Sometimes I work with lycra that is thin and has a lot of stretch. Not a good fabric for my bra’s, as I need support both in the cups and the band. Often the nice lycra’s (and besides beautiful lace I do love a lycra with a beautiful print) are too thin to use as they are. The solution: interfacing. The downside of using an interfacing: risk of shifting layers with pleats as result. This is what happened in the center of this bra that I made a couple of years ago, look at the bottom of the bridge:
This is how I tackle this issue now (and I’m sure I’ve written about this before, can’t find the post however):
Depending on the result I want I use an interfacing which has no stretch at all or that has a little stretch (but less than the lycra). The bridge is always interfaced with an interfacing without stretch. I’ve used the lycra of this example for an all-lycra bra without lace which is not finished yet, and used an interfacing with a bit of stretch for both the cups and the band in a very light skin-tone color.
For demonstration purpose I used a black, non stretch interfacing in this post.
Cut the pattern pieces in both interfacing and lycra, with seam allowances of course.
I’ve pinned the two layers together to show both pieces are the same size.
Stretch and pin the lycra so that all seams are beyond the interfacing pieces. It depends on the amount of stretch how munch you do this. With this thin lycra it was 2 to 3 millimeters on all sides.
When you lay it on a flat surface, the lycra will pull on the interfacing and it will not lay flat.
Zigzag the layers together within the seams allowance!
Cut off the edge of the lycra.
The pattern piece has its original size again but looks a bit weird. It’s no problem at all to work with though.
When sewn together and worn, the lycra will lay smoothly over the interfacing without any pleats.
When I started making bra’s I used a fusible interfacing for the under cups. This was a special interfacing that I can’t find easily any more, so most of the time I use this method for the undercups.