“OK, you say….I've got the project…I’ve chosen my fabrics… NOW what about thread?”
Matching colors to fabric that’s simple enough. But which thread is right for the project?
ALL PURPOSE (cotton-covered polyester core) - this thread is not what it seems. While it proclaims to be all purpose it is not suitable for every project. It is most commonly used because it is polyester and is strong, and stretches. The cotton is smooth and therefore sews easier. This thread can be used on natural or synthetic fabrics as well as knits and wovens. It is generally good for either hand stitching or machine sewing.
UPHOLSTERY, BUTTON OR CRAFT - if you’re projects are of the heavy duty type then you’ll need these threads. They are the heaviest and strongest and have a special glazed finish that stops abrasion tangling. Need to tuft buttons on a cushion? Finish an upholstery project, attach trim or braid to rugs? Then this is the thread for you!
RAYON - Does your project call for rayon? Well, if you’re doing decorative or machine-embroidery then this thread is a very good option. Rayon has a shiny texture that causes it to look like silk. Rayon comes in a variety of colors: solids as well as variegated. Read the manufactures directions for special care of the threads and you will need to use a 40 or 30 weight in the needle. However, you will need to use a finer weight in the bobbin when machine embroidering or for other decorative effects.
SILK - This is the strongest and the most brilliant. However, they are among the more expensive because it is made from long, continuous fibers that has vibrant sheen. It stretches and so is a good choice for garment construction and tailoring. Use 50-weight for all-purpose machine sewing and 100 weight for applique’ and heirloom sewing. If you want to use silk for top stitching, quilting, or embroidery then you’ll want to use 30-weight silk.
METALLIC - Your choices here are just about unlimited. This thread glistens and is used (for the most part) in decorative stitching. And because it comes in so many colors (solids and variegated) it makes a good choice for satin stitches or machine quilting. When used in overlock (sergers) sewing it can be used in the loopers and for normal sewing machines this thread can be used in the needles. . Metallic threads shred, splinter and ravel so it is a good choice for bobbin work as it doesn’t have to pass through the needle.
100% COTTON - At one time this thread was the only thread available for the home-sewing project. With the improvement in durability and versatility of other threads it has wained in popularity. Best results are achieved with this thread when hand or machine sewing cotton and linen fabrics. 100% cotton mercerized thread is smooth, light, and colorfast. It does have a slight stretch but it ideal for quilting on cotton fabrics.
Sources: Labels from end caps of thread spools
Simply Creative Sewing Magazine 2003 Issue