You can buy bias tape in any retail craftyplace for $2 and change (plus gas). You can also order bias tape online, paying a ridiculous shipping cost (or waiting FOREVER for it to arrive). However, commercial bias tape is typically solid in color, comes in 3 yd. packages, and is sometimes difficult to coordinate with your sewing project. With $3 in fabric*, some thread, and a couple hours, you can make continuous miles† of your very own.
* full retail. I picked up this piece for $0.72, including tax. It can be done for free if you have discarded clothing or sheets you are willing to cut into.
† ok, yards, but an easy 4-5x more!
Step 1: Supplies
woven fabric, laundered (the piece I am working with is cotton, 25 in. L x 44 in. W.)
iron + ironing board
needle + thread -OR- sewing machine + thread
ruler -OR- measuring tape + a straight edge
washable marker (rinses out) -OR- chalk, depending on light or dark fabric
cutting mat, rotary cutter, poster board for strip template (not pictured), hat pin (for wider bias tape)
Step 2: Fabric Prep
Selvedge is the factory produced edge which keeps the edges from fraying. In my experience, selvedge can behave differently from the body of the fabric when laundered (shrinking, going wonky). I don't know how or if it would affect bias tape, but I'm a big fan of snip-and-rip, so...
Iron your fabric.
Step 3: Fold, Cut, & Piece
You will be making a parallelogram with your fabric rectangle.
Fold one end of the fabric so that the end aligns with a side edge, forming a triangle*.
Pin along the fold to secure positioning and press.
Unfold your fabric and cut along the crease.
Move the triangular piece down to opposite end, without turning.
Flip the triangle over, right sides facing.
Line up the edges, and pin together.
Sew this seam with 1/4 in. allowance (typically the distance between the needle and the edge of the presser foot, if using a machine).
Press the seam to one side.
* If you've ever done origami or made a square from a rectangular piece of paper, this fold will be familiar.
Step 4: Marking & Cutting Strips
Flip fabric over to the wrong side.
Starting at one angled edge, using your washable marker, mark strips 1-3/4 to 2x wider than desired finished width for single fold tape or 3-1/2 to 4x wider for double fold tape.
I am making 1 in. single fold tape (which can also be pressed into 1/2 in. double fold), so I marked my strips at 2 in., resulting in 14 strips, which will make ~14 yds., and some remnant. Had I marked at 1-3/4 in., I would have gotten 16, possibly 17, strips.
To make measuring and marking easier, I cut a 2 in. W template from a piece of poster board.
Step 5: Sewing Strips Together
Place right sides together, with points sticking out approximately 1/4 in. on either side.
Sew strips together with 1/4 in. seam allowance.
Clip off points.
Continue sewing strips together as above until you have one looong strip of fabric.
Press all seams open.
Step 6: Prepping to Press
Measure out the desired width of your tape and run pin through the ironing board cover, cross your desired width, and push pin back through the cover. Your pin should be at a right angle to the length of your ironing board.
Trim leading end into a center point.
Step 7: Pressing Into Tape
With the wrong side of the fabric facing you, thread the point under the pin.
Fold the edges of the strip inward, meeting in the middle.
Gently pull a couple inches of fabric under the pin and press. Continue to pull, release the tension on the fabric, then press. I generally pull ~4 in. at a time so I can just set the iron on top of the fabric and press without moving the iron.
To make double fold bias tape, after pressing all of your strip into single fold, fold the tape in half just shy (1-2 mm) of aligning the edges, and press.
Et voila, bias tape :)
Step 8: Tips
To keep the tape from running all over the house while pressing (ie. becoming a cat toy), I like to wrap it around a piece of folded paper (or cardboard) as I progress.
Somewhere in pressing your single fold, the fabric will probably get squirrelly on you, trying to fold asymmetrically. To remedy this, go a couple inches down on the unpressed side, realign the edges, pull the tape through, and press.
Make something amazing!