You can spend ages picking the right vinyl or lining, then reach for whatever thread is already in your machine. I get it. But thread affects how your seams sew, how your topstitching looks, and how well your finished bag holds up to use.

If you're trying to decide between Glide, Tex 45, and Tex 70, start with the bag you're making and the machine you'll sew it on.

First, what does Tex mean?

Tex is a measure of thread size. The higher the Tex number, the heavier the thread. In this guide, Glide is approximately Tex 27, followed by Tex 45 and then Tex 70. Heavier thread makes more visible stitches, but it also needs a suitable needle and a machine that can feed and tension it reliably. Thread size alone doesn't tell you how strong every brand of thread will be.

Glide thread: Smooth stitching for lighter work

Glide is a smooth polyester thread, commonly labeled 40 wt or Tex 27. I like it for quilting bag panels and adding decorative stitches without a heavy thread sitting on top of the fabric. It also works well for lighter projects made from quilting cotton.

For a bag that will carry heavier items, I'd choose a heavier construction thread for the seams that take the most strain. Glide is especially useful when you want a finer stitch or a lighter bobbin thread that works well with your machine.

Tex 45: A versatile choice for many bags

Tex 45 thread gives you more visible topstitching than Glide without the bulk of Tex 70. It's a practical starting point for wallets, pouches, smaller handbags, and many everyday bag seams. It can work with cotton, lighter canvas, and some vinyl projects, depending on the layers and your machine.

Many domestic machines handle Tex 45, but try it on scraps from your actual project before sewing the bag. If the bobbin thread doesn't feed smoothly, test a finer coordinating thread in the bobbin and adjust your tension on a sample.

Tex 70: Bold stitching for sturdy bags

Tex 70 is a heavier thread that creates noticeable topstitching and is often used for totes, backpacks, and bags made with multiple layers of waterproof canvas, vinyl, or faux leather.

It's a natural fit for many industrial machines. Some domestic and semi-industrial machines can sew Tex 70, while others struggle with it, especially in the bobbin or through bulky seams. Check your machine's thread and needle guidance, then sew a test seam through the same number of layers as your project. If your machine sews Tex 70 on top but dislikes it in the bobbin, you can test Tex 45 underneath and adjust the tension until the stitch is balanced.

How I choose thread for a bag

1. Think about use. A small pouch and a tote that carries heavy items put different demands on their seams.
2. Look at the layers. A thread that sews nicely through two fabric pieces may behave differently where straps, stabilizer, and seam allowances meet.
3. Test the complete combination. Use your project fabric, the planned needle, and the same top and bobbin threads you'll use on the bag. Check both sides of the stitch and try a bulky seam, too.

If you're sewing on a domestic machine and aren't sure where to begin, Tex 45 is a sensible first test for many bag projects. Choose Glide when you want finer decorative stitches, or try Tex 70 when you want a bolder stitch and know your machine can handle it.