Dog Under My Desk had a good article on woven vs non-woven so I thought it would be useful here.

Interfacing – Woven vs. Non-Woven

I have been working with interfacing a lot this week. I had started to write what quickly turned into a long, overwhelming rant about interfacing. Interfacing is a very personal preference type thing, but it also helps to know the basics when deciding which to choose. So considering that, I might approach this differently and a little bit at a time. Interfacing is important. It can help stabilize stitching, stiffen fabric and help achieve a different look or feel for your final project. If you want your bag to stand up or have a padded look or if you want your straps to be sturdy and not flimsy, the right kind of interfacing can make all the difference.

There are 4 main types of interfacing:
Woven Fusible
Non-Woven Fusible
Woven Sew-in
Non-Woven Sew-in

Fusible Pros:
Stays in one place and does not shift.
Stabilizes the fabric and make it easier to work with.
Makes the fabric thicker or stiffer.

Fusible Cons:
It can drastically change the drape of the fabric (sometimes this matters, sometimes not so much.)
It can wrinkle or dimple *even* if you fuse it flat and correctly.

Sew-in Pros:
Adds thickness, stiffness and stability to the fabric without completely changing the behavior of the fabric.
Does not leave wrinkles or dimples like fusibles can.
Easy to go back and cut excess interfacing from seams to reduce bulk.

Sew-in Cons:
Does not make fabric easier to feed through the sewing machine.
You will have more layers to keep track of and line up, oh and pin. (I hate pins… I’m enjoying the new Clover wonder clips instead.)

Why choose a woven vs. a non-woven?

If you click on this picture and make it bigger you can see the difference between the woven and non-woven. Woven is just like fabric. Non-woven is more like paper.

Woven Pros:
Moves and drapes in the same way as your fabric.
Fusible version is easy to fuse, easy to remove if you mess up.
Less wrinkles and dimples

Woven Cons:
Cost & Availability
Typically only available in a few weights/thicknesses

Non-Woven Pros:
Available in lots of weights and thicknesses
Less expensive
Widely available

Non-Woven Cons:
Fusibles can wrinkle, crinkle and dimple, especially on curvy parts of your project.
May drastically change the look and feel of the fabric
May tear more easily than woven

In general, I prefer woven interfacings to non-wovens. They have a more natural look and in the case of the fusibles, are easier to fuse. However, there are fewer choices for woven interfacing. Unless you live somewhere that has a massive craft and sewing culture, you are going to be limited by what you can easily find at the Big Box Fabric Store, the LQS (Local Quilt Shop) and online. (Which doesn’t always have the selection you would expect!)

You are typically only going to be able to find a single woven fusible from each manufacturer. In the case of Pellon, this is SF101. I back just about every piece of quilting cotton that I use with SF-101. If you plan to make a lot of bags, just buy a 15-yard bolt when it’s on sale.

Woven sew-ins are becoming more popular. Pellon has their new SF785, and some chains and LQS’s carry HTC’s Form Flex. This stuff is soft but once sewn into seams it really holds it’s shape. But since this is a single thickness, I often turn to non-woven sew-ins when I need to change the look of my project.

Non-woven sew-ins – Pellon has a wonderful new product called 926. It’s a non-woven about half the thickness as Peltex 70. I’ve been using this one a lot in The Essential Wristlet. It’s made me a non-woven fan. If you are going for a thicker, padded look, my best suggestion is to turn to Soft and Stable. You might need to order it, or look for it at your local quilt shop as I’ve never seen it at the craft stores, but it’s worth it. It replaces all but your SF-101 in your bag project – so eliminate the batting and sew-in interfacing – and that way the cost seems quite worth it for the professional looking finished results