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Sewing a wedding dress: Ultimate Underwires and Boning

May 20, 2015

So this is what everyone wants to know, right? How do you sew a strapless dress that stays up? I don’t recall Grace Kelly or Audrey Hepburn persistently yanking gowns from the neckline. There are lots of little tips and tricks for achieving this but it’s no secret that boning does most of the work. Let me update you about how I put the structure into the strapless corselet which formed the foundation of my wedding dress, drafted and constructed in this post.

I inserted underwires in the underbust seams of my toile and spiral steel boning into all other seams. I carefully unpicked the underwire casings from an old bra (something old?) and the spiral steel was sourced from aussiecorsetsupplies. If you’re contemplating a strapless dress with this sort of construction I want to reassure you that you CAN do it, I cannot overstate my level of confusion at the beginning of this process and my dress turned out just great.

The first tip is to catch stitch every single seam allowance. You can see this in the pictures throughout this post. Catch stitching helps control bulk through the intersection of seams and ensures you don’t create puckers by folding up your seam allowances with your presser foot, believe me you have other things to worry about when this thing is under the machine.

Steel vs Plastic

I decided early on to follow my DIY couture heroes Gertie, Laura Mae and Mel and use spiral steel instead of plastic boning. It is a little trickier to work with but I quite enjoyed the challenge, and the end result is fantastic: light, strong and two-way-flexible.

Cutting and tipping

This is the not fun part of working with spiral steel, but once you get the hang of it you’ll be producing tipped bones for all your friends and neighbours! There are some great tutorials on how to do this but I needed serious hand-holding to work this out, so have some details instructions below.

You need to cut your bones at least half an inch shorter than the seam into which you’re inserting it. This is to minimise the chance that the bone rips apart your garment and starts poking out when its under stress – even with the smooth tips in place the strength of the steel will get through most fabrics.

wedding dress boning

You’ll need two tools in order to cut and tip successfully. Some wire cutters (blue) and needle nose pliers (yellow). I found that the cheapest, biggest set of wire cutters was much more effective than more expensive, smaller cutters. They cost about $10.

wedding dress boning

You might think that with big cutters like these you could just indiscriminately chomp away at your boning and successfully cut through it – If you enjoy experiencing failure and disappointment you might like to give this a go because it just cannot be done. But that doesn’t mean you can’t cut this stuff! The blue arrows above point to the little spirals that jut out laterally from the boning. This is the only point where you can snip successfully. Just get your cutters in there and snip the individual wires on each side, the boning will then be in two pieces.

Now get out your needle nose pliers, as I only have two hands I have used my artistic talents:

wedding dress boning

Sit your tip at the end of the bone and squeeze it “side to side” (as above) with your pliers. Do not be scared to really go for it here, it needs to be on snugly.

Squeezing the tip in this way will create a bit of a problem, however:

wedding dress boning

Can you see the little pointy bit that has emerged? This is your enemy. This little villain will cause havoc on your boning channel as you’re inserting the bones, and if you have to remove them for any reason it will snag and rip a hole in it. So to prevent this from happening turn the bone over and squeeze it “front to back”:

wedding dress boning

Use your pliers to squish the pointy bit flat.

Note: Doing this will probably loosen the tip substantially, so I advise squeezing the tip in both directions several times until 1) the bone is secure and 2) there is minimal pointy business on the top of the tip.

Boning placement

wedding dress boning

It is difficult to establish where exactly you to put the bones, there are no hard and fast rules so I solved this problem by putting it everywhere ! I had boning in every seam, plus four diagonal bones (two in the side panels and two in the back). This provided an excellent degree of support for my bust and helped maintain good posture. The excellent fit of the pattern coupled with the flexibility of spiral steel meant that on the day I did not feel constricted or stiff, I loved every minute in my dress and found it surprisingly light and comfortable in the end.

This threads tutorial is excellent and contains some quite unusual boning placement options for non-bridal garments.

Boning channels

Ok so knowing where to put the bones is a good start, but you need to create a nice little environment for them to live in. Your options are:

  1. Construct the corselet in such a way as to create channels between layers (Gertie does hers this way here)
  2. Utilise the seam allowance to make a channel (carefully trim one side, fold the other side over and top stitch)
  3. Produce channels and stitch them in

Option 1 was sadly unavailable to me. I did underline my corselet with organza but to use it for boning channels would have meant constructing the two layers separately thus defeating the intention of underlining.   Option 2 was also unavailable as the curvature of the seams meant they had to be clipped like crazy to ensure they lay flat. Ergo, I started thinking about how to make some channels.


I spent a fun couple of hours stitching lines into  a double layer of silk organza as above. Give it a good press to ensure they are on grain ! This really counts as any torsion in your channels is going to allow that boning to bust out of the channel.

As my boning was 7mm wide I sewed channels 10mm wide to allow a bit of movement. Then I got out the pinking shears and cut them all up.



Then just stitch along the existing stitches to put them onto your garment.

wedding dress boning

Some pictures from my toile might help you get them in successfully. I really advise against putting the bones in until the last possible moment, getting your garment under the machine becomes difficult very quickly once the bones are inserted.

Remember the nasty pointy bit that invariably shows up when you tip your bones? I found the best defence was the strange pointy metal bit on my nail clippers. I used this to open the channel slightly at the bottom, allowing the tip to slide in without snagging the organza. You’re welcome!

wedding dress boning

wedding dress boning

Voila! Finished boning inside its channel with lovely catched-stitched seam allowances underneath. The seam allowance actually works as a double insurance policy against bones poking out, so I really recommend this method.


Underwires are intimidating but it is no more complicated than adding a boning channel, just a thick, fuzzy, curved boing channel.

wedding dress underwires

Once your underbust seam is nicely pressed and catch stitched flat it quite simple to pin the bottom of the casing along the seam and stitch in the ditch to secure it.

I marked the centre of the underwire channel with blue texta and matched it to the corresponding centre-underbust-seam.

Then stitch the top edge of the casing to create a top-stiching effect on the right side.

  • Unless you are crazy and doing this in fashion fabric it does not matter if your top stitching is terrible (mine was). Just get the thing in there and move on.
  • I advise leaving this until after the boning channels are in, as  if you’re boning seams that abut the underbust it is tricky to get a nice junction between the boning and the underwires if you put the underwire casings in first.
  • Don’t forget to stitch the ends of the channels shut!

wedding dress underwires


Hooray, it’s in!

corselet toile fitting 2Bridal Corselet Toile tutorial

So this was the finished toile with bones, underwires and all. Make sure you’re not going to loose your dignity when raising your arms! It felt like a million dollars so I moved on to my coutil, I will save the vagaries of working with coutil for another post.

Please leave me a comment if you found this post useful, want to say hello or have any thoughts or questions about strapless dress support.

Some other resources you might find useful:

Catina’s epic strapless bodice sewalong  

Laura Mae’s “Underpinnings” 

Mel’s Marfy 2630 Bustier

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