifully finished edge with very minimal bulk! On the front it will have a single line of small stitching and on the back it will have an overlapping double line. And I find with this zig-zag that it has enough stretchability that I’ve never had it pop before. Here are some example of my foam and fold over projects- you can see it’s definitely a fav!

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This is a perfect example of the cut and sew foam cup with a satin-stitch and nice fold over elastic on the top- and you can see how it all just blends beautifully with matching threads! This is my bra from Week 8!

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This is an example of a fold over project that I did with a double strap- where I used fold over for the neckline edge and the underarm edge on a bralette and continued it up to straps. To make it a little more supportive I added some non-stretch ribbon on the inside of these straps and that added some good stability. This is my bralette from Week 9! I also use a similar technique with fold over binding- that I like to use for contrasting edges on my swimwear!


The possibilities with this are really endless and I keep finding new ways to apply it. This is my swimsuit from Week 18! Do you like working with cut&sew foam or fold over elastic? What are your favourite bra making materials? Also don’t forget to come over and check out my blog! I’ve got lots of fun things going on right now! You can join the Bra-A-Week challenge and be inspired by all the other lovely submissions! Or you can follow me on my bra and swimwear adventures!  I’ve recently gone into the bra and swimwear business full time! So you can join me as set up my new studio, launch my online store and figure out my creative business! Yay! Hope to see you over there!

xo erin

45 thoughts on “Bra-Making Favourites: Cut and Sew Foam & and Fold Over Elastic!

  1. Congratulations on the launch of your new business Erin! And thanks for such a great post, I’ve often steered away from using foldover elastic (I’m too fond of pretty picots!) but you may well have swayed me into giving it another go 🙂

    1. Hi Elaine, No unfortunately this foam is 100% polyester and very difficult to dye- I bought my foam to match my fold over elastic. I got mine at Bra-maker’s Supply in Hamilton, Ontario- she has a nice selection of colours, with matching fold over elastic. Although I find that having a nice peachy-colour and a black goes under most things nicely 🙂

  2. This post couldn’t have been more timely! I’m just looking into trying cut and sew foam for the first time 🙂 What foam thickness do you usually prefer? It looks like I can have 2mm or 5mm (would have preferred something in between!) and I’m really not sure which way to go on this one…

    1. Hi Maddy! On this I used 2.5mm thick foam, and I would say if you’re options are 2mm or 5mm, I would go with the 2mm, especially since you are more well-endowed, and I’m assuming you don’t want it for adding to your cup size, more for the smoothing and shaping effects!

  3. Hi Erin , thanks for the tips, as you know I have tried the cut & sew foam and love it. but I just needed that little tip about the stitch length, and love the look of the fold over edge, thanks again, Rebecca !

    1. Thanks Rebecca! It took a while to figure out the best way to sew the foam, but I’m so happy with this stitch. I’m glad you’re getting into the fold-over elastic too- it’s such a nice edge!

  4. Great tutorial Erin! I love working with cut and sew foam and fold over binding too! I usually 3 step zig zag my cups together, but I am going to try the satin stitch – it really looks much nicer! See it is true- old dogs CAN learn new tricks! 🙂
    Good Luck on your new adventure!

  5. Those stitch samples are so helpful to see, Erin – I know I’ll be coming back to this post for reference when I try sewing with foam! One question: Are there certain patterns that work better/worse with foam, or can you use pretty much any pattern as long as you take out the interior seam allowances?

    1. YAY! Thanks Gillian, I would recommend foam for most all bra patterns- the only thing that you have to watch with some patterns is combining it with lace. It works well under lace, but if you want sheer -only lace- part of your upper cup- (like the Shelley from Pin-Up Girls or Rebecca from Sewy) Then it will leave quite a ridge where you go from fabric and foam, to only sheer lace- which isn’t a problem for fit- more for how smooth your cup is, and how much it will show that ridge though a t-shirt. So I find for myself that it has to be a bit of an all or nothing decision with foam. But I find it solves so many fitting issues, especially with lower necklines on bras, and is so much better for keeping a nice shape!

  6. Great tutorial! I recently took a class in “cut and sew foam” with Beverly Johnson and I’m eager to make more bras with foam. And to try fold over elastics! On the pink bra, is it just the elastics that holds the ring?

    1. Hi Emelie! Thanks! On the pink bra I added a little bit of stay-tape (you can use twill tape or some other non-stretch tape) to the underarm area and for the part holding the rings. You can do that anywhere you want a little more support. I also did that for the straps on the bralette where the fold over continues up from the neckline and underarm. It’s so easy to conceal in the fold over as well!

  7. Hi Erin, I love your post – so clear and helpful! I hope you do lots more tutorials like this over on your blog 🙂

  8. Hello, Erin, thank you for your good explications! I have got a question: can this foam and the usual fold over elastic be used for swimwear or has it to be special ones?

    1. Hi Sasa! Yes this foam can be used in swimwear it is quite chlorine resistant (make sure whichever one you purchase is chlorine resistant too). The elastic is also good for swimwear! The stuff I used is nylon spandex, which is the same components as swimwear fabric so it should be fine. I did make a bathing suit using the black fold over and wore it in a brutal hot tub (it bleached out my swimwear fabric too!) and the elastic faded a bit. – but really I don’t know how anything should be expected to stand up to the chemical soup in a hot-tub. So the long and short of it is- yes fold over elastic should be fine to put in a bathing suit- but nothing can really withstand a hot-tub.

  9. This is great! I really admire your bra and swimsuit making skills. I am looking at the foam on Bra Makers Supply and she has Poly Laminate and then Swim cup foam for half the price. Which one do you recommend? I have not yet tried a bra, only swimsuits.

    1. Thanks Ashley! I actually use the “pre-finished foam padding” on her site- it’s the one that comes in lots of colours, I find that both the poly laminate and the swim cup foam are much more plastic in feel- they aren’t as nice against the skin. It’s the same price as the polylaminate, and also has similar properties- the swim cup foam has small ridges and is a bit stretcher. Hope that helps!

  10. I have a silly question, I’ve been searching for the foam padding and came across something called “t-shirt backed sew foam”, would that be the same type of foam or something completely wrong?

    1. Hey! Sorry I didn’t notice this comment. I’m not sure about the foam, it sounds nice, but I would always recommend getting a sample before you commit if you’re buying a large amount!

  11. Hi, Just getting ready to try using the cut and sew foam. Wondering if you have to pay attention to grain or DOGS when cutting the foam? What about where you sew it to the frame…any special considerations given the thickness of the foam?

  12. Thanks so much for this post! I have never seen this foam before. I must go and look for it. I’m large busted and the store bought bra inserts for sewing are about 3 sizes too small for my girls. I would really like to make a sundress or two, but just haven’t done it because of this issue. Do you think I could take one of my current bras and copy the pattern to get the correct cup size? Just wondering how to customize this to my shape. Tips?

  13. This is amazing. This is the first thing I’ve seen about making bras that made sense to me. Thank you my sister is a plus sized woman and can’t find a bra that fits her. So I want to try to make her one. Buying my very first sewing machine tomorrow. Thank you so much and I will be following your blog.

  14. Have you ever tired using this foam on swimwear? For example on an unstructured triangle top? Would you just cut the shape and insert it?

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