Introduction: Bra

By DrShiny
About: I run Neal's CNC in Hayward, CA, an expert CNC cutting and fabrication service, easily findable by Google search. I'm a founding member of Noisebridge, a hackerspace in San Francisco, and Ace Makerspace (forme…

A bra is a bit more advanced project, but it's not as hard as you might think, and by no means out of the reach of someone with moderate sewing skills. If you're willing to put in a little time on adjusting the pattern, you can end up with a bra that fits you exactly, which all too few commercial ones can do!

Step 1: Tools and Materials

Materials:

  • fabric with at least a side-to-side stretch
  • asymmetrical lingerie elastic for edging
  • strap elastic
  • underwires
  • hooks & eyes
  • a little knit interfacing
  • optionally, stretch lace for decoration
  • optionally, ribbon for decorative bows
  • optionally, plastic hardware for adjusting the straps - but I leave this out b/c I can make the straps the exact right length without need for adjustments!

You can buy underwires in some fabric stores or online, but if you have some old bras that need to be tossed out, reclaim the underwires from them first. Do your best to get an underwire of the correct size (hold it up under your breast and check that it fits snugly but without poking into your breast). They can be bent a little bit but they're actually made of flat metal in a U shape, not round wire, so as to hold shape better.

Step 2: Pattern

Bra patterns do exist for purchase, but I made a pattern from an existing bra. Some of the pieces were traceable, but the cup pieces weren't because of the underwires (I did not want to ruin the original by taking the underwires out). So my pattern was approximate, and I did make a test bra and revise the pattern according to how it fit.

There are four pattern pieces:
  • upper cup
  • lower cup
  • side/back
  • front stay

The important things about the pattern are a) how the cup pieces fit together, b) the lines of stretch, and c) some edges need seam allowances and some do not. Your fabric will almost certainly be stretchier in one direction than in the 90 degree direction; the stretchiest direction should go up and down on the cup pieces and the front stay, but sideways on the side/back pieces. Check out the pictures for the stretch direction markings.

The cup pieces need seam allowance except for the top of the upper cup (you have a couple options there, see the Cups step). The side/back piece only needs seam allowance at the edge that attaches to the cups, as the rest of the edges will be finished with elastic.

I'm not adding the bra pattern here because it will almost certainly not fit you, you'll have to do a bunch of alteration on it anyway and it's really hardly any more work to trace it from an existing bra that you know fits (or know exactly how it could fit better).

Step 3: More on Adjusting the Pattern

I made 1 partial bra and 1 additional complete bra while working out the pattern. The green one in the pic below is totally wearable although the elastic is so curly it looks really odd laid out flat.

There are any number of possible adjustments to make but the most common are these:

  • cup shape, which can be adjusted by changing the curve of the top of the cup lower piece. A small adjustment here goes a long way so change an eighth of an inch at a time, and make sure to smooth out the lines well. If you have to make a lot of change here you'll probably also need to adjust the cup upper as well, making it slightly longer or shorter to accommodate the difference in length of the lower cup edge.
  • center stay. May need to be shorter or longer, depending on how widely placed your breasts are. You may also find that changing the angle of the sides gets you a better fit, either straighter or more flat of a triangle.
  • cup top edge - I found I wanted my bras to be slightly less than full coverage, so I lowered the outside edge of the cup (but not the inside edge). This also meant I had to make the straps longer to make up for it.
  • side/back too short or too long. Make adjustments to this piece in the underarm area.

Step 4: Cut

Cut out the pieces, 2 of each. Remember to lay out the stretch lines as you marked them on the stretchiest direction of fabric. Also I cut the center stay on a fold to eliminate one seam; the stretch line on the stay is up & down not side to side. If you have a very stretchy fabric you might even want to interface the stay or line it with another non-stretchy fabric for stability.

Step 5: Cups

Sew the two cup pieces together along the middle, making sure they are oriented correctly with respect to each other. Topstitch; you may line the back of this seam if you want, like if your fabric is very fine.

