I have been using a prototype as often as practical for school and it has performed admirably--when not failing. It took a few weeks to recognize and repair most of the weaknesses and has operated stress free for most of the semester. It's also survived a couple of semi-rigorous bike rides.
This tutorial is based on the bag I've been using, but with important changes that will improve durability. Also, this is the most basic design I've made. Version 2 can be easily customized to suit the needs of the builder.
Here are pictures of the model currently in use (v2.2) and the one made for this instructable. Version 2.2 has taken some abuse and has underwent many, many repairs.
Don't let the 19 steps daunt you--making a messenger bag from scratch can become complex. I've attempted to simplify it, despite the many steps.
Step 1: Gather Materials
1. Duct tape
---3 30yard rolls.
3. Cutting board.
5. Yard Stick.
I imagine any brand or color of duct tape will do. For this instructable and my previous bags, I used standard Scotch/3M brand tape. It is 1.88in wide, gray, and purchased at the local hardware store. For your first go at this, I suggest whatever is least expensive.
The scissors, cutting board and pins can be purchased from any sewing supply store. If you don't want to pay for a cutting board, it can be substituted for a flat sheet of corrugated card board that has linear dimensions more than 3ftx3ft. I haven't tried it this way, but it should work. Also the pins can be substituted for thumb tacks--you'll need at the very least 44.
If you sew, you probably have good scissors, a cutting board and pins readily available.
Please note: don't use your good scissors and pins to do this instructable*. They will become gunky from the duct tape's sticky substance and annoying to use later on. I suggest after using pins for the first run that you separate them from your other sewing pins. Use a less good pair of scissors if you can.
After cutting a few pieces of duct tape, your scissors will gunk up and cutting performance/quality will diminish greatly. It is worth the time to take a moment to clean the gunk off of the scissors so they can cut cleanly again.
The materials needed to construct the hardware:
1. Duct tape
2. Marker Flags
3. Tension Pins
6. Tin Snips
7. Sacrificial Ruler
8. Regular Ruler
This portion is optional! If you have hardware laying around, you can easily use those.. I don't recommend it though.
All materials can be bought at Home Depot, except for the ruler maybe.
Hardware includes a handle anchors, shoulder strap anchors, and buckles. As mentioned, you can salvage these from another, preferably useless, bag. I strongly suggest that you don't ruin a perfectly useful bag just to make a mostly useful bag. That would be silly.
Amounts of different materials will be discussed in the hardware portion (step 12).
After gathering materials to build the bag structure, you may move to the next step without fear of injury.
*As user Aggrieved points out, you can periodically clean the scissors or pins with eucalyptus oil or goo remover. Be careful when cleaning scissors with plastic parts, as goo could dissolve these parts.
Step 2: Understand the Plan
Simply, we will build layers of tape sheets that will form a flat shell which we will fold into a useful, bag-like shape.
The areas that comprise the panels of the bag are marked on the first picture. The outside border serves as an interface between the panels and also helps make a clean edge when finishing.
The second picture shows the layers we will be making. Although 3 are shown, there will be 5 in this tutorial. The other two are permutations on the other 3 and optional, though recommended.
Notice how layer 2 is only 10 widths wide rather than 11 widths wide for layer 1? This is how we get the border on the left and right sides of the sheet--layer 2 is offset by .94in on either side.
It seems simple.. and it is! In practice, though, there are annoying bits due to the nature of sticky back tape.
Now that you understand the project completely, we can proceed...
Step 3: Begin Layer 1
After components are gathered, find an open area free of wandering animals or children. Spread the cutting board/card board over a large, flat surface. Make the duct tape, pins and scissors handy.
Cut one 36in strip of duct tape. With the sticky side face up, pin a corner to the board. Make sure you will have enough room on either side to accommodate the full width of the sheet.
Pull opposite corner of the pinned corner taught and pin. Make sure the length of the tape as a straight as possible.
Finish pinning the other corners, and adjust geometry as necessary.
Repeat 6 more times. Try to minimize the gap between the lengths, of course keeping the length as straight as possible.
Layer one is not done--it still needs side panels, but we'll get back to finishing it in a few steps.
Step 4: Begin Layer 2
Cut a 35in length of duct tape and place about 1in offset of the first layer.
