Silk, the name it self inspires thoughts of luxury, refinement, and quality. Well, in this case, it definitely lives up to all of the promises its moniker incurs.
Silk threads are among the more expensive thread materials. It is considered one of the most durable threads, and comes in a variety of colors and weights, capable of tackling a variety of sewing projects. Despite this fact, it is predominantly used in delicate garments.
There are two different types of silk thread, filament and spun thread. Filament silk thread is made from the long unbroken silk threads un-wound from the silk worms cocoon in one long piece. Spun silk thread is made from broken cocoons, it is comprised of a bunch of short silk fibers spun together. Filament thread is more expensive than spun thread.
Silk thread is a great choice when you want your stitches to lie flat. It holds color really well, and also has the ability to stretch and regain its shape, making it an option for stretchy fabrics.
The biggest question question I had when it came to silk thread was, how do you wash the stuff? I know every shirt I have that is silk says "dry clean only," Unless I'm making a garment that is going to be exclusively "dry clean only" I want to be able to wash it.
From everything I've read silk thread can be machine laundered and dried on the gentle cycle. Just be sure you don't use bleach, it will severely compromise the integrity and strength of the thread.
I haven't had the need or opportunity to use silk thread, and to be honest, the care still leaves me a little wary. I'm going to save it for sewing something super delicate... Until then I'm going to stick with my cotton and cotton wrapped poly, and a little of the rayon now and then for when I need some sheen...
Hope this was helpful!