To Fuse or to Sew, That is the Question
Interfacing. It's one of those things that you don't think about until you need it. But when you do need it, it's vital to your project. So, what is interfacing and what is best for your project?
Interfacing is a material used to give extra support or structure to fabrics. It's usually made from synthetic fibers, like polyester or nylon, and comes in both woven and non-woven varieties. It's often used in garments to give shape or to reinforce areas like the bust or waist, or in crafts to stabilize fabric for embroidery or applique.
Interfacing Types
There are two main overarching types of interfacing: fusible and sew-in. Fusible interfacing has an adhesive on one side that allows you to attach it to fabric using heat. Sew-in interfacing doesn't have any adhesive; instead, it's usually basted to the fashion fabric before construction. Both have their pros and cons, which we'll explore in more detail below.
Within each main type of interfacing are different types of weaves: woven, non-woven, and knit. Woven interfacing has a tight, compact weave that makes it ideal for firm fabrics such as denim. Non-woven interfacing is made from short fibers that are bonded together with heat and pressure. It's often used for lightweight fabrics such as chiffon or silk. Knit interfacing has a stretchy, fabric-like quality that makes it perfect for Lycra or other stretchy fabrics.
Additionally, weft insertion is a type of interfacing that's often used in tailoring. It's made from long fibers that are woven into the fabric to add strength, stability, and soft body.
Fusible Interfacing
Fusible Interfacing Pros
Easy to use—simply iron on
Can be used on a variety of fabrics
Gives a professional finish
Holds its shape well
Fusible Interfacing Cons
May not be as durable as sew-in interfacing
Some fusible interfacings can be difficult to sew through
Fusible sometimes dislodges from fabric and creates 'bubbles' after wear
How to Apply Fusible Interfacing to Fabric
*Always refer to product and distributor instructions.
Cut the interfacing pieces slightly smaller than the fabric pieces they will be reinforcing. This will prevent the interfacing from peeking out from under the seam allowance and fusing to your ironing surface or your iron.
Place the wrong side of the fabric against the wrong side of the interfacing. Make sure that the glue side of the interfacing is facing up!
On a synthetic setting, press firmly over the entire surface area holding for 10-15 seconds. Be careful not to slide the iron around, as this will cause the interfacing to shift out of place. Be sure to check product instructions since some fusible requires steam while others do not.
Allow the fabric and interfacing to cool completely before handling them further. Once they're cool, you can trim away any excess interfacing if necessary. Your fused pieces are now ready to sew!
TIP: This is a great place to use a non-stick, teflon press cloth in case bits of the interfacing peek out from under the piece.
Sew-In Interfacing
Sew In Interfacing Pros
Durable and long lasting
Can be sewn through without any problems
Won't melt if it come into contact with a hot iron
Sew-In Interfacing Cons
Takes longer to apply than fusible interfacing
How to Apply Sew In Interfacing to Fabric
Unlike fusible interfacing, cut your sew-in interfacing the same size as the corresponding fabric pieces.
Place the wrong side of your fabric against the wrong side of your interfacing piece and pin them together securely, matching the cut edges.
Sew the two layers together either by hand or machine using a straight stitch and a moderate stitch length. Sew along all four sides of each interfacing piece, making sure not to snag any other layers as you go.
Once attached, treat the interfacing and fashion fabric layers as one - constructing the garment as normal.
Now that we've gone over some of the pros and cons of each type of interfacing, you might be wondering which one is best for your project. The answer really depends on what you're looking for . If you need something quick and easy, go with fusible interfacing. But, if you want something that's more durable then sew-in interfacing may be the better option. Of course, there are always exceptions to every rule, so make sure to test out a small sample of both before committing to either one!
Considerations
Weight
When it comes to weight, interfacing should generally be the same as the fabric, or a bit lighter. The weight of the interfacing will depend on the weight of the fabric. For example, a lightweight fabric will require a lightweight interfacing. A heavyweight fabric will require a heavyweight interfacing. The weight of the interfacing should match the weight of the fabric so that it provides the necessary support without adding unnecessary bulk. In general, it is better to err on the side of using a lighter weight interfacing rather than a heavier weight interfacing.