This operation takes practice, you'll find. I suggest you stand or sit perpendicular to the sheet of tape. After cutting the 35in piece of tape, use your right thumb and middle finger to stick to the corners on the right of the tape, doing likewise with your left hand.
After both sides are stuck securely to your two fingers, pull taught. Align the piece above where it needs to be placed and slowly lower, adjusting as necessary. Lower until the piece is attached to the first layer. If you make a mistake, try to minimize the amount of contact with the bottom layer and pull gently off then try again.
You may accidentally pull the first layer up while pulling up on a failed strip placement. If this happens, just re-seat the pins, while making sure that the strip of tape is still aligned.
Repeat 5 more times, and you're done with the first tricky part.
Step 5: Begin Layer 3
Cut 6 pieces of tape 11.25in long.
Using the same thumb/middle finger technique as before, place this layer perpendicular to the previous layers at the 'top' of the sheet.
These pieces should span the second layer, covering it completely.
Place all 6 pieces, then we can move onto finishing the first and second layer.
Step 6: Finish Layer 1 + Layer 2
Begin by cutting 4 more 11.25in strips of tape. Place two on either side.
Using the same pinning method as in layer 1, pin to the sides so that the top of tape is parallel with the middle of the last piece of layer 3 placed. Pin all 4 pieces that comprise your side panels, then move on.
Layer 2 is finished by cutting 4 11in strips of tape and placing them on top of the newly finished layer 1, except with ~1in offset.
If there is any confusion, I suggest you look at the diagram.
After the side panels are completed, you can move on to finish layer 3.
Step 7: Finish Layer 3
To finish it, we will need to cover the new side panels. This will take 5 19in strips of tape. (18.8in, if you can measure/cut that accurately). Again, this is only to cover layer 2, which may or may not be 19in wide.
The first picture shows how to eyeball the measurement. It turns out it's close enough to 19in where this wasn't necessary.
Place these butted against the previously placed strips of tape in layer 3.
Cut 7 more 11.25in pieces of tape and continue to place below the 19in lengths.
Layers 1-3 are now finished!
Continue with layer 4.
Step 8: Layer 4
Begin as you did with layer 3. Cut 6 11.25in strips of tape. Place sticky side down on top of layer 3.
Cut 7 more 11.25in pieces. Place sticky side down directly above the 7 non-covered 11.25in strips of layer 3.
After placing all 11.25in pieces of tape, cut 5 19in strips of tape and place as you did with the previous strips.
Step 9: Layer 5
It's similar to layer 2, except where the side panels are concerned. The side panel strips of tape in layer 5 only cover layer 2/3/4--try not to touch layer 1 with layer 5.
It's also easy... so go at it. The pictures don't capture how easy it happens to be. They also don't capture too much detail with the compression, but trust me, there are more differences between the pictures than placement of scissors.
At this point, you can unpin the sheet and admire your work (carefully placing the pins in a container while you're at it--no one like stepping on pins). Be careful to keep the outer border clean--it will form the basis of the bag structure and nicely finished edges.
Step 10: Fold the Sheet Into a Bag
First, trim all edges to be about 0.7in all around. That's an arbitrary number--just make sure that the outer edges are mostly consistent. Be sure to cut off any needle holes. You also need to cut a 45 degree slice where the sides fold in on the corner. The top-left one is labeled, but the other three need to be cut, as well.
After the edges are all trimmed, we can begin folding. We are going to mate sticky border to sticky border.
First, mate a side panels to the bottom. Then the front panel to the side panels.
If you mess up, that is OK. Try to limit contact of the sticky border until you are certain that is how you want it positioned. If you must retry, you can try pulling the connected pieces apart, then attempt to rejoin. If some of the sticky parts come of, that is OK too--just keep trying.
If you completely destroy the sticky part and are beginning to damage the fabric of the bag, then I suggest you trim the destroyed bit of Layer 1 and use additional tape to reinforce the seam. Any ugliness will be covered up in the next step (cleanup)
I'm beginning to think that this step is unnecessary, but I haven't had the time to test whether it is or not.
Step 11: Clean the Bag
I have detailed in this step what I believe to be the very minimum cleaning before moving onto the hardware.
