I looked and looked for a good tutorial on this and couldn't find one so I'm attempting this myself. Let me know what you think. First shore up the edge of the fabric so you have a nice clean edge.
I put the folded edge of the fabric at the top and the salvages at the bottom. Using your ruler, and rotary cutter, cut through only the top folded edge. Start at the bottom but not at the edge. Cut up from the bottom a little.
Ok, so I didn't do a great job of perfect measuring, but you get the point.
This is what your fabric should look like when you are done. Now open up your fabric so each end looks like this. You will then want to cut through every other joint.
The first strip on the right is from the other side. I moved over two slits and cut… then skipped a slit and cut the last one.
You should now have one continuous strip of fabric. The joints will look like this.
I cut a little closer to the edge. Don't cut too close or you might rip the fabric and then have to join it together either by sewing or tying.
So ends my first tutorial! Hope it helps someone out there in internet land!