Sew in interfacing vs fusible:
Interfacing gives structure to “limp” fabric. There are 2 main types: sew-in and fusible.
The first is sewn onto the fabric, and the second is glued on using an iron. You can buy woven and non-woven versions of both. They come in different weights and colors too.
I can’t say that one is “better” than the other.
They are each better for certain situations, which you’ll learn about today!
I would definitely keep both in my fabric stash.
Related article: What is Sew-In Interfacing? 6 Types Explained & When to Use
Sew-in interfacing vs fusible: what’s the difference?
| ———— | Sew-in interfacing | Fusible interfacing |
|---|---|---|
| How it’s applied | Sew around the edges | Glued on using an iron |
| Speed | Slower (baste and sew) | Fastest (just iron) |
| Effect on the fabric | Softer effect. It doesn’t change the look & feel dramatically. | Changes the fabrics look & feel. It can sometimes be too stiff. |
| Fabrics it suits: | – Heat sensitive fabrics – Napped fabrics – Loosely woven fabrics – Textured & pleated fabrics | – Most knit & woven fabrics |
| Construction | Woven & non-woven | Woven, non-woven & knit |
| Weight | Light, medium & heavy | Light, medium & heavy |
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Fusible interfacing: the pros and cons
Pros
- It’s quick and easy to apply.
- It works for most fabrics.
Cons
- It can change the look and feel of your fabric too much.
- You could get “bubbling” if the glue starts to unstick.
- It can destroy heat-sensitive fabrics.
- It can damage napped fabrics.
- It doesn’t suit fabrics with a loose and open weave.
- It will flatten textured, pleated, and crinkled fabrics.
- It can be messy to apply. You might get it on your iron, or stuck on your ironing board.
Quick & easy to apply
Just iron fusible interfacing onto your fabric. That’s it!
In comparison, sew-in interfacing needs to be basted to the fabric by hand or machine (“basting” is temporary stitching used to hold something in place). Then you sew it on with your sewing machine.
Suits most fabrics
Fusible interfacing is a good option for most fabrics.
Use a fusible knit interfacing for stretchy fabrics. This will stretch with your fabric.
For woven fabrics, you can use a fusible knit or woven interfacing.
Yes, I said knit!
I learned this tip from sewing factory owner Kathleen Fasanella: “My default choice in interfacing is that knit fusible stuff. It works great anywhere and on nearly everything.”
Once ironed, a fusible knit interfacing won’t stretch anymore. It will act like normal woven interfacing.
Using knit interfacing on knits and woven fabrics is a great way to save on interfacing costs.
Big changes
Fusible interfacing sticks to the fabric. It can really change your fabrics look and feel.
You might find it looks stiffer than you want.
If you want a drapey and natural look, sew-in interfacing might be a better option.
Lightweight fusibles are less likely to have this problem.
Bubbling
If you don’t pre-shrink fusible interfacing, ugly “bubbling” might appear on your fabric when it’s laundered.
This happens because the fusible interfacing shrinks at a different rate as your fabric when washed.
If the interfacing shrinks too much, it will pull away from the fabric and create “air bubbles”.
Maybe you have seen this bubbling on interfaced collars before?
There are some exceptions.
Some fusible interfacings say “there is no pre-shrinking required”, like the Pellon PLF36. In this case, I expect the manufacturer has tested the material and found no shrinkage problems.
Heat-sensitive fabrics
Applying fusible interfacing can melt and destroy heat-sensitive fabrics.
For example, sequins, beading, vinyl, and metallic fabrics. These materials don’t like irons!
Napped fabrics
Napped fabrics like velvet and fur can be crushed and damaged by the heat from irons.
Therefore ironing fusible interfacing to them is difficult.
Loosely woven fabrics
Fusible interfacing doesn’t suit fabrics with a loose and open weave, like lace.
There are too many gaps in the fabric, so the interfacing will have nothing to stick to in these areas. The glue dots might also seep through the gaps.
