The two names can be confusing. Crin is the term everyone uses for horsehair, except here in the U.S. In the U.S. we call this finely woven synthetic flat braiding horsehair. Originally, it was made from real horse mane and tail hair. But that became costly and as the demand grew new fibers were taken on. When I started in the business it was made of nylon, and I still prefer that material but as far as I know, no mill is making the horsehair/crin from nylon now. Instead it is made from a polyester fiber.
Crinoline is a sized cotton foundation that is usually milled in a 39 inch wide gauze material. In this case, as a bias tape, it has been cut into one-inch bias strips to use on edges of hats, or inside crowns on two piece hats to help strengthen the joining and so on. It has some give because of being cut on the bias. Besides its use as an inner base you will also find it used in trim work as a backing or foundation. I enjoy creating ribbonwork hat trims and handmade floral trims which I back with crinoline. This holds the piece together on one base and also gives the option of tacking it to the hat, dress or lapel with easy removal by a few snips of thread. (Note: production of this product has become very limited.) Both crin/horsehair and crinoline are sold by the yard or bolt.
What to do with Crin?
Whereas crinoline, the sized cotton, has only a few basic uses and two colors, the sky is the limit with horsehair. HORSEHAIR (CRIN) is a finely woven, slippery fabric, available in 1/2-inch to 6-inch widths and also tubular form that comes in several diameters. It is more difficult to work with than veiling and other standard trims. There are many colors available and a wide variety of styles, such as standard plain, pleated or chenille dotted along with a lurex zigzag and other specialty pattern weaves. The standard crin/horsehair has a cotton thread running along one edge in most widths which allows for easy gathering of the braid. Horsehair that is less than two-inches wide generally does not have this thread. A gathering thread can easily be added by running along an edge with a long machine stitch or by hand using a long basting type stitch. Horsehair/Crin has many uses in the fashion world. It can be used to fashion the hat frame, or to be the dash of trim on the hat. It is frequently attached to the hem of gowns to help hold the skirt away from the body. Recently I saw it as an underlay at the neck and a wide edging to the skirt of a party dress. There is a stiff version of horsehair that comes only in white and black. It’s basic use is in drapery backing.