How to choose and cut an underwire ?

How to choose and cut an underwire ?

You've fallen for the bra Cosmo or Smoothie, and you would like to integrate underwires, but you don't know which shape to choose?

No problem ! We have prepared a PDF file containing the "ideal" underwire drawings for each of these models, to be printed in real size.

This way, you just have to compare your wire to the drawing, and check that they are similar 😉

Click on the pictures to download the PDF files:

XS -> 5XL
XS -> 3XL

Now you have found some frames, but they are too long ... Wondering how to cut a frame so that it perfectly matches your model, but you don't know how to go about it?

We tested different solutions, with easy-to-find tools / supplies, so we could give you a helping hand 😉

Are you ready ? Let's go !

  1. How to cut an underwire ?
  2. Finishing the edge

1. How to cut an underwire ?

NB: Think about protecting your face when cutting, to prevent small wires particles does not jump to the eyes!

To start, draw the line on the underwire, to cut it to the correct length.

Use a side-cutting pliers / a cutting wire to cut the underwire at this line, holding the underwire firmly with the other hand. If necessary, do not hesitate to rotate the end of the underwire from left to right to facilitate cutting.


Here you go, your frame is the right length, but the edge is very sharp and risks piercing the underwire channel...
To limit this, use a steel file, or a sheet of sandpaper, to round off sharp edges.


2. Finishing the edge

Now that you have filed the end, you have to cover it with a hard material, which will hold over time and over washings.

Here are the different possibilities that we tested (in application, and washing at 30 ° C):

1/ With nail polish:

Immerse the end of your underwire in a pot of nail polish, let it dry upside down.

Repeat the same operation 3 times to apply a good thickness of nail polish.

This solution is simple and can be washed at 30 °. Depending on the texture, it may appens that the nail polish is rather "flexible" and does not necessarily last long in the wash cycles.


2/ With a glue gun:

Pour a "block" of hot glue using a gun, over a piece of sheet, or a surface that does not fear heat.

When the glue is still a little hot / lukewarm, rotate the end of the frame on the sheet of paper so that the glue covers the entire end of the edge. Let dry and harden.

Once the glue has hardened, check that the end remains firmly attached to the frame if force is exerted on it. If the glue tip comes off, it will not hold up when washing, we therefore advise you to repeat the previous operation until the end fits completely to the underwire.


3 / With electrician's tape:

Last trick that we have tested and approved: wrap electrician's tape around the edge of the underwire!

The electrician's tape is great because it is strong, sticks well and does not stretch!

Make about 3 turns of scotch tape around the end, and you're done!


You now have a pair of underwire that is the right size and ready to put on your new bra !!

We hope you enjoyed this tutorial and that it inspired you for future creations👙

Do not hesitate to take a look at our Sewing tips and our Blog articles if you want to learn new techniques

And of course, if you have any doubts, don't hesitate to contact us :