This instructable details one way of making a simple, professional looking strap out of duct tape, featuring a strapping tape core and velcro. There are as many ways to do this project as there are pant legs, so be as creative as you want.
* Duct Tape
* Strapping Tape (optional)
* Velcro Patches (optional)
Step 1: Prepare Your Tape
Now, if you want your STRAP to be nice and durable, I suggest using...STRAPPING tape. Heh heh... Anyway, strapping tape is great, if a bit pricey (like $7 a roll). But if you already have some, it'll make a good core to wrap duct tape around. I cut my strip in half, and stuck the 2 halves together. All you need to do is make a tiny notch in the end, then rip it lengthwise.
So when you put your strapping tape pieces together, be patient or it will turn out badly. Now you'll need a piece of duct tape that's about 2" longer than the strapping tape.
Step 2: Assemble the Strap
Lay the strapping tape down on the sticky side of the duct tape. Try to center it as best as you can, but if it's crooked by a tiny amount it won't really affect how it looks in the end.
Now cut some slits so you can fold the end of the duct tape in over the end of the strapping tape. Then you can trim away the extra and fold the long sides of the duct tape in, one over the other. Be sure to trim off any fibers dangling out, so the tape won't fray.
If you get wrinkles, you can probably smash them down with a fingernail. If they're big, you may want to start over, but this is the inside of the strap so you won't ever see it anyway.
Step 3: Place the Velcro
Now put it around your leg, to figure out where you want the other part of the velcro. This part should be as long as possible, to maximize the adjustment range. Make sure the two velcro pads end up on opposite sides of the strap.
Don't get the velcro adhesive dirty, and press it on nice and hard.
Congratulations, you're done! Now put that thing on and go for a ride!