Pre-Shrinking
Anything that you add to your garment should be pre-shrunk before sewing it on, and that includes interfacing. You might be thinking, "Why pre-shrink interfacing? It's so small and unnoticeable." But trust me, pre-shrinking your interfacing is important if you want your garments to last. When you pre-shrink interfacing, you're basically pre-washing it. This helps to remove any chemicals or sizing that could cause problems later on. It also ensures that the interfacing will shrink at the same rate as the fabric, which prevents it from distorting the shape of your garment. Take a minute to pre-shrink it first - your garments will thank you for it!
IMPORTANT: As tempting as it may be, do not put fusible interfacing in a laundry machine or dryer. The heat and agitation will melt the glue on the fusible interfacing. What once went in as pristine interfacing will be removed as a useless ball of glued fabric.
To pre-shrink your fusible interfacing, you'll need to hand wash it. Soak the interfacing in water, then hang it up to air dry. Be cautious of the weight of the interfacing while hanging to dry, as this can distort the grainline. Instead of hanging it to dry, you may choose to dry the interfacing lying flat to reduce distortion. Once the interfacing is dry, it will be ready to use.
Grainline
Grainline can be a tricky thing to pay attention to, especially when working with non-woven interfacing. Yet, it's important to keep in mind that woven and knit interfacings do have a grainline, even if it's not always immediately obvious. Grainline is the direction in which the fibers in the fabric are oriented. When cutting interfacing, you'll want to follow the pattern instructions for grainline positioning. This will ensure that the interfacing doesn't stretch or distort the fabric. It may seem like a small detail, but paying attention to grainline can make a big difference in the finished product.
Bulk
As a sewist, there are a few things you always want to avoid. One of those things is adding bulk in seams and seam allowances. This can make your garments look lumpy and unprofessional. It can also make them difficult to sew. So, how do you avoid this problem? The key is to be cautious when interfacing. You want to use the lightest weight interfacing possible. And, you want to apply it sparingly in areas where you need a little extra support. If using a heavy weight fabric, consider removing the seam allowances from the interfacing to lower the amount of bulk in the seam.
Common Interfacing Applications
Stretch Fabric
Knit interfacing is the best type of interfacing to use when sewing a stretch knit garment. It has the right amount of stretch and recovery to keep your garment looking great. Plus, it's easy to work with and provides just the right amount of structure. If you're looking for a knit interfacing that's easy to work with and provides just the right amount of stretch and recovery, my top recommendation is
Woven Dress or Top
There are a few varieties of interfacing that can be used for woven fabrics, but the best one to use depends on the project. For a light dress or top, a woven interfacing is ideal. It will add just a bit of structure without adding bulk. For a heavier woven fabric, like denim, you may want to use a non-woven interfacing. This will give more support to the fabric and help it hold its shape. And for a very delicate fabric, you might even use a fusible interfacing. This will give the fabric extra stability without changing its hand. When it comes to choosing an interfacing it really depends on the weight and type of fabric you're using.
Textured Fabric
When choosing an interfacing for highly textured fabric, such as a pleated skirt or fur coat, it's important to consider the weight, drape, and nap of the fabric. It’s easier to use sew-in interfacing for textured, pleated, and napped fabrics. These fabric types can be crushed and damaged by heat, so avoid using fusibles here.
Structured Bag
If you're looking for a little structure in your life, interfacing is the key. A structured, heavy weight interfacing gives the support and structure you’ll want in this instance. It can be either sew-in or fusible, but I prefer fusible because it actually sticks to the fabric and transforms it into something more sturdy. Sew-in interfacing sort of lives next to the fabric, so even though it gives the bag the structure it needs, the actual fabric itself might still be floppy-looking. This is especially apparent when there's a gap between the interfacing and the main fabric.
Woven Waistband
In my opinion, non-roll, non-crush Ban-Rol makes the perfect waistband interfacing. It makes the waistband stiff in pants to provide a crisp edge that won't roll or collapse. I found this product a couple years ago, and have used it in every structured waistband I’ve made since then. Keep in mind, this will only work in straight waistbands since the Ban-Rol does not curve.
Conclusion
So there you have it- a comprehensive guide to interfacing types and weaves. We’ve looked at the pros and cons of both fusible and sew in interfacing, as well as some use considerations. Hopefully this article has helped clear up any questions you may have had about interfacing. And if there’s something I missed, be sure to let me know in the comments below so I can add it to this comprehensive guide.