I would be happy to help clear up some of the confusion about threads but I cannot put everything into one e-mail message so I will discuss threads in several installments. First let me confess that I am extremely biased. I only use good quality thread in my machines. I have been a Mettler thread customer for over 25 years. Why?
1) Mettler threads are made of long fiber polyester or Egyptian cotton which results in less snagging, knotting, and breaking. The cotton threads do not shrink which prevents puckering after pressing and washing.
2) Consistency of diameter results in uniformity of stitches and a free flow of thread through the guides and the needle. (This is especially important in sergers because of the number of guides through which the thread must pass.)
3) Cross wound spools mean smooth feeding on sewing machines and sergers.
4) They are twist balanced to eliminate tangling and knotting and lint resistant to minimize the collection of lint in your machine from thread.
There are other similar brands of thread on the market (Dual Duty is not one of them) but I have not had experience with them so I cannot speak intelligently about Gutterman or Molynike (sp?) threads. I have been told (even by a shop owner in Germany) that Mettler threads are the best quality in the world. They are made in Switzlerland just like our beloved Berninas. Bernina of America used to distribute Mettler threads but they have not done so for many years. I have forgotten who has the distribution rights at the present time. It keeps changing.
Dual Duty thread has a polyester core covered with shorter cotton fibers. My machines refuse to sew with it.
Since I know them the best, I thought that I would continue our discussion of thread by talking about the various products made by Mettler. First however let's talk about the little numbers that you see on the spools such as 40/3 or 60/2 etc. The first number refers to the size of the thread - the higher the number the finer the thread. The second number refers to the number of plys of that size thread which are twisted together. The more plys, the stronger and thicker the thread. Three ply thread is suitable for garment construction, 2 ply thread is generally used for decorative purposes.
1) Metrosene plus with the red label (sometimes black) article #1161 is 100% polyester 100/3. It is a three-ply thread especially suitable for sewing synthetic fibers or blends. It is very strong and has elasticity. Very good for knits as well as for wovens. Use this thread for dressmaking, home dec, crafts.
2) Silk finished cotton with the purple label article #105 is 100% cotton 50/3. Again a 3-ply thread which can be used for garment construction or quilt piecing. Use with natural fibers such as cotton and silk. (Try sewing a piece of silk with polyester thread and then with cotton thread and you should see a big difference in performance. Cotton being a natural fiber is more compatible with silk which is also a natural fiber.)
3). Cotton embroidery thread with the green label article #240 is 100% cotton 60/2.A very fine two-ply thread which is suitable for freehand machine embroidery, satin-stitch embroidery, heavy quilting, or use on bobbin for decorative work. NOT suitable for construction. This thread is not strong enough for normal construction but is used for rolling and whipping in heirloom sewing techniques.
4)Cotton embroidery thread with the yellow label article #259 is 100% cotton 30/2. Again not used for construction but this thread is a lot heavier than the 60 weight and will fill in faster for satin stitching or fill in work on the embroidery machines. This thread seems to be harder to find than the other 2 types of cotton Mettler listed previously.
5) Quilting thread with the brown label article # 136 is 100% cotton 40/3. I know some quilters who use this thread for piecing (it is 3 ply). It can be used by hand or machine. I know of no other quilting thread which can be used on a sewing machine because the finishes will destroy your machine tension mechanism. This thread will give a very pronounced look to your machine quilting stitch versus the finer look achieved with the finer cotton threads mentioned previously. My closest source of Mettler threads is an hour away and I just discovered a new quilting thread for hand quilting which has a glace finish. I don't know any details about it however. Perhaps someone else can fill us in.
6) Cordonnet topstitching thread with the blue label article #1146 is 100% polyester 30/3. As its name implies, it can be used for topstitching since it is a heavier thread. It is also used for decorative stitching such as sashiko, as a filler for finer corded buttonholes and pintucks. You can zigzag over it and pull the cordonnet to gather. It is similar to pearl cotton.
7) Gimpe is 100% cotton and is similar to a heavier weight pearl cotton. It can be used like cordonnet when a heavier thread is needed.
Next time we will talk about other types of decorative threads.
Cotton threads are softer than synthetic ones and spread out a bit on the surface of the fabric when doing a satin stitch. Also because cotton has more flexibility and less drag on your tensions, your satin stitch will be smoother and more consistent than one made with polyester. For embroidery work we normally work with 2-ply thread such as Mettler 60 or 30 weight or DMC 30 and 50. Both DMC and Mettler use long fiber cottons and are consistent in diameter which results in a smoother and more uniform stitch. For the bobbin, I recommend Mettler 60 weight thread. I have never used Bobbinfil and know very little about it. Perhaps someone else can fill us in about it. According to Harriet Hargrave, basting cotton is a short-fiber thread which creates a lot of lint, has an uneven diameter and the thickness causes excessive buildup.
For those of you with embroidery machines, I'm sure that you have found that the heavier weight thread (remember, the lower the number, the heavier the thread) the better the coverage of your design. Another alternative is to sew over the design twice.
For those of you who are wondering why I am slighting Madeira threads, it is only because I am not very familiar with them. They do make long staple Egyptian cotton threads which they call Tanne in 50 and 30 weight.
Rayon thread adds shine to your stitching and comes in a beautiful array of colors. Sulky and Madeira manufacture rayon embroidery threads. Before the Industrial Revolution, silk was used for hand embroidery because of its luster but silk is not a very strong fiber. Rayon was developed to replace silk in embroidery machines.
When choosing a thread color for dressmaking, we normally recommend selecting one shade darker than the fabric because once it is sewn into the garment, it will look one shade lighter. When doing decorative stitching, a darker thread will frame the design so that it stands out more and using a lighter thread can add a shine to the edges of your pattern. You might consider choosing your thread to match the background fabric which will make the design appear to float or match the color of the applique pieces themselves. You are the designer so choose what appeals to you the most. I'm trying to give you general guidlines but don't let yourself be totally controlled by what I say. Experiment - try new things - keep samples and jot down notes about what you did and then share it with the rest of us!
Serger threads are finer than regular sewing machine threads in order to avoid excessive bulk in your seams. Since they pass through many more guides in a serger than they do on a sewing machine, it is even more important that the thread is smooth and consistent in diameter. Lumps, bumps, knots, and any unevenness in texture will create drag as the thread passes through a guide and this results in a change in tension. We also want a thread that does not leave a lot of lint. Look at the serger thread that you are now using under a good magnifying glass and if you can get samples of other brands, compare them. Your eyes will see the difference. Lower quality thread is made of short filaments and will have ends sticking out which give the thread a hairy look. The twist may be uneven so that you get thick and thin areas. Once again, my favorite all-purpose serger thread is the Mettler brand called Metrocor.
It is best to use cross wound thread in your serger since the thread feeds off of the top of your spool. The spool does not revolve like it does on a sewing machine. It is important that the thread feed off of the spool evenly and smoothly. Any catches, no matter how small, will affect the thread tension which can result in uneven stitches and thread breakage. If you use thread that is not crosswound, be sure to use your thread caps on the top of the spool to avoid catching the thread on the notch. I often use regular Metrosene sewing thread on the small spools (they are crosswound although thicker than serger thread) in order to match thread color to my garment. My clothes are often examined inside as well as outside and serged seams in matching colors certainly look a lot nicer. For most of you, this is not necessary and you will find that if you match the left needle thread to your garment, you will not see any of the mismatched colors on the right side.