Working with Bias Binding
If you pay attention to character designs in anime, games, and other animated media, you’ll probably notice a lot of bold, stark detailing at edges and seams. It’s a detail that tends to read well even in very simple art styles, and helps to create graphic, memorable looks. Depending on where and how these hard edges are depicted, you can replicate them on your costumes with applied trims like ribbon, braid, and cord; with piping, or with bias binding. Today we’re going to take a look at bias binding, which is the go-to way to create pieces with contrasting borders or outlines.
Bias binding or bias tape is most often used as an edge finish: on hems, necklines, lapels, armholes, and elsewhere. It’s especially good for curved lines and edges, as it can be shaped more easily than most ribbons or other trims, and also makes nice crisp corners. It’s almost always used to finish the upper and/or lower edges of a corset, as it allows you to finish two or more layers of fabric at the same time without any hem allowance or extra bulk.
Purchased bias tape can be a great time-saver, and is usually treated to be stable and easy to work with, so it’s a good bet if you’re not super familiar with sewing bindings. It’s most commonly available in a plain cotton/polyester blend fabric, with a reasonably large range of colors. Decorative tapes including prints, metallic fabrics, and embellished tapes are sometimes available as well, so keep an eye out in case there’s something that will work for your project. If you find a particularly lovely ribbon or tape trim, you can sometimes use it in place of bias, though most ribbons are difficult to shape around curves, so it’s best to reserve this for simple, straight shapes. Very thin leather strips are also sometimes used for binding, and have the advantage of being fairly flexible while needing no edge finishing.
All that said, if you need your binding to be a particular width, or you want an exact match to your fabric, the best option is often to make your own.
Making Your Own Bias Tape
To make your own bias binding, start by choosing a suitable fabric. The simplest choice is to use the same fabric you’re using for the main garment, so you’ll be absolutely sure of a color match. In some cases, you might want to use the back side of the main fabric to get a bit of contrast. If your main fabric is especially thick or dense, like wool coating or denim, you may want to choose a lighter fabric for the binding so that the extra layers won’t be too bulky. Lightweight satin and sateen are great for this, and for anywhere you want a contrasting binding, as the fabric’s luster will catch the light and make the details stand out beautifully. Just keep in mind that it’s best to choose something relatively easy to handle, or you’ll be in for a lot of basting to make all the layers behave. Also, be careful of fabrics that have an unbalanced weave – that is, with threads that are much denser or heavier in one direction than in the other – as bias tapes made with these fabrics can be more difficult to work with.
Cutting your binding on the bias serves two purposes: to give the fabric more stretch and flexibility, allowing it to be shaped around curves, and to prevent fraying so the strips are easier to work with. The bias grain runs at a 45º angle to the warp and weft. Measure the available fabric width and the same distance along the fabric selvage, and draw a diagonal line connecting the two. Then, you can measure from that line to mark the necessary width for your strips. If you need a lot of bias, you may want to check out the continuous bias technique as described by Liesl Gibson here. If you just need a few strips, cutting them individually will give you a cleaner tape with fewer seams.
For bias tape that will be applied like a flat trim, start with strips that are twice as wide as the finished width. For bias tape that will be used for an edge finish, the strips should be four times the finished width. Some fabrics, especially those that are loosely woven or have a slinky, drapey hand, may need to be cut a little wider than this as bias strips will narrow when stretched. You will also need extra width if binding multiple layers of fabric, or fabric that is particularly thick.
While you can fold and press your bias tape by hand, bias tape maker tools can speed up the process and give you a more consistent fold. To use the tool, insert the fabric strip through the wide end and stick a pin in the top slot to pull it through to the other side. Pin the (now folded) end to your ironing board, then pull the tool slowly and steadily along the length of your strip, pressing the folds in place with your iron as you go. If you will be sewing the bias tape on flat as a trim, you’re all set at this point. If you will be using it as an edge binding, you may wish to fold it in half and press in the edge crease as well.
Applying Bias Binding
There are at least three main ways to apply bias binding, depending on whether you’re okay with visible stitching and how much you like hand sewing.
Method 1: topstitched
This method is hard to screw up, and looks neat and professional as long as you’re able to keep the stitching fairly straight. (If your machine has an edgestitching foot, it’s your best friend here.) Open out one side of the bias tape and align it on the inside of your edge. Stitch in the fold, then wrap the tape around the edge to the outside and stitch close to the folded edge with a plain or decorative stitch. The exact placement of the stitching on the inside will depend on how accurately you fold and stitch, and may be slightly higher or lower than shown.
Method 2: stitch-in-the-ditch
This method results in less visible stitching on the outside, but may require hand basting to get a neat finish on the inside. Fold your bias tape so that the inside fold is slightly longer than the outside fold. Fold out the shorter edge and sew in the crease to the outside of your garment, right sides together. Wrap the longer edge to the inside and press well. Baste if necessary to hold the inner edge firmly in place. (I sometimes think I can get away with not basting this, and then end up kicking myself and having to redo it. Save yourself the trouble and baste the first time.) Stitch from the right side, right in the little depression where the binding meets the main fabric. (the “ditch” of the seam). Make sure you’ve caught the inside edge of the binding along its entire length.
Method 3: hand stitch
This method brings you closest to a truly invisible stitch on both inside and outside, although some fabrics may tend to show dimples from the hand stitching. It also gives you the most control when you’re sewing tricky shapes, or working with a difficult fabric. The downside is that it requires precise hand sewing skills and can take quite a bit longer than other methods. Open out the bias tape and sew it to the outside of your edge, right sides together. Wrap to the inside, press well, and secure with small hand stitches as shown. Make sure to keep your stitches between the fabric layers so they aren’t visible on the outside.
Curves and Corners
The wider your bias tape, and the softer your bias fabric, the more difficult it will be to shape evenly around curves. To prevent the tape from narrowing when you shape it around curves, make sure that your the tape is long enough to cover the full length without stretching. For very tight curves, you may want to shape the bias with steam on the ironing board before you apply it. After sewing, press carefully with as much steam as your fabric allows to get a nice flat finish.
To neatly shape bias tape and other flat trims around corners, you’ll need to sew in a miter.
When stitching the first side of the bias tape, sew the first side of the corner exactly to the inside corner of the binding. Stop and lift your needle, then fold the tape as shown before aligning the next edge. Continue sewing from the same point. Fold the tape around the edge, making sure the miter is arranged neatly on the reverse side, then stitch it all down using your favorite of the above methods.
To sew an inside corner, first staystitch about a needle width into the seam allowance from your stitching line and clip into the corner. Line the bias tape up with the first edge, and place it in the sewing machine tape side down so you can see the staystitching. Stitch to the corner and stop with the needle down, then lift the foot and pivot the next side of the angle forward to align with the tape, smoothing the excess fabric back out of the way. Sew the rest of the way, then lay the corner flat, fold the binding around the edge, and use a pin to arrange the fold before stitching it down.