Silly sewing question

John,

I am in the middle of my first sewing class, and it is a blast.

Yes, the bobbin thread is the same as the top thread. You will need to learn to fill a bobbin, before you can sew. Also, practice threading and unthreading your machine, you will be doing this many times.

I have been testing different needles for use with silnylon, 70D nylon, cordura, etc. Right now, I am using a #14 needle, and just purchased a walking foot, to help keep slippery material together.

I am almost done with my rain pants, and will start the rain jacket, to match.

Great Fun,

Z.

Actually, it doesn't need to be the same. most of the time it is, because that's just easier, but not always.

if for example, you were sewing a fabric with different colored faces (say a lined softshell fabric) you could use two different colors. But you would probably use the same weight and type of thread.

for silnylon use a really tiny needle to minimize leaking of water through needle holes. the smallest size that can handle the thread you're using, which will depend on how strong you need it to be, but should be synthetic so it doesn't wick water through the seam.

John,
I don't think the thread size has to be the same top and bottom, but I can't think of a reason you would use different sizes except for appearance.

Top thread in picture is heavy duty Gutterman polyester. Bottom is standard Gutterman polyester. For silnylon projects, I think standard thread is sufficient.

I've had good success with #70(aka #10)needles. It's a good compromise between hole size and durability. I've used #65 (aka #9) but bent or broke quite a few. #80 is more durable yet, but overkill unless you're sewing grosgrain or webbing to silnylon, or are sewing material heavier than silnylon.

Don't wait for a needle to bend or break before replacement. They do get dull. One new needle should be good for one tarp, tarptent, or quilt.

Picture shows product I use. Ran out of #70, so not in the picture.

Happy sewing!

If you mix different thread sizes top and bottom, you may find you need to change the top or bottom thread tension to still get a "balanced stitch".

The reason is that the thread tension is set mechanically with friction between the disks in the upper tension and between the bobbin case and the thread spring in the lower tension.

The bigger the thread diameter, the greater the thread tension induced by the tension device. It may or may not be enough of a difference to alter how neat the stitch is. You will notice it in the crossing of the upper and lower threads being more toward the top or the bottom of the seam. And, you may or may not care about that part of the appearance.

Hopefully, you have an instruction book which illustrates getting a balanced stitch.