You may hear a lot of things about what is the best or the only weight thread to use for free motion or longarm quilting. Personally I don’t think there are any rules. As long as you choose your thread, evaluate your fabric and then choose the appropriate needle for thread-fabric combo AND are willing to tweak your tension settings, you can free motion with almost any thread. Your machine just has to accept it. Some machines can be finicky about weights of threads or even material the thread is made of. Often you can tweak or adjust your method to help use it.
|Quick Guide to Thread/Needle Size
Normally I go to a 50 weight cotton or polyester trilobal thread. I really like threads by Superior Threads, though I am not married to their products. Using a 80/12 Topstitch needle works great with their King Tut, Manifico and Fantastico lines. I have found that as long as I use the same thread in top and bobbin of my machine, I do not have to adjust tension at all.
Note: Superior Threads note on their spools and cones which tell you which size needle is recommended for that particular thread.
If I want a thicker line of thread to show, I will use a 40 weight thread. There are free motion people out there who do not like this thread. But I believe that if the look you want requires a 40 weight go ahead and use it. A 90/14 needle works great.
Thick threads have smaller weight numbers, while bigger needles have bigger numbers. Thread and needle sizes run in opposite directions.
You can even free motion with a 30 weight thread if you want, however, put it in your bobbin of your machine. Thick threads do not work in the top of a domestic sewing machine and will shred or mess up your top tension discs. So in the bobbin it must go. This is often called “bobbin work”. The process is the same, you will just have to work from the back side of your quilt so the heavy thread in the bobbin shows up on the front. If you think your machine could handle a 30 weight thread, you would probably use a 100/16 needle.
Thinner threads than 50 can look really neat. Using silk 100 weight thread for example can have a really nice look. Some of the top free motion people who win shows use silk almost exclusively. I would try a 70/10 needle for this.
Monofilament is also an interesting choice. Typically it is almost colorless. It will really “disappear” into the quilt so the texture is really evident and the thread is almost unnoticeable. There are two types, nylon and polyester. In years past, monofilament, which was made from nylon, got a bad rap because in the early days when it was invented it was very stretchy. So it was difficult to use. You would have to go very slow and have very low tension settings. Nylon also melts at lower temperatures than other fibers. Lower temperatures mean more stringent rules for care of the quilt, you can’t iron it, must wash on low, etc. Newer polyester fiber is in several brands of monofilament. My experience has been with Superior’s Monopoly. It requires a couple more ‘numbers’ lower on the top tension and I do tend to go slower with it. But it really has a nice look, washes on medium heat, and can be ironed. It’s great for trapunto too. Monopoly is slightly matte and that helps it disappear too. It comes in a light/clear and smokey clear for using on darker fabrics. I don’t hesitate to use the light monopoly on dark fabrics if I do not have the smoke available. It really is fun to use.