This handy little trick allows you to “tack down” 1/2″ edging into straight lines without bunching, folding and did I mention straight. The glue holds everything in place while it gets sewn down. You can use pins to help the holding power. I use the 1/4″ so that I have a clean, clear edge for stitching down. Sometimes it is hard to get a needle (hand or machine) through the glue. I am not substituting sewing here, just using a product to help keep those nice even straight lines. On the Bear Dress, I am doing a double diagonal pattern and machine zig zag stitching the edging down (this is a respectable 1 ft dress, not an A & S entry).
In period they used chalk, pins, time and probably quite a bit of cursing, un-doing and re-doing.