How to Sunday - how to choose the right interfacing

Interfacing is something that you never see, and a boring topic really, but I always end up using at some point in sewing or quilting. The patterns usually indicate what you need – as long as you use the same the fabric as the pattern recommends. I seem to have to adapt patterns as I choose different fabrics like for the Cami dress (my fabric was heavier than the one recommended), or the toffee chooing clutch (for which I used faux-leather).

So what do you need to know about interfacing to choose the right one for your project.

A thing called interfacing

Interfacing is the additional layer applied to the inside of garments, in certain areas only, to add firmness, shape, structure, and support to areas such as collars, cuffs, waistbands and pockets; and to stabilise areas such as shoulder seams or necklines, which might otherwise hang limply. Interfacing can be used in quilting to apply an applique, stabilize a lighter fabric, and prevent fraying.

Interfacing -- Basic Choices

Interfacings come in two main types (fusible or sew-in), three main weaves (non-woven, woven and knit), and in different weights (light, medium, heavy weight).

The weight of the interfacing should generally be the same as the fabric, or a bit lighter. Generally you should not use a heavier weight interfacing than the fabric, as the interfacing will ‘dominate’ the garment and add an unnatural structure to it. So for medium weight fabrics, use medium weight interfacing. For medium weight knit fabrics, use medium weight knit interfacing. As a general rule, if you try and match the properties of the fabric to the properties of the interfacing, you can’t go far wrong – for very sheer or lightweight fabrics, you can even use a second layer of the main fabric as a form of sew-in interfacing!

The fabric choice is key. Not all fabrics can withstand the heat required for fusible interfacing. Cool Fuse interfacing is a possibility because it adheres at a lower heat setting. Fusible interfacing also adds a bit more stiffness once it is fused than when it is standing alone. 

Fusible	By far the easiest to use. It has an adhesive on one side which bonds permanently with the fabric when applied with an iron, due to the combination of heat and steam – giving complete contact.	Fusible interfacing is suitable for most uses
Sew In	Sew-in interfacing is sewn on to the main fabric just like another normal layer of fabric, and is held in place by the stitches. Sew-in interfacing can result in a more natural shaping and drape as there is less “stiffness” to it.	·   very textured fabrics – the glue won’t bond well to the fabric ·   napped fabrics (e.g. velvet / fur) – the pressing needed to bond the adhesive will crush the fabric ·   fabrics that are very heat sensitive – e.g. sequins, metallics, vinyl fabrics (the heat can melt or distort the fabric) ·   fabrics with a very loose or open weave e.g. lace, mesh (the glue may seap through to the right side of the fabric)
Woven	Like woven fabric, has a lengthwise and crosswise grain. When you cut woven interfacing, be sure to match the grain of the interfacing with the grain of the part of the garment to be interfaced, to make sure the two layers of fabric work together properly. Because of the need to match the grainline, it is less economical than non-woven interfacing, which can be cut in any direction.	You only really need to consider woven interfacing for particularly fine fabrics such as sheers and silks, where a very natural shaping is essential to preserve the qualities of the fabric.
Non woven	Made by bonding fibres together and therefore has no grain. You can cut it in any direction, plus it will not ravel.	Non-woven interfacing is suitable for most tasks unless you are sewing with a jersey of stretch fabric in which case knit interfacing is appropriate
Knitting interfacing	made by knitting the fibres together, and so it has an amount of stretch in it.	Knit interfacing is especially suitable for use with jerseys and other stretch fabrics as it will stretch with the garment and not hinder it (if you apply woven interfacing to a knit fabric, you reduce the fabric’s stretch properties as the interfacing layer is unable to stretch with the outer fabric layer).

Colour of interfacing

Interfacings generally only come in a dark shade (black / charcoal) or a light shade (white / cream). Simply match up the darkness of the interfacing with the shade of the fabric.

MiH Tips about interfacing

· The first step is to identify which side of the interfacing has the adhesive on it. The adhesive side normally has a slightly bobbly, raised appearance, and usually you can see a slight shininess from the glue.

· Before you apply interfacing to your main fabric, it is worth doing a test using a scrap piece of fabric and interfacing. This will let you check that the weight of the interfacing is suitable and that it results in the right amount of shaping to the garment. If you find the end result is too “stiff”, you should try a lighter weight interfacing; if the result is too flimsy, try a heavier weight.

· When choosing the heat setting, it’s usually appropriate to use the “wool” setting for medium or heavy weight fabrics. For light weight fabrics, use a heat setting slightly higher than that which you would use directly on the fabric (as you have the press cloth as a protecting layer in between). When you do your test piece at the beginning, it’s a good time to check the temperature setting is appropriate – too hot and you’ll damage your fabric, too cool and the adhesive won’t bond to the fabric properly.