Polyester Thread is used for repair of bounce houses and inflatables. Like nylon, polyester is a strong, inexpensive thread with a glossy smooth finish and is used for upholstery, leather, webbing, canvas, an vinyl. Polyester and nylon thread look identical when sewn and have similar strength and thickness. The chief differences are the way these threads respond to bleaches and the outdoors. This means that polyester thread is a better choice for sewing things that are going to be bleached or have prolonged sunlight exposure. For example, nylon thread works fine for a canvas tent that is used for a few outings each year; polyester thread would be better for a canvas hammock that is left outdoors from May to October.