There is no order to this step that needs to be followed--just tape the interface border to the bag, reinforce the inside seams and cover any other exposed seams. I also suggest covering all corners in the end.
If you haven't done so already, you can fold the border into the top panel and front flap.
Step 12: Gather Materials for the Hardware
Most parts can be bought at Home Depot. I was unable to find 5/16 x 1/2in tension pins there, but the other ones mentioned are sold, though quantities are limited. The marker flags come in packs of 100. You'll only need 2 for all the hardware in this instructable, at most, but I'm sure you can find a use for the remaining 98. Mc Master-Carr sells everything you will need (and probably a lot more you don't need).
For the handle you will need:
1. Duct tape
2. 4 5/16in x 1in Tension Pins
3. 1 Marker Flag
4. "Structural Bar" (see note just below list)
7. Tin Snips
8. Permanent marker
The "structural bar" (item #4) used in this bag is an aluminum ruler. You can use the free paint stirrers, other flat bits of metal or just about anything small, flat and rigid.
For the shoulder straps you need:
1. Duct tape
2. 4 5/16 x 2in Tension Pins
3. 1 Marker flag
4. All tools mentioned above.
For the front flap buckle, you will need:
1. Duct tape
2. 3 5/16 x 1in Tension pins.
3. 2 5/16 x 1/2in Tension pins.
4. 1 Marker flag
5. 2 or more #10 washers.
6. All tools mentioned above.
7. Cross-cut metal-working file. (optional)
...Or you can use some hook-and-loop fasteners (Velcro) to secure the front flap.
All the parts are very similar, so I detailed the bending of only one.
The pictures are more descriptive than I can be, so I suggest you examine them closely.
Once you've decided what you want to make, you can move forward, prepared.
Step 13: Make Handle Anchors And/or Shoulder Strap Anchors.
First, remove the flag part of the marker flag. You will be left with a bit of wire. From one end, measure ~0.25in and bend to 90 degrees, using pliers.
From the first bend, measure ~0.5in and bend at the mark another 90 degrees. Slide a tension pin onto the wire.
The next bend will be on the other side of the tension pin from the second bend. Make sure there is a small gap for the pin to roll freely. Bend another 90 degrees.
Measure another ~0.5in from the third bend, and bend another 90 degrees.
There will be a lot of extra wire, so from the last bend, measure about 0.5in and cut. There should be ~0.25in gap between the cut and the end where you began.
Slide another tension pin on the 0.5in end and pull the second bend so that the 0.25in end is above the open end of the tension pin, then push the end into the tension pin.
Using pliers, grasp opposite corners and compress into a trapezoid shape. Grasp the other opposite corners and compress back into a rectangle. All angles should be about 90 degrees.
Notes: You will need two of these anchors for the handle.
The process for the shoulder strap anchors is mostly the same, but the tension pins are 2in instead of 1in. You will need two shoulder strap anchors as well.
If you're not going to make the buckle, you can skip the next step. Otherwise, move on...
Step 14: Make the Buckle
The buckle requires 5/16in x 1/2in tension pins. I had to order these from McMaster-Carr because I wasn't able to find them locally. If you can't find them and don't want to order them specially, you can use a salvaged buckle or some Velcro.
The first picture shows the layout of the buckle, minus the clasping pins (I'll wager that there's a trade name for those that I know nothing about).
To make the clasping pins, measure ~0.25in from one end of a wire and bend 90 degrees. Measure another 0.25in and bend 90 degrees. The result should be a 'hook' shape. With pliers, close the hook to form a partial loop. There should be enough room inside the loop to fit another wire into it.
Trim so the total length is about 2in. They are easier to handle this way, and you will end up trimming it to fit soon. Make another, as you need two.
To start the buckle loop, measure 0.75in from one end of a wire and bend 90 degrees. Measure 0.5in from the first bend and bend.
Slide two 1in tension pins or one 2in tension pin onto the second bend. Add ~0.1in (the width of two marker flag wires) on the other side of the pins and bend. From the third bend, measure ~0.5in and bend. Trim the excess past 0.75in from the last bend.
On one side, slide a 0.5in tension pin onto the buckle loop, followed by a clasp pin. Do the same on the other side, making sure the clasping pins are oriented the same direction. Holding the parts in place, insert the 1in tension pin in the center and compress closed with the pliers.
