From Fatimas blog http://moldesedicasmoda.blogspot.com
This lady is a legend to me at least, she posts two patterns a day and shares tips like this. For all those people who struggle with rolled hems on lightweight fabrics, she has this tip, which is a gem, in its simplicity.
I would not normally copy a whole post, but I know links to a post that are not in English put some English speakers off and this was such a little gem, I thought it was worth it.
Translation from google
STEP BY STEP DOUBLE SHEATH
Fold the hem and sew into the edge with the point size 2.5 or 3.
With scissors trim the excess fabric
tissue than doubled, with the point that sewed.
Fold back inside and sew on top of the previous
point. sewing line
The interior is two points and the outside to only one. From the inside you see 2 sewing lines, but from the outside you will see only one. This shot is excellent for many jobs because the finish is always with a beautiful touch. It is widely used in haute couture, for those who have to do the sewing hems, or who uses the old machines.
Thank you Fatima for this tip
Check out her blogs, you will not regret it, and just use google translate, if you need to know what she is saying. I just look at the pictures sometimes. If google needs to be told what language, Fatima writes in Portuguese.