My teacher in Atlanta said to always use a 1/4 inch seam allowance for draping, but I found out it depends.
Mrs. Carter, my design instructor, was very firm about that specific measurement for all our muslin work. When I tried to drape a bias-cut skirt last month, that tight allowance just bunched up the fabric and ruined the line. I switched to a 3/8 inch allowance for that project and the drape fell perfectly. Has anyone else run into a 'rule' that only works for certain fabrics or garments?
That's interesting because a quarter inch is basically the standard for flat pattern making, not draping. Draping needs more flexibility. A bias cut like you did absolutely needs a bigger seam allowance, the fabric needs room to move. Even with a straight grain, a thicker wool would fight a tiny seam allowance. Teachers sometimes give one rule to keep things simple for beginners.
Yeah, the whole quarter inch thing falls apart with lace or mesh too. Those fabrics can't handle a tight seam. You almost need a half inch just to stop it from chewing up the edge in the machine. The rule really only works for basic, stable muslin.
My first sewing teacher in Miami was the same way, she acted like a quarter inch was a holy number. I mean, I get it for a basic woven cotton, but I tried it on a silk charmeuse slip dress and it was a total mess. The fabric just kept slipping out of the seam. I had to go up to a half inch just to get it to stay put long enough to baste. It really does depend on what you're working with.