Textured fabrics
Trying to iron fusible interfacing to textured and pleated fabrics will ruin them. The heat will permanently flatten the lovely textures.
The pros and cons of sew-in interfacing
Pros
- It has a more natural look and drape.
- You won’t get “bubbling” on your shirt collars, for example.
- It won’t damage heat-sensitive and napped fabrics.
- It won’t flatten textured and pleated fabrics.
- It’s easy to take off and reapply. Just unpick the stitches.
Cons
- It takes a while to baste, stitch, and trim it. By the way, I don’t recommend skipping the basting. Without it, your layers might shift when sewing.
- Let’s say you’re interfacing a bag. If there’s a slight gap between the main fabric and interfacing, your bag might look sloppy and unstructured.
Good for heat-sensitive & textured fabrics
Fusible interfacing needs to be ironed on. If you’re using a heat-sensitive fabric, like sequins, or something textured, it can damage it.
This is where sew-in interfacings come to the rescue.
There is no heat involved. You sew around the edges to attach it to the fabric.
Have you decided that sew-in interfacing is what you need?
Check out my article on the 6 types of sew-in interfacing you can buy. From silk organza to hair canvas, I talk about which ones work best for different projects.
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Which interfacing is better for your project?
For stretch fabric projects, like a t-shirt:
Use a fusible knit interfacing in the same weight, or slightly lighter.
This will stretch with your main fabric.
Your t-shirt will also become stronger and less likely to stretch out over time.
I like to use it in the hems of thin knits that will pucker and stretch when topstitched. It strengthens the hems and keeps my stitching flat.
Some knit interfacings have 2-way stretch, and others have 4-way.
I prefer to buy the 4-way ones. They’re more versatile because they can stretch in all directions.
For a woven dress or top
Let’s say this dress or top is a medium weight cotton that’s tightly woven. I would interface the facings with a light to medium weight fusible interfacing.
If it’s very loosely woven, I would use sew-in interfacing. I wouldn’t want the glue from fusible interfacing struggling to stick to this fabric, or seeping through it.
For a pleated skirt or a fur coat:
It’s easier to use sew-in interfacing for textured, pleated, and napped fabrics. These materials can be crushed and damaged by heat, so I would avoid fusibles here.
For a structured bag
The key to getting good structure in your bag is picking a structured, heavy weight interfacing.
Sew-in or fusible interfacings are both an option.
I prefer fusible, however. It will stick to the fabric and transform it into a structured material.
A sew-in interfacing “lives” next to the fabric. It doesn’t directly change its properties.
So my main fabric might still be floppy looking, even though the bag has the structure it needs.
This is more obvious when there’s a gap between the sew-in interfacing and the main fabric.
“Can I use fusible interfacing instead of sew-in?”
Maybe your pattern is telling you to use a sew-in interfacing, but you only have fusible on hand.
Can you swap them?
The answer depends on what your fabric is, and how you want the item to look and feel in the end.
Is your fabric:
- Heat sensitive?
- Napped? (eg. velvet)
- Textured or pleated?
- Loosely woven?
If you answered yes to any of the above, I would avoid using a fusible interfacing.
If you said no, you might be able to swap your interfacings. I would test it out.
Also think about whether you’re OK with the look and feel of your fabric changing.
If you’re not, and you want to keep its natural-looking drape, stick to sew-in’s.
Can you sew in fusible interfacing?
Technically, yes.
You can attach fusible interfacing by sewing around the edges, not ironing it.
However, it’s not designed for this.
I’m not sure the fusible interfacing will stand up well to laundering. It’s not securely attached the way it’s designed to be.
Which side of the interfacing is fusible?
One side is smooth, and the other is bumpy with tiny glue dots. The side with the dots is the fusible side.
It can be hard to see the white glue on white interfacings, so look closely and feel for the bumpy side.
The glue dots are easy to see on black interfacing.
More about this topic
What is Sew-In Interfacing? 6 Types Explained & When to Use
How to Use Fusible Interfacing Correctly (Apply & Prewash)