I used invisable elastic for lingerie and for stabilase the shoulder seams on knits but it took me many years to find out that the Framilon that so often are mentioned in Ottobres patterna where the same thing...and then it tock me some more years to decide to try it out and now I´m in love! It´s simple to sew, the result is great and you can get it almost everywhere even in Sweden...
I use the thin one that I guess is about 6 mm.
First you have to sew it to the part that is not going to be garthered and I prefer to do this with the 3-sted zig zag that propably has a totally different name in english. I sew it to the right side of the garment and just outside there the seam is going to be.
Then I pin the part that are going to be garthered to it right sides together and devide the ease with pins so the gartheres will be evenly over the area.
Now I sew the parts together...I´m not a skilled serger so I prefer doing this at first with my regular machine with slightly larger stitches like 3,5 mm.
When I came to the garthering part I stretch the fabric where the framilon is and continue sewing the entire seam
This is how it looks finished and the framilon is inside
so when I finally serge it it will be inside the seam but still doing the job as stabilizer.
And this is the finished top, the Violet Rose again in a grey rayon jersey for the yoke and som kind of ribbed knit of unknown fiber content for body and sleeves. Both fabrics are from Stof och Stil.