This year I have 4 kids heading off to school. I decided the make them backpacks and they all think that idea is cool. Here is a quick tutorial to show you how it is done. I am trying not to bog it down with too much description and too many detailed measurements to you can take the idea and make it your own.
heavy fabric for the pack
coordinating fabric for the pocket and strap casings
about 3yds of heavy cord
1. Cut out your pack. You need 2 pieces the size you want your pack plus seam allowances. This one is 14x19. I found though that I didn't leave enough room for the bag to close without squashing her folder. I would add another 3 inches to the height to accommodate that. You can test that with what you need to put in yours and measure that way.
2. Make a pocket. Take a scrap of the bag material and line it with a bright fabric you want to use. Sew around the edges. Turn and press. Leave your opening where you turned on the bottom. My pocket is about 9"x9"
3. Stitch the pocket onto the outside of your rucksack near the bottom end. Stitch along the sides and the bottom. Re-enforce at the top to make it sturdy.
4. You can make a flap for your pocket. Just be sure it is a little wider than the pocket. I lined this flap as well. Stitched around it. Turned and pressed it. I then top stitched the edges to keep them neat. You can add a button, snap, or Velcro if you want.
5. Now you need to add a casing at the top for the straps. I cut a strip of fabric 3" by the width of my bag. I then folded under the sides and top stitched them to make a clean edge. I folded the casing strips in half right side out and stitched them to the top of my bag. The edges of the casing them came right where my seam allowance for the bag will be. (they are stitched to the right side of the bag fabric.
6. Now put the front and back pieces right sides together and stitch the sides and bottom. Be sure to re-enforce the top seam. Turn and press your bag. Your casing edges should now meet.
7. Add the grommets to the bottom corners of your bag. You can use a press, or the kits you can get at the store. You can also leave the bottom of the bag open, string the straps through the casing then stick the ends into the bottom of the bag and sew them in with the bottom seam. You could even add loops to the side to attache them with.
8. Now string your straps. You need 2 straps long enough to go from the corner of the bag, up through the casings and back down to the same corner on each side of the bag. For a little back back the was about 1 yd each. It is easier to make it a little long and cut it down if you need to.
Secure the ties through the grommet hole with a sturdy knot.
Now you are done!