So you wanna make your own backpack. Then this is the instructable for you! I'll take you through some easy steps to make your own bag like the one pictured above.
In order to make the bag we're going to need a few things. I have an industrial sewing machine, but for home sewers I will make notes of the things which will be different than my bag. The main differences will be in the construction of the straps and the the choice of padding materials. Here is a list of materials:
1. sewing machine
2. thread (tex70 nylon bonded) tex50 for home sewers.
3. 1" spring clips
4. double sided tape (not the foam kind) or contact cement or spray adhesive
5. fabric (I use 1000D cordura but you can use anything dimensionally stable)
6. webbing 1" about 2 meters total (home sewers will use a lower density polypropylene webbing)
7. plastic strap adjusters
8. zipper about 1 meter and zipper pull
9.gross grain webbing
10. 3/4" foam* or 1/4" foam for home sewers approximately 20"×20"
11. xacto knife
13.lighter - for sealing ends of webbing once cut.
15.snapset - either the dies which come with the snaps or a hand plier style.
16.ruler - meter stick
18. chalk or pen for marking
Step 1: Design Your Bag
I will go into detail about designing patterns in an upcoming instructible for now I've included a pdf of the pattern for the bag below.
A quick note that all of the red lines in the pattern represent the center lines, they're for ease of use when lining up the bag in assembly.
Step 2: Cutting Fabric and Extra Pieces
If possible we're going to try and use as little fabric as possible for each bag. I've attached an image showing how I cut the pattern.
the following lengths are for the webbing:
1"×14" - 2 pieces for strap anchors
1"× 6" - 1 piece for handle
1" × 4" - 2 pieces for strap adjusters
1" × 24" - 1 piece for reinforcement
Zipper - # 10 - 32" long - I buy my zipper in bulk so I cut it to length, you can buy pre-made zippers with pulls at your local fabric supply store.
Step 3: Make the Straps
Realistically you can make the straps at any point in the process, I tend to make a bunch of straps at a time to have them ready for any upcoming projects.
MAKE SURE YOU BACK STITCH AT THE BEGINNING AND END OF ALL PERMANENT SEAMS!
Pre-step 1. fold and sew 3/8" hem on one short side of both pieces of strap fabric, this will be the finished edge where we will insert the strap adjuster.
Step 1. cut 2 foam pieces to 2"×14"
Step 2. place a piece of double sided tape lengthwise on each piece of foam.
Step 3. lay the fabric on top of the foam so the right side faces out and make sure the fabric extends past the middle most point of the foam. We're going to be stitching down the middle of the foam so we want to make sure the stitching will catch both pieces.
Step 4. wrap fabric around foam and roll over final edge 1/2"
Step 5. secure both ends with a spring clip.
Step 6. stitch down the center leaving about 1 inch at the end where the strap adjuster will go.
Step 7. pinch edges of bottom into trapezoid shape, insert strap adjuster and webbing and secure with spring clip.
Step 8. stitch around trapezoidal shape ensuring to stitch over the webbing several times. Make sure there is a good amount of webbing inside of the strap when you sew across it; minimum 1/2". Otherwise when you pull on the strap to adjust the length the webbing could fray and pull out as well.
Step 9 is optional. you can stitch closed the opposite end of the strap if you wish.
Step 4: Adding Zipper to Lid
The first step for the bag is to sew the zipper to the lid.
I add small pieces of fabric over the end of the zipper to leave a clean look. these are generally around 1" wide by 4 " long. Topstitch them over top of the zipper ends, you may want to turn the wheel by hand as you approach the teeth to make sure the needle enters between the teeth and doesn't come down on the plastic or metal as that could break the needle.
Once this you've done this initial step proceed with the following:
Step 1. Mark the center of the zipper lengthwise with a piece of chalk and line it up with the center mark on the lid making sure to put right sides together.
Step 2. add spring clips around the border of the lid effectively "pinning" the zipper to the top. I generally unzip the zipper because it's easier to manipulate the just the tape of the zipper around corners and other curves.
Step 3. Start stitching the zipper completing one full round
Step 4. Stich a second time around to reinforce the zipper. it's a high stress point so reinforcing it doesn't hurt.
Step 5. Turn the lid so that the right side is facing up. Beginning at one end top stitch the fabric close to the zipper. make sure the tape of the zipper is caught underneath of the top stitching, this will create a nice firm edge. It may be necessary to zip up the zipper in order to fold the tape around the bottom. Experiment with what works best for you and your machine.
I included a picture of the underside so you know what to look for.
That's it for the lid for now. Next on to the pockets for the front section.
Step 5: Pockets!
At this point in the process you get to do a little design work. I've included the basic pocket in the pattern and I'll show you here how to go about assembling it, but the sky really is the limit when it comes to what you can do with the pockets. in an upcoming instructable I'll show some different methods of making pockets and pockets shapes.
In this tutorial the front three pockets are made from a single piece of fabric 28"x10". The bag itself is only 24" so where do those extra inches go? the 2 side pockets will be 6.5" wide and the main pocket 11" wide. the extra 4" is for the depth of the center pocket. I'll explain how to gather the excess to create the depth.
Step 1. Bind the top edge of the pocket with gross grain ribbon or edging material. You can use a folder like the one picture above or using a low temperature setting on an iron, iron the ribbon in half, pin to the edge and then stitch. Realistically the ribbon can even be folded by hand if you have the patience. If you don't mind the pocket being shorter you could double roll the top and hem it there. I prefer to do this for fabrics that can be pressed with an iron like canvas.
