Interfacing is one of those sewing supplies that seems like it should be simple.
Put the sticky side against the fabric. Add heat. Now they're stuck together.
Except sometimes they're mostly stuck together. Or there's a bubble. Or one corner peels up as soon as everything cools. Or you've accidentally gotten adhesive on your iron and now you've created an entirely different problem.
I use fusible interfacing in most of the products I make at Momako Designs, and I've learned that getting a good result isn't always as straightforward as following one set of instructions. Different fabrics behave differently, different types of interfacing behave differently, and sometimes even the same interfacing doesn't behave exactly like it did the last time.
So I've developed a process that's a little less “press for exactly this many seconds” and a little more “I know what this stuff usually does.”
Why I usually choose fusible interfacing
For most of what I make, I prefer fusible interfacing over sew-in because I like the structure it gives the finished product. Once it's bonded to the fabric, the two layers behave more like one, which gives me a sturdier base to work with when I'm constructing a bag or accessory.
What I use depends on the fabric and what I'm making. Some projects need more structure, some need softness, and some need additional body without becoming too stiff.
I also frequently use a lighter-weight fusible interlining along with whatever main interfacing, foam, or fleece the project calls for. That extra layer has become an important part of how I construct a lot of my products — and it has an unexpected bonus when the main interfacing decides it doesn't feel like cooperating.
I don't automatically prewash everything
A lot of interfacing instructions start with prewashing your fabric, but that's not something I routinely do for every product I make.
Whether I wash fabric first depends on the material and where it came from. Most new fabric goes straight into my normal cutting and sewing process, but there are exceptions. If a fabric has a strong smell from the printing process, I'll wash it first.
I also sometimes work with vintage fabric I've found at thrift stores or fabric that was previously clothing. Those are things I'll wash before they make their way into a new product.
So prewashing isn't really a standard step in my interfacing process. It's something I decide based on the particular fabric I'm working with and whether there's a reason it needs to be washed first.
My pressing method depends on what I'm fusing
I usually start from the fabric side rather than putting my iron directly onto the interfacing. I'll use steam for most of the interfacing I work with, get everything bonding from that side, and then flip the piece over and iron directly on the interfacing.
How long? Until it sticks.
That's probably not going to appear in an interfacing manufacturer's official instructions, but after using the same materials repeatedly, you start learning how they behave. Some fuse easily and don't require much convincing. Others are fiddly and need more time and pressure.
My iron is fairly heavy, which helps because I don't have to put a huge amount of additional pressure on it myself. I also don't have one universal rule about whether the iron should move. I'll move it around with some interfacings, while the ones I know are harder to fuse get more time sitting under the iron.
The manufacturer's instructions are still a good starting point, especially when you're using something unfamiliar. But I've found that the actual fabric and interfacing in front of me ultimately tell me whether they're ready.
The ironing board matters more than you might think
I've also found that a well-padded ironing board makes fusing interfacing much easier. Having some cushion underneath the fabric helps me get good contact while I'm pressing, especially when I'm working with an interfacing that needs a little more convincing.
I go through ironing board covers fairly quickly, though, so this is not an area where I invest in particularly expensive ones. Between frequent pressing and interfacing adhesive occasionally ending up where it isn't supposed to, they're going to get worn out.
What I will pay attention to is the padding. I'd rather have a reasonably priced cover with good cushioning than spend more on a fancy cover that doesn't give me a good surface for fusing.
Some fabrics need a little more protection
I don't use a pressing cloth every single time, but there are fabrics where I absolutely do.
Corduroy is one of them. I've found that corduroy doesn't necessarily react badly to direct ironing, but it doesn't look quite the same afterward. Rather than risk changing the surface, I use a scrap piece of lining fabric as a pressing cloth between the corduroy and my iron.
That's something worth considering beyond just corduroy. Before putting a hot iron directly onto the face of a fabric, think about whether heat, steam, or pressure could change its texture or appearance.
If I'm unsure, I'd much rather find that out on a scrap than on the piece I've already cut for a bag.
Interfacing can be surprisingly inconsistent
One of the stranger things I've noticed after using a lot of interfacing is that even the same interfacing doesn't always seem to behave the same way.
I usually buy interfacing by the bolt, and I'll sometimes notice a difference when I move from one bolt to the next. It's supposedly the same product, but one might fuse easily while another takes considerably more work to get a good bond.
I don't necessarily know why one manufacturing batch behaves differently from another, but I've learned not to assume that because I've used the same interfacing for years, the next bolt is going to behave exactly the way I expect.
Sometimes interfacing is just fiddly.
And yes, I've fused things badly
I've had bubbles. I've had interfacing peel away. I've gotten adhesive on my iron. I've fused wrinkles into fabric and then had the pleasure of realizing that wrinkle lives there now.
Most of these problems aren't catastrophic, but they're much easier to deal with before you start sewing. That's why I pay attention to the surface while I'm fusing and check the bond again after the piece has cooled.
That last part matters because interfacing can look perfectly attached while it's still warm and then start lifting once it cools. If it's noticeably loose, I'll go back and give that area more heat.
Why I like using an interlining underneath
Using a lightweight fusible interlining has made some of the imperfections in heavier interfacing much less noticeable in my finished products.
The interlining tends to fuse easily and gives the exterior fabric a consistent base. Then I can add whatever heavier interfacing, foam, or fleece the product needs over that.
Ideally, of course, everything is bonded exactly where it's supposed to be. But heavier interfacings don't always cooperate perfectly. If there's a small area where the main layer isn't fused quite as thoroughly as the rest, having that interlining already bonded to the exterior fabric helps keep that inconsistency from showing through as easily.
If the separation is significant or visible, I'll go back and fix it. But I've learned not to chase absolute perfection in an invisible layer when it isn't affecting the finished product.
I cut first, then fuse
Another choice I've settled on is cutting my interfacing pieces before I fuse them to the fabric.
It takes longer. There's no getting around that.
It would certainly be faster to fuse a large piece of fabric and interfacing together and then cut my pattern pieces from the already-fused material. But cutting the interfacing individually lets me arrange those pieces more efficiently and create less waste.
When you're making products to sell, those little bits of material add up. I'm willing to spend some extra cutting time if it means getting more useful pieces out of what I've bought.
The real test is what happens after it cools
When I'm finished pressing, I'm looking for a smooth surface and a good bond without obvious bubbling, wrinkles, or loose areas. But I don't consider the job completely done just because everything looks good while it's still hot.
I let it cool and check it again. If something has lifted enough that it's going to affect the finished piece, I'll go back over it. If everything is holding well and the fabric looks the way it's supposed to look, I'm ready to move on.
After using fusible interfacing over and over, that's probably the biggest thing I've learned: there isn't one pressing technique that works perfectly for every combination of fabric and interfacing.
Pay attention to the material you're actually working with. Protect fabrics that don't like direct heat or pressure. Give stubborn interfacing a little more time. Check your work after it cools. And if the interfacing you've used a hundred times suddenly decides it doesn't want to stick?
Welcome to interfacing.
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