Guide: Choosing Interfacings

Understanding Interfacings

"An interfacing is a layer of fabric between the facing and outer layer of a garment. Its purpose is to add any needed firmness, strength, or stability, while adding as little bulk as possible."1.

Interfacings are either woven, non-woven, knit, or weft insertion interfacings. Wovens can be either sewn-in or fusible. Non-wovens are not something we need to be concerned about when making a coat, and knit and weft insertion (or textured weft—I use the terms interchangeably—probably shouldn't) interfacings are primarily fusibles.

Traditional tailoring is done with traditional materials and sewn-in interfacings. However, in light of today's improved processes for creating quality fusibles, and in consideration of time and cost, even high-end designers are using some fusibles in their pret-a-porter jackets and coats now. I understand that such sewing luminaries as Nancy Erickson have also had great success tailoring with fusibles, even on cashmere.

I'm going to present both options, and it's up to you to decide. Are you going to speed tailor using fusible interfacings, or are you going to traditionally tailor using sewn-in interfacings? Or are you going to do a combination of both? You have to balance your time with the amount of work you want to put into this garment and make your own decision. Either way, with care and good workmanship, you'll end up with a garment to be proud of.

In the Feb/Mar 1990 issue of Threads Claire Schaeffer took apart a Dior RTW suit and analyzed the combination of fusible and sewn-in interfacings used. In the April/May 1999 issue Marci Tilton dissected an Armani jacket, which used primarily fusibles, and outlined the process in an article which is reprinted on their site.

Illustration belongs to Taunton Press, "Armani Jackets: The Inside Story"

Click on the photo to link to the article. If you want to speed-tailor with fusibles, this article is a must-read. I've successfully used that method making a silk tweed suit last year.

All that out of the way, I'm a traditionalist at heart. I love the process, and I personally just can't imagine putting my luscious 100% cashmere fabric into the Elnapress with a piece of fusible interfacing, so I'll be using sewn-in hair canvas to interface, and woven fabrics to underline.

Where to Apply Interfacing

Areas that will be interfaced:

• front

• side front if there is a pocket that extends across a princess seam—either patch or welt pocket

• back stay—shoulder area across the back. This may be hair canvas or tightly woven muslin or a weft insertion fusible

• pockets, collars

• hems will either be interfaced with a bias strip of hair canvas or with the wiggan I've already specified.
  

Make sure when buying interfacing you buy enough—don't count on your pattern envelope to allow enough for a fully interfaced garment. All too often the pattern companies are just figuring enough interfacing to have you cut the front facing and collar.

Determining the Right Interfacing Weight

The weight of interfacing you choose will be determined by the weight and the weave of your fashion fabric. The lighter weight your coating fabric, presumably the lighter your interfacing will be.

Here's a test to help you select interfacings: Layer a piece of your fashion fabric, underlining or interlining if you're using one, the interfacing you're considering, and then sandwich another piece of your fashion fabric around the back. Now roll this over your hand. Does the whole feel pleasing and balanced? Does the interfacing support the fabric over your roll line? Does the weight of the fabric cause the roll line to collapse? You need a heftier interfacing. Try a midweight or heavyweight interfacing. Does the interfacing make the roll line feel rigid? Try a lighter weight interfacing.

Recall the words of Adele Margolis that I quoted at the top of the post about Linings. Your coat shouldn't feel like a suit of armor! Go with the interfacing that gives enough support without overwhelming your coat.

If you're using a fusible to interface, you will want to cut a 6"x8" piece of your fashion fabric, then fuse a 4x6 piece of the interfacing, then fold the rest of the facing piece over, then evaluate using the same criteria as above. You may be using a fusible textured weft insertion product to underline. In that case, fuse your fashion fabric before testing the interfacings.

I can easily see a coat that is fused with Armo-weft as an underlining, then has fused woven interfacing through the lapel and collar area. Just test all your pieces together before cutting to make sure that you don't have a rigid piece that will stand on its own.

What I Know About Fusible Interfacings

You really need to test fuse to know what the result will be.

I just found out why Whisper-Weft ends up more firm than Armo-Weft, which I've experienced empirically, but it's been counter-intuitive so I've always doubted my senses. Whisper-Weft is a softer knit base, Armo-Weft is a heavier knit base, so the expectation is that Whisper-Weft would yield a softer fused fabric—wrong. The base is more closely knit on Whisper-Weft than Armo-Weft, so that when it's fused it actually yields a firmer fabric.

While not a fusible, here's an interesting little bit about the "hair" in hair canvas

"Cashmere fibers must be separated, either by combing out the down or by using a commercial dehairer on sheared fibers. The longest, finest down is used in knitted garments and the shorter down in woven fabrics. The separated guard hairs go into rugs or hair canvas used in tailored garments.

The majority of the world supply of cashmere has come from Afghanistan, Iran, Outer Mongolia, India, and China. In recent years, when these countries' political disarray disrupted cashmere supplies, manufacturers began looking for more stable sources.
New Zealand and Australia have been producing cashmere for more than a decade. Breeding selection began even some years earlier with captured feral (wild) goats." —click for the rest of the article from UC Small Farm Program USDA

1.Margaret Deck Komives in an article entitled "Making Sense of Interfacing" Threads Magazine issue 10 April 1987