When I first started to learn to sew with interfacing, I just looked for “fusible” and grabbed the first one I saw, thinking they were all basically the same aside form fusible/non-fusible differences. However, there are several (and I mean several) different types of interfacing for different projects and fabrics.
Choosing Interfacing Based on Fusibility:
So you know the basic differences between fusible interfacing and non-fusible interfacing, but you want to know when to use one over the other. As a general rule, fusible is better for beginners. Non-fusible (sew-in) interfacing can add bulk to a project that may be difficult for a beginner to handle. Attaching fusible interfacing is also a great way to practice your pressing! It uses less thread and is ( at least I think) a little less time-consuming.
However, sew-in interfacing looks more natural than fusible. Also, if your fabric cannot be pressed you obviously cannot attach a fusible interfacing to it. Here is a handy guide to fabrics that you generally should not hit with an iron or fusible interfacing.
Choosing Interfacing Based on Composition:
There are three basic classifications of interfacing based on composition: woven, non-woven, and knit. The differences are pretty easy to remember!
Knit interfacing is generally used for very stretchy knit fabrics, like jersey, because the interfacing can stretch with the fabric. Using a woven interfacing on a very stretchy fabric will inhibit its movement.
Woven interfacing should be used on very fine fabrics like silk. Woven interfacing has a grainline just like a woven fabric, so you have to cut the interfacing to match the grainline of your fabric, which helps the garment or craft stay true to its shape but can be a little challenging and takes up more of your material. Don’t use woven unless you absolutely need it!
Non-woven interfacing is a nice all-purpose interfacing for most projects, unless you’re using a very fine or very stretchy fabric. It does not have a grainline, so you can cut it in any direction, which makes it a more economical choice. As a beginner, this is what you should choose pretty much every time you have to buy interfacing.
Choosing Interfacing Based on Weight:
Finally, you have to consider the weight of your fabric and how it will be used when choosing interfacing. Aside from some specialty types of interfacing, interfacing is basically classified into a few groups based on weight:
- Featherweight interfacing – Also called “sheer.” Use featherweight interfacing for very, very light fabrics.
- Lightweight interfacing – The go-to for most garments.
- Medium-weight interfacing – I would recommend medium-weight interfacing for crafts that you need to hold some shape but don’t want to be too stiff, like tote bags.
- Heavyweight interfacing – This is best for most home decor, and when you need a project to hold a rigid shape.
In general, you should simply match the weight of your interfacing to the weight of your fabric. I’ve also heard that when in doubt between two types of interfacing, go with the lighter weight to play it safe. An interfacing that’s too heavy for your fabric will give it a strange appearance when finished.
If all of this seems a little overwhelming, don’t worry! You’ll get the hang of it soon. Plus, several fabric stores actually have an interfacing guide next to their rack of interfacing bolts to help you choose the right one for your project.