However, not all interfacing is fusible. Some forms of interfacing are non-fusible and cannot be attached just using steam and heat.
Fusible interfacing is a really great tool for giving shape to your projects and doesn’t require being stitched onto fabric. Non-fusible interfacing is sometimes called “sew-in” interfacing because it doesn’t have an adhesive side like fusible interfacing does and has to be attached by being sewn to the fabric.
The process of attaching non-fusible interfacing differs a little bit from attaching fusible interfacing, so here’s a guide to using non-fusible interfacing to give a project some shape.
First, you’ll want to cut out your pattern pieces. I’m demonstrating on a Christmas stocking, and I’m attaching interfacing to the lining so that it holds the stocking shape.
Notice that I cut out the interfacing to be the exact same size as the fabric piece. When cutting out fusible interfacing you also cut it to be the same size at first. However, non-fusible is different in that you don’t trim the edges before attaching.
Pin the interfacing to the fabric, matching the raw edges.
Tip: Notice that my pins are not right along the raw edge like you normally do when pinning together two pieces of fabric. I also used as few pins as possible. This is because the interfacing is very thick and can get distorted easily with the pins. I removed the pins as I stitched to keep the edges as even as possible.
Before you stitch, you should have decided how wide your seam allowance will be. When you stitch the interfacing onto the fabric, you’ll want to use a slightly shorter seam allowance so that the interfacing will definitely be stitched into your seam.
For example, I typically use a 1/2 inch seam allowance. So for this piece of fabric, I’ll be using a 3/8 inch seam allowance when attaching my interfacing.
Stitch the interfacing onto the fabric as a normal straight stitch.
After you stitch the interfacing onto the fabric, trim the interfacing very close to the stitch to reduce bulk in your seams. This is why you have to use a shorter seam allowance rather than one that is the same length that you normally use. After you trim your interfacing, you can still be sure that it will be in your line of stitching and give your fabric a smooth look.
Now your interfacing is attached directly to the fabric. Remember that non-fusible interfacing is different from fusible in that when attaching fusible, you trim the edges before you attach. As you can see with the non-fusible interfacing, you trim after you attach.
Next I repeated this process on the matching piece of fabric and stitched the two together to form the lining of the stocking. When I stitch the seam, notice that the seam stitch is slightly deeper than the stitch used to attach the interfacing.
The stitch closer to the raw edge is the stitch used to attach the interfacing, and the deeper stitch is the seam.
All in all, non-fusible interfacing is no more difficult to attach than fusible. I tend to prefer fusible because you don’t have to use as much thread and it sticks directly to the fabric. When stitching my non-fusible interfacing, I had trouble with the fabric and interfacing becoming separated and throwing off my stitches which isn’t a problem I have with fusible.
Remember to use the interfacing guide at your fabric store if possible to pick the right interfacing for your project!