Step 2. Place the pocket on top of the front and line up one of the edges of the pocket with the edge of the the front piece. Leave about 3/4" space from the bottom of the front piece. With some chalk mark a verticle line onto the pocket 6.5" parallel to the edge of the front piece, making sure the line extends onto the front piece above and below the pocket. Do the same on the opposite side. These lines will be your stitching guide which will divide the single piece of fabric into 3 pockets.
Step 3. Line up the first edge and stitch down the outside edge of the pocket and down the chalk line.** Repeat with the opposite side.
** when stitching the edge seam use a 1/4" allowance. This seam is only a fail-safe seam for the pocket it will be covered by the side seam when we stitch the back to the front.
Step 4. You should now be left with excess fabric in the center between the 2 chalk marks. you can now pinch the bottom corner so the that fabric overlaps on itself creating an accordion type fold. Secure with a spring clip and do the same to the top edge making sure they run parallel. Repeat on the opposite side. The pocket should now be relatively taught against the front piece secure by the 4 spring clips.
Step 5. Sew along the bottom off all the pockets leaving a 3/8" seam allowance.
And there you have it. 3 pockets in one.
Now take the piece of 24" long webbing and sew in about 3/8" from the bottom of the front piece. it should cover the raw edge of the pocket. Alternatively you can hem the bottom of the pocket before sewing onto the front and skip this step, but the webbing adds rigidity to the bag helping it to keep its shape.
The last step is to patch the lid of the large pocket onto the front piece. I generally add snaps at this point as its easier to do then when the bag is fully assembled.
Step 6. Bind the edges of the lid. I use a binder which makes this go very quickly, but you can roll the edge binding by hand as well. The binder picture costs about $35 from a sewing supply store and has saved me ages of time. Not to mention with a little practice the stitching comes out nearly perfect every time. The screw holes that are normally used to secure the binder to the machine are stripped out on mine so I use a few pieces of packing tape.
Step 7. Line up the lid and patch it on. I generally heat the ends of the gross grain and tuck them under the lid as I sew it on.
Step 6: Adding the Lid to the Front
This step is pretty straight forward. Line up the centers of the zipper and the front. Zip or unzip the zippers as require to manipulate them to attach the lid to the front. Do not topstitch afterwards.
Step 7: Assembling the Back
Now that the front's done you'll want to assemble the back. This is where the bag starts to really come together and the end is very near.
Step 1. Cut a piece of foam 6.5"×18.5" *** If you have a home machine it would be better to cut the foam lengthwise down the middle into two 3"x18" pieces. When you place them on the back piece to stitch leave a 1/2" gap in between the two pieces, this should be large enough for the foot of you machine to fit into. This minimizes the amount of material you sew through to just 2 layers which your machine should be able to handle.
Step 2. Mark the centers of the fabric and foam vertically. Apply several pieces of double-sided tape or glue to all the pieces. Align the centers and stick together. Keep in mind the foam padding will go on the inside of the bag. You can apply spray glue to the fabric so that it sticks to the foam evenly. Make sure the pieces have adhered well before stitching. Uncured glues and adhesives can gum up sewing machine mechanisms. I tend to wait about 15-30 minutes depending on what the cure time of the adhesive is. It will be listed on the label.
Step 3. Stitch down the center line of the back. Then stitch across the top and bottom. Finally stitch along the sides.
Step 4. Take 2 pieces of ribbon or webbing and stitch them over the raw edges of the fabric. Alternatively you can fold the edges and stitch down.
Step 5. Add an optional laptop pocket overtop of the foam padding.
Step 6. Assemble the strap anchors by hemming the broad edge of the triangle, folding the fabric in half inserting the webbing and stitching along the edges. Take care to backstitch over top of the webbing a few times to secure it.
Step 7. Attach the straps and hanger webbing using the centerline of stitching as a reference for placement.
Step 8. Attach the strap anchors.
Get ready to put the bag together.
Step 8: Give It Some Shape.
Now we're going to give that bag some shape!
Step 1. Pinch the corners of the bag and sew a 3/8" seam to close them up. I like to sew an additional seam at 1/4" for some reinforcement.
Step 2. Bind the raw edges with gross grain, trim and seal the edge
Now the big moment. time to put the back to the front and make a bag a bag.
Step 3. Take some spring clips and match the center top of the bag and then match the bottom. Add spring clips around the perimeter as you see fit.
Step 4. Start sewing. Remember to leave the zipper at least part way open, otherwise you will be unable to turn the bag right side out. I tend to sew a 1/4" seam around to begin with and then I sew a 3/8" seam afterwards. Make sure to reinforce in the corners as these are generally the weak spots. I like to sew down one side, then then the other and after that I sew the bottom and the top.
Step 5. Cut the excess material around the corners to a rounded shape being careful not to nick the stitches.
Step 6. Using a 1- 1 1/2" webbing or gross grain tape bind around the unfinished edges of the interior. This will add extra structure and leave a nice finished edge.
Step 9: Finishing
If you've come this far congratulations the light at the end of the tunnel is approaching.
After the inside of the bag is bound flip it right side out and have a look at the seams and once you've verified that everything looks good find those snaps we installed earlier.
I've found probably the most foolproof method of placing the receivers for the snaps is to take a piece of chalk and rub it on the bottom of the installed snaps. Then proceed to press the snaps onto the pocket. They should leave 2 distinct marks on the pocket. From there I generally pierce about 1/2 directly above those marks to install the receiver. This just simply because once the pocket has things in it you want a little room for give for the snaps.
Now step back, give yourself a well deserved pat on the back and enjoy your new bag.