Most people just sandwich the raw edges of their garment in the bias tape and sew straight through all the layers. SO MANY tutorials do novices sewers a major disservice by claiming this is the "right" way to put on bias tape. It works, but I wouldn't call it "right." This method is easy, and fast, but does not look particularly attractive, and essentially wastes much of the functionality of the bias tape.
If double-fold bias tape is put on correctly, no stitches are ever visible. Double fold bias tape has three folds in it - a center fold, and two folds on either side where the edges are folded in to the center line. One of these folds is very slightly offset, so that when the bias tape is all folded up, one-half is slightly wider than the other.
1. Take note of which half of the bias tape is wider. Open this side of the bias tape up so you are looking at the inside of the folds.
2. Working on the front of your garment (outside surface), align the raw edge of this half of the bias tape with the raw edge of the right side of your garment, and pin in place.
3. Sew on the bias tape - you will be sewing through only ONE layer of the bias tape, and underneath that, will be the front of your garment, followed by whatever interfacing/lining layers are beneath that. Your stitches should be ever-so-slightly on the raw-edge side of the bias tape fold.
4. Once this half of the bias tape has been sewn in place, allow it to refold itself along the fold you just sewed next to. The center fold of the bias tape will naturally fold directly over the raw edges of your garment, and the other (narrower) half of the bias tape will now be on the backside (or interior) of the garment.
5. Using a needle and thread, HAND SEW the narrow half of the bias tape in place by using small stitches to tack the fold to the machine-sewn seam made in step 3.
When you are done, the bias tape will be securely in place, all garment raw edges will be covered, and the seams used to do it will be completely hidden.
I don't have the time to do it right now, but when I get back from vacation, I can add some pictures to better illustrate the process.
Pictures and tutorials from my costuming portfolio at Syagria's Cosplay Site!
Star Trek Original Series Uniform!
Original Creation for AB13
Most Recent Con:
PAX East, Anime Boston 2013