Finish the top edge of the cup in any way you want. Here I added a stretch lace piece, but you can also use a piece of lingerie elastic, or if you think ahead you can cut two upper pieces and self-face the edge. In that case you probably want to do the edge seam first and then sew both upper pieces together to the lower piece.

If you put on stretch lace like I did, it will probably be easier to sew it on before sewing the cup seam! You want the lace to be a little smaller than the cup (it stretches after all). Place it with the lace edge along the top edge of the upper cup piece, and sew it on with a small zigzag stitch. Finally trim the original fabric piece out from under the lace -- or leave it if you like the overlay look!

Step 6: Center Stay

Sew the stay together at the top (and bottom if you didn't cut it on a fold) and turn it right side out. Pin it to the inside of the cups, matching the top edges. Sew a little less than a quarter inch seam allowance, as the underwire channels will be the full quarter inch.

Step 7: Sides

With the old bra on, hold up your elastic from the underwire edge around your back to the other cup edge. Pull it to a reasonable tightness. This will give you twice the length of elastic you need for the bottom of the side panels. Pin the end and the middle to get the length for each side, and attach it to the side pieces. (If the elastic isn't an inch or two shorter than the side panel, recheck the elastic measurement and the side piece pattern, as one of them is wrong).

The sewing technique for attaching lingerie elastic is explained in my Panties instructable, in the step about the leg elastic.

Next, sew the sides to the cups, matching top edges, similar to how you sewed the center front stay, a bit less than a quarter inch seam allowance.

Step 8: Underwires

Cut two strips of interfacing, the length of your cups' bottom edge and an inch wide. Fold one in half lengthwise (if you had to use iron-on, make sure the glue is folded inside) and pin it around the bottom edge of a cup, edges out. Place it over the front stay and side piece, leaving a bit of room next to the seam allowance, as in the picture. Stitch the channel down using a quarter inch seam allowance to the edge of the bra cup. The previous stitching lines shouldn't show at all.

Now fold and wrap the underwire channel around to the inside of the bra cup, releasing the stay and the side piece. It should rest a little more than a quarter of an inch inside the cup, and cover all the raw edges. Stitch this in place close to the folded edge of the channel.

Stitch a bar tack across the end of the channel by the center front stay, so the underwires don't come out. Now insert the underwires from the outside edge by just sliding them in the channel you made. The underwires are not symmetrical; there's a shorter end and a longer end although sometimes the difference is small. The longer end goes at the outside edge.

Step 9: Side Elastic and Straps

Determine the correct length of elastic to run from the bra back, around your sides on top of the side piece, up to the top of the cup, by trial and error: first hold a piece so it seems right while wearing your original bra. Write down the length and try sewing it; you can pick it out and adjust if necessary (or if you're working on the practice one you don't need to bother fixing it).

Once the side elastic is on, figure out the strap elastic length. Stitch one end of the strap elastic to each of the remaining back edges without elastic. Now you can pin the bra on yourself and determine how long the straps need to be.

Stitch the strap to the cup, right sides together, where you marked. Cut the elastic if you haven't yet, and fold up the strap so you can stitch the cut end down in a zigzag like in the last picture, to keep it tidy.

I didn't think to do this, but if you have an old bra that's worn out but the straps or strap hardware is still good, you could reuse those parts.

Step 10: Hooks & Eyes

You can use a bra back extender instead which some fabric stores sell, or sew on hooks & eyes yourself. I ended up using a wide single hook & bar, instead of a pair of small hooks & eyes as is usual because I got lazy. But it works fine.

First cover the raw ends with something soft - a scrap of T-shirt fabric works great. I simply cut a square, stitch one end to the right side of the bra ends, fold the sides under, and topstitch them down.

Then just sew the hook & eye down, by hand or by machine, making sure there's enough tail on the eye end that the hook won't scratch your back when you wear it.