Gray tee-shirt bra.
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A grey teeshirt bra and panties

One thing that prevented me from getting into bra-making earlier was that I thought you couldn’t sew a proper teeshirt bra at home. However, I was so wrong! Now that I have become pretty comfortable in sewing my own bras I think I could share some tips on how to make a teeshirt bra with seamless cups.

I use the Pin-up girls Amanda/Alyssa pattern as a basis but I use methods that I have learned on Make Bra online course, some features that I have seen in RTW bras and some that I have come up myself.

Selecting the right foam cup

How to choose the right size foam cup? The foam cups are numbered so, that the number corresponds to the band size in which the cup is a B cup. Got it? This comes from the fact that the cup size depends on the band sizes. So 80A (36B) has the same cup as 75B (34B) and 70C (32C). These are called sister sizes. So look at a sister sizes chart and find your sister size that corresponds to the B-cup and marking down the B-cup band size. That number is your cup number. Usually, those are given in inches so that the 70 cm band corresponds to the 32″ and so on.

You can also double check the right size by taking a underwire bra that fits you and comparing the underwire size to the underwire chart. B-wear has printable pdf-charts for all the usual underwires which makes comparison pretty easy. The underwires are numbered similarly to the bra cups but different cup shapes require different underwire shapes. However, if you are not sure, you can ask which foam cup would suit the underwire that fits you.

Covering the foam cups

You need a lightweight 4-way-stretch lycra. Cut out a chunk of fabric that is about 10 cm (4″) bigger than your foam cup dimensions. Pin the fabric from the top and bottom of the cup and then start pinning the edges. At the beginning you’ll end up having a big wrinkle. Continue moving the pins and stretching the fabric gently. Beware the cup collapse! If you pull too much the foam cup will not be able to keep its shape and you will have a permanent bump that doesn’t go away. When you are done, you should have something like this:

Stretching the fabric onto the foam cup to make a seamless teeshirt bra cup.

Mark down the upper edge of the cup and take your fabric out. Cut the marked edge leaving about 6 mm seam allowance:

Marking the cup top edge.

Pin the fabric on the wrong side of the cup’s upper edge. The right side of the fabric will go against the cup:

Pinning the cup cover fabric to the wrong side of the cup.

Sew the fabric on to the cup from the foam side very close to the cup edge. Be slow and careful with your pins. I use very thin pins so the likelihood of me hitting a pin is very small.

Sewing the cup cover fabric onto the top of the cup.

Trim the seam allowances of the cup cover fabric to remove all the possible causes for lumps and bumps. Then flip the fabric over the cup edge. Pin and zigzag the other edges of the cup.

Fastening the other edges of the cup cover.

Trim the extra fabric and your seamless teeshirt cup is done!

The covered cup is finished.

Want to add some lace onto the cup? That’s easy. Just take a piece of stretch lace and lay it onto the cup:

Adding the lace.

Trim the lace:

Pinning the lace onto the bra cup.

Now zigzag the lace edges and hand-stitch the upper edge onto the cup cover fabric.

Fabric covered straps

Normally I just use strap elastic to make my straps. My boobs don’t need the support from the fabric straps so I don’t use them. However, this time I wanted the straps to match my cup fabric. I also needed a way to finish the cup sides and this method that I explain below does both of those things. I have used a similar kind of a method before and I don’t remember where I got it from or even if I invented it as I was sewing the bra. However, this time I didn’t have a scalloped strap elastic so I covered the whole strap.

First, I made a long tube part of which was left open:

Making a fabric tube for the bra straps.

Turn the tube around and thread your strap through. The width of the tube should match your strap width:

Covering the bra straps.

Sew the strap onto the cup edge:

Fastening the strap elastic onto the cup.

You’ll have to make a tiny clip to the seam allowance at the top edge of the cup to be able to fold the ends of the strip around the cup edge. Pin in place.

Pinning the cup side binding.

It pays to baste the binding in place before zigzagging it in place. Then finish the strap attachment by enforcing the strap attachment from the top. I admit I should have stayed a bit farther away from the edge since I stretched the fabric a bit. However, I wasn’t too bothered about it so I left it in place.

The finished cup and strap insertion.

The rest of my teeshirt bra

What about the rest of the bra? I didn’t take any more pictures on how I sewed the band. I did leave out the side seams so my band is made of one piece of lycra. To keep the cups in place, I have a stabilizer fabric in the middle on the wrong side. This is a method that I learned from Make Bra. I used a pair of underwires that I took from an old bra that I threw away. A tiny bit of lace decorates the front of the band:

The finished teeshirt bra.

Here you can see the top edge of the cup from the wrong side:

Teeshirt bra cup detail.

This is the teeshirt bra from the wrong side:

My teeshirt bra from the back.

Matching lace panties

I am determined to make matching sets. This time I made three pairs of panties. All of them are based on the free Megan Nielsen Acacia underwear pattern. Two pairs had lace at the sides of the front piece:

Acacia underwear panties with some lace inserted.

I cut out the lycra from behind the lace:

The lace insertion detail. The lycra fabric has been trimmed from behind the lace.

For the third pair, I decided to use the lace at the back piece. I also had to switch into a different elastic since I run out of the one I used in the other two pairs.

The third pair of panties.

This is how the panty looks from behind. As you can see, I constructed the back piece out of two symmetric strips of lace with a seam at the centre back. I added a small piece of lycra to cover the little piece at the top.

The lace back of panties.

Now I have this lovely set with a teeshirt bra and three pairs of matching panties:

My set of a grey teeshirt bra and three pairs of panties.
The finished set of bra and three pairs of panties.

I hope you found this post useful. I can warmly recommend making your own underwear! If you are interested in learning more about lace and bra making I recommend online courses on Bluprint:

Sewing Bras: Foam, Lace & Beyond

from: Bluprint

I have actually taken the whole year subscription with the included forever courses that I can go back to whenever I want. Click the banner below to get the offer that is available through 17th of February:

Get 12 Free Own Forever Classes and a year of Bluprint for only $69.99 at through 2/17/19.

Thank you for reading! Subscribe and come back soon to read more about my adventures in sewing and crafting!


I am a mother of two. I sew, knit and create and blog about it.


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