Today, I’m taking you behind the scenes of our new Symmes Strapless Bra sewing pattern.

Hold on tight—it’s a bit of an emotional rollercoaster!

The Symmes Strapless Bra sewing pattern is built for real support in sizes 28C-54J. No slipping, no digging—just a secure fit that’s more comfortable than any strapless bra you’ll find in stores. And it’s a total game-changer for your wardrobe.

I’ll be honest, I really didn’t think we were going to be able to design a strapless bra sewing pattern that delivered on the three key non-negotiable aspects: great support, great shape and comfort. Why? Well I’d literally never ever tried on a bra like that before! And I wondered if physics might just be winning the day against my 38Is.

Luckily, my team was there to remind me that I *had* previously said that about making any kind of bra (and then… the Willowdale was born) and subsequently about making a wireless bra… (lo and behold, the Loftus!). So I begrudgingly said: Ok fine, let’s TRY. We won’t announce it, and then if it all fails, then we’ll just scrap it and move on. And indeed, the first attempts? Woeful! (Read on for more on that and some incriminating pics). But in the end…

THE MAGNIFICENT SYMMES BRA WAS BORN.

It was SUCH a journey from beginning to end that I thought I’d share with you a little about the development process, including some photos which, let’s just say… were not intended for marketing purposes. Ha! But I think they’re very illuminating, so enjoy seeing what non-photoshoot-shots, taken in my basement, in overhead lighting look like ;D

Be prepared: all these samples look very, very rough. For bras, we have a very iterative approach where we start with a pattern from the drafter, and then Jen and I work ourselves for as long as we can to improve and optimize the fit (partly because all our work with the drafter is remote and bra development is a very hands-on exercise), which often leads to some Frankenstein-level muslins. Then once we’ve figured out a possible design route, we do another round with the drafter, and so on and so forth.

Needless to say, we are very capable of making bras that look a lot better than these! But the process is mostly working out the physics—aesthetics come later.

Step 1: Sad puppies

The first step out of the gate was “simply” (it’s not simple!) translating our existing Willowdale Bra into a strapless format, on our first bra fit size, a 38I.

Oh, how we laughed.

In this pic, the left hand side is what we started with—and in fact, it was even a little worse than this as you can see the pin at the top of the cup was improving matters slightly. I cannot lie, at this point I literally said to Jen, “Maybe we give up, I don’t know if this is going to work.”

Jen is made of sterner stuff than I, so we persisted.

We did a bit more research on existing ready-to-wear strapless bras and noticed that almost all of them were made from moulded foam cups. Now, I’m sure most of you are aware that big boobs laugh at “pre-made” foam cups which are made for only the most daintily endowed of folks. But cut and sew foam? Now that’s something we could do.

First incredibly rough attempt was simply re-cutting the Willowdale-based pieces in foam and throwing them in there, as you can see on the right hand side of the picture above… The result? Better! But good? Absolutely not.

But trending in the right direction.

Step 2: Bring on the foam

Clearly, the Willowdale three-part cup wasn’t going to hack it. So the next step was trying a vertically seamed approach using the foam again (sewing it together with seam allowances, which you wouldn’t actually do with “real” foam). As you can see, we did one cup at a time so we could compare it to the previous cup.

And behold, a massive improvement! Unlike the sadly collapsing cups previously, the foam stood way more upright, and this is the point at which I thought ,”Huh, maybe we *can* make this thing work.”

Step 3: Shaping and boning, oh my

With our rough changes in hand, we worked with the pattern drafter to make the next version, and also tweaked the relative proportions of the panels to give a better shape.  On this sample we also properly added boning, including the middle gore.

Not TOO bad, but as you can see, the seams were collapsing especially in the middle part. And the side view… eek! Where did the boobs go?!

So we decided to add boning to every seam line and see what happened.

Step 4: Houston we have lift-off

SO CLOSE!

We added the boning in the cups, as well as some strategically angled pieces around the back band, and finally had both lift and decent shaping. But the proportions just looked slightly off on the first attempt (left side on the picture above), somehow making my ample bosom look even ampler.

So we tried simply trimming it down and taking a little more out of the top of the cup as it was gaping (again not obvious in this photo, but obvious in real life).

The side view was much improved from before, too (albeit needed some more upper cup shaping), and the back was also fitting well and not collapsing.

Step 5: First fit sample: defying gravity

After another round with the drafter to implement our changes, we finally had a winning prototype for the 38I! Bear in mind that my boobs are different sizes—so on the right side of the pic is my 38I boob (lol) and the other side is slightly wider/bigger, which is why it doesn’t look QUITE so good. Obviously for development we need to keep things symmetrical but I could easily make adjustments to the right cup to fit. We did also raise the side of the cup just a smidge to cover the boob crease you can see from the side.

Step 6: People other than Jenny need to be able to wear this bra

Alas it would be easy if it could end there… but one-size patterns are not the Cashmerette way. We knew we needed to test both smaller and bigger—but bigger would be more of a challenge because ultimately a strapless bra sewing pattern for big boobs is all about managing the weight of larger breasts, so we decided to start there.

As you can see, our first effort at a “graded up” 46J was… suboptimal (WAH WAH).

Step 7: Grading on up

A new grading approach was needed! The back band got a lot wider (and is now very variable depending on the breast volume) and various other changes were made including a lot more boning to both the cups and band. And behold: once again, nailed it!

Step 8: Ready for your mammogram?

The “simply graded down” version had you all prepared to put on that gown and get your annual scan.

Oh, how we laughed.

Step 9: A big sigh of relief

Again, back to the grading drawing board, with much more upper cup volume, and we’re good (we still had a little bit of tightness in the upper cup, but that was sorted out).

Step 10: JUMP UP AND DOWN

Well, knock me down with a feather but we did it. A strapless bra sewing pattern for big boobs with

1. SUPPORT
2. A NICE SHAPE
3. DOESN’T PHYSICALLY HURT TO WEAR (nay, is pretty comfortable)

Will I learn from this that we can tackle things which seem super intimidating? Maybe, maybe not. But what I CAN tell you is that a whole new world of Cashmerette patterns just opened up now that we can make strapless garments… watch this space!

Ready to sew your very own well-fitting strapless bra?