Tuesday, April 20, 2010

Bias Tape 101: a tutorial

While I was working on the tutorial for the reversible sundress, I realized the pictures and instructions for the bias tape was becoming a tutorial all it's own. So here we go - Bias Tape 101.

A lot of this information is going to be very basic with loads of pictures, because we all learn better that way, right?

First of all, what is the bias of a fabric? Very simply, the bias just refers to the direction of the fabric at a 45 degree angle, diagonally, across the fabric. So if you took a square piece of fabric and drew a line from the top left corner to the bottom right corner that line would be across the bias of the fabric.

Let's do a little object lesson. Go grab a piece of cotton fabric. Go ahead, I'll wait....Got it? Okay, now give it a little tug holding your hands vertical. Not much give, right? Now try it holding your hands horizontal. A little more, but still not too stretchy. Now try to stretch it holding your hands on the corners and tugging diagonally. Nice and stretchy, right? THAT is the bias of the fabric.

Bias tape is a thin strip of fabric cut on the bias and folded in a particular way. More on the folding later. It's used mainly for finishing hems, armholes and can be used as the edging in blankets and a multitude of other things. Because of it's stretchy nature, it's much better suited for manipulating it around curves. Fabric cut along the grainline usually doesn't have as much flexibility.

Before I get any further, let me mention that you can buy bias tape - and if you're using it for the first time, I'd recommend that. It comes in a variety of colors and sizes and you can find it pretty much anywhere. But if you have a pair of scissors and an iron, you can make bias tape very easily.

Okay, let's get started. Pretend I'm cutting this fabric on the bias. Confession: I hate, hate, hate cutting fabric on a bias. It wastes so much fabric and you have to measure pretty precisely to get a nice even cut. So if my fabric has a decent amount of give along the grainline, I just go ahead and cut it this way. It just so happens that this particular cotton was pretty stretchy along the grainline. If you're using the tape to close a sharp curve, you will want to actually cut on the bias. We'll just call my tape grainline tape...ahem.

I cut my strips 2 inches wide - we'll be making double fold bias tape, so we'll end up with 1/2 inch finished tape. Your finished tape will be 1/4 of your original strip width, so if you're looking for 1 inch tape, you'd need to cut your fabric strip 4 inches wide. Make sense? Okay, moving right along...Cut your strip or strips as long as you need them for your project.

Okay, now this is really, really important. Take your strip and lay it right side down on your ironing board. Fold it in half leaving about a 1/16 inch overlap on one side. You can measure if you want, I just eyeball it.

Press to set the fold, making sure you keep your tiny overlap in place.

Now open up your newly creased bias tape and fold the outside edges in towards the crease you just made.

Because your first crease line is slightly off center, You should have one fold that is slightly longer than the other, like the photo below. Now press those folds in place, moving your hands and folding as you work your way down the strip:

Now fold the strip in half, right on the original crease line you made- you should have a little overlap where the edges don't quite meet. That's perfect, and you'll see why in a minute. Press, press, and press some more. Make those creases nice and defined.

Your bias (ummm, grainline..) tape is ready to be used!

Head to your sewing area. For illustration purposes, I cut two small scraps of fabric on a gentle curve.

Open up your tape.

Okay, now we are going to sandwich the raw edges of that curve inside this bias tape.

So open up your tape and place the wrong side of your fabric on top of the longer fold.

Fold the short fold side of your tape over, sandwiching your raw edges inside the tape.

Pin in place. I can't emphasis pinning enough. Normally, I don't pin if I don't have too, I'm a lazy seamstress, but bias tape - especially along a curve - really needs to be pinned!

Work your way along your raw edges, opening your tape and making sure your edges are pushed as close to the inner crease of the tape as possible and pinning as you go.

Once your tape is all pinned, head to your machine!
Start stitching as close to the edge as you comfortably can.
Here you can see how close I came to my edge:

Now remember, because that longer fold is on the opposite side, we're easily catching it with these stitches. If the folds were exactly the same length, you *might* be catching it, but you'd probably end up with some missed spots. That teeny little overlap is your "wiggle room" and gives you a perfectly finished seam on both sides of your garment:

Easy peasy, right?

There are a lot of ways to sew bias tape - so I'm not claiming to have the perfect method, but this is what works for me, so I thought I'd share.

Did I leave something out? Have questions? Am I speaking gibberish? Leave me a comment or email me!

Next up: The perfect project to put your new bias tape skills to the test, The Reversible Sundress!



  1. Great tute! Very clear...I think it'll be helpful to A LOT of people!

  2. Makes perfect sense to me! Great job!

  3. I didn't use a tute for the diaper bag. I just winged it! But I'm thinking about doing my own tute when I make the next one. I've never done one before though so I'm kind of nervous! I'm afraid I do everything "wrong" and none of it will make sense! Haha