I looked at photos and descriptions on:
http://craftbits.com/project/make-your-own-kids-backpack/ - this is the same style backpack, with a flap closure, outer pocket and adjustable straps. I think there are some variations in the method, but the end result is the same.
http://www.made-by-rae.com/2009/03/finally-here-toddler-backpack-pattern/ - this is a completely different style of backpack, with a top zipper and piping, but very importantly I got an idea of the dimensions to work with from this page.
This is a very simple backpack, with a flap closure, one external pocket, and adjustable webbing straps. I used a mixture of fabrics, thread, iron-on light-weight pellon, D-rings and webbing.
I used the pellon on the flap, the outer pocket, the sides and the base. I didn't use it on the back or front pieces.
For the pocket: cut two pieces of fabric 10 inches wide and 6 inches high. Iron a piece of pellon onto one of the fabric pieces. I cut my pellon slightly smaller so it doesn't bulk up the seams and add some light quilting to hold it in place, but sewer's choice. Seam the two pieces of fabric together along one long side. Set aside for a moment.
For the flap: cut two pieces 10 inches square. I had a left-over block from a quilt that I wanted to use, so I edged it to fit. Seam the two pieces together on three sides. Set aside for a moment.
For the front and back outer: cut two pieces 10 inches wide and 12 inches high. Set one aside (this is the back). Pin the pocket to the right-side of the other piece. Line up the raw edges of the pocket with the raw edges of the front piece. Pin or baste in place.
For the sides: cut two pieces 12 inches high and 4 inches wide. Iron on pellon to both (and quilt in place). Sew the sides to the front, making sure the sides of the pocket are caught in the seam. Stop the seam short of the bottom of the side by the width of your seam. That is, if using a 1/4 inch seam, stop 1/4 inch before the end; if using a 1/2 inch seam stop 1/2 inch before the end. I still haven't worked out how to do this on the overlocker (I overlock/serge all bags for strength), so I unpicked.
For the base: cut one piece 10 inches long by 3 inches wide. Iron on pellon (and quilt). Sew to the bottom edge of the front piece, again making sure the pocket is included in the seam, and stopping a seam width short of the ends.
For the back:
For the lower straps: cut two pieces of webbing 3 inches long. Thread two D-rings on to each length. Pin the ends to the sides of the back piece about 2 inches up from the bottom edge.
Sew the sides (sewn to the front piece) to the back piece, ensuring the straps are included in the seam. be careful sewing over the bulk of the straps. As for the front, stop short of the end of bottom edge. Sew the base piece onto the bottom edge of the back piece.
Sew the bottom edge of the side to the end of the base piece of each side (this is why you stop short of the edges).
(Alternatively, you could cut the sides and bottom as a single strip, and sew them to the sides and bottom in a single seam, pivoting at the corners, to both the front and back pieces.)
For the top:
For the handle: Cut another piece about 5 inches. Pin each end either side of the centre line of the top edge of the back piece.
For the top straps: Cut two lengths of 25 inches pin about 2 inches in from the edges on the top edge of the back piece.
Pin the flap sewn earlier to the top edge. Check everything's pinned to turn out to the right side - straps inside the bag aren't very useful.
Sew the top edge of the bag.
For the lining: cut two pieces, 12 inches high by 14 inches wide. Sew the side (12 inch) seams. Sew the bottom seam in from each side, leaving a gap in the middle about 6 inches wide. So the lining fits inside the bag, the corners are 'boxed'. This might be tricky to explain without diagrams: Fold the bottom corners of the bag so the side seam and bottom seam are lined up, on top of each other. This forms a point. With your ruler perpendicular to the seams, rule a line where the folds are 4 inches apart. See http://www.sew4home.com/tips-resources/sewing-tips-tricks/how-box-corners for some lovely photos and explanation of boxing corners.
Sew the lining to the outer bag along the top edge. I always have to check and recheck I've put them together the right way for it work, but I think it was: Lining is inside out, outer is right-way out. Put the bag into the lining - make sure the flap and straps at the top are on the correct side. Turn the bag out through the bottom of the lining.
Top stitching: I top stitched a couple of seams as I went - the pocket top edge, the side seams, the flap, the top edge of bag and lining.
|Back of bag showing straps and handle. The front is the same green fabric.|
|Bag open to show the grey lining and front pocket.|
|Bag hanging. I added fabric tabs on the ends of the cotton webbing to stop it fraying.|