Sometimes, you just want to finish an edge really really fast – you don’t care if it looks pretty up close. (Like, say, you’re working on a show where everyone seems to wear a veil that the audience can see through, but the characters mysteriously cannot… Not that that ever happens.) The zig-zag stitch on your sewing machine is the poor man’s serger…
Seam Allowance Required: 0″
You might be having sort of a “Well, duh” response right now. I admit this is less than overwhelming, but it does have some important applications. First off, this actually is the best way to finish a veil in a big bad hurry. It’s also a good idea to run a zig-zag over the edge of fabric you plan to gather – it keeps the seam allowance from disintegrating into a thready mess as you’re pulling the gathers down.
Why not do both at once? Because it will add bulk and may make the seam mis-behave in strange and unpredictable ways.