In this video I troubleshoot the problems and show you how to sew outdoor fabrics using a rolled hem foot, including challenging fabrics, such as very lightweight (1 oz Hyper D ripstop nylon, 0.66 membrane taffeta) and waterproof (1.1 oz silpoly), using a rolled hem foot.
You can put a rolled hem on your tarps, underquilt protectors, and other outdoor fabric projects without needing a thousand pins.
You can roll a hem on fabric cut with a catenary curve, or on the bias of the fabric.
The trick is to use a strip of tissue paper beneath the fabric to provide traction between the feed dogs and the fabric, and to pre-fold and guide the fabric into the foot while sewing. If sewing a straight seam (not a zig-zag), the tissue paper will easily tear away when you are done sewing, and your rolled hem seam will be straight and true.
If you are new to the rolled hem foot, I suggest you practice your skills on scrap fabric first.