Consider where the clasping pins lie on the tension pins carefully. Mark just above this point on the clasp pins. Make another mark ~0.25in above the previous.
Bend at the 'lower mark' slightly 'downward' and trim at the second mark. You can file down any points on the clasp pins now if you want or need to do so.
All of the hardware should be completed at this point. We will begin installing them in the next step!
Step 15: Make Handle
Start by folding 12in of duct tape in half lengthwise. Cut another 12in length of duct tape. Place the folded piece of duct tape such that ~1in of it is covering the top half of the unfolded tape. There should be 10 or so inches of completely exposed tape remaining.
Fold the second piece of tape in half lengthwise, which will cover the previous piece and create a 23in strap of duct tape 0.94in wide. Repeat this process until you reach about 5 ft of strap.
Coil the strap tightly so that it forms a flat handle. It should be as wide as your palm, at least.
Slide the anchors in and position on either side. Count how many loops were made and place the anchors finally in the middle loop.
Compress and tape closed with three pieces of tape ~2in long (picture 8). You are done with the handle, but it needs anchor straps.
To make the anchor straps, fold another segment of tape about 12in long in half. Cut another piece about the same length and place the previous piece on the top half of the tape (picture #9). Fold over (picture #10). Two of these 12in long, 0.94in wide straps will need to be made.
String these pieces into the handle and fold at the halfway point (picture #11).
With handle and anchors made, they can be installed... which is in the next step.
Step 16: Install Handle
They can be found easily due to the structure of the bag. Note that the top panel is two segments of tape deep? The center should be easily found. On either side, count 1.5 widths of tape and mark the point at the center.
From this point, measure 0.5in above and below the two points. The line between these two points must be cut.
After cutting, cut 1in segments of tape and cover the seams (pictures #3 & #4).
Slide the handle anchor straps into these slits. Turn the bag over and get the sacrificial ruler. It is too long and has to be trimmed, in this case. Mark the area to trim, and trim.
This part is important--see picture #8 for clarification. Place a segment of tape on an anchor strap that is in the center of the bag, centering the ruler over it, tape them together. Using another piece of tape, tape the other inside anchor strap to the ruler.
Now do likewise to the outside anchor straps until the lengths are covered in tape (picture #10). Entomb the strap/ruler assembly onto the top panel. Remember: you cannot use too much tape. Try to avoid getting tape on the places that are supposed to bend, though.
You now have a mostly functional handle that should be reasonably reliable...
...seriously, it should work quite well if executed properly.
With handle and anchors now handily anchored, you can proceed to install the shoulder strap anchors in the next step.
Step 17: Install Shoulder Strap Anchors
If you want to follow this guide, though, we start by making two short straps. You will employ a similar technique for the buckle straps and full shoulder strap.
First, cut two pieces of tape at least 10in long. Try to get them close in length, but overall length isn't very important.
Combine both pieces by mating both sticky sides together. Cut two more pieces of similar length and cover the seams.
We accomplish this by taking one piece of tape and cover it halfway with the piece previously combined. This is demonstrated in the second picture. Fold the piece of tape over to cover the seam, as is shown in the third picture, albeit not very well.
Repeat with another piece on the other side. You should have a strap of tape about 10in long and 4 pieces of tape thick.
Slide the shoulder strap anchor to the center and fold in half. Cut two pieces ~0.5in of tape and secure the strap and anchor in position. Place the anchor and strap on the bag by straddling the strap over one of the sides.
Center the strap, then tape to the bag. Remember I said that amount of tape and lengths are less important now? I was serious. You cannot use too much. You can easily use too little, though. The more surface area of duct tape that anchors the shoulder strap to the bag, the more reliable it will be.
I cut four ~9in pieces of tape and place two on the outside and two on the inside of the bag. Then I cut a piece about 20 inches long and threaded through the strap anchor so that half would be laid outside the bag and half the inside. I did this twice. Not only does it help secure the anchor, but it reinforces the side and makes it more rigid.
Repeat this step for the other side and you have two shoulder strap anchors ready to receive a shoulder strap.
Next we will install the buckle and have a functional bag, finally! (hopefully?)
Step 18: Install Buckle
To start off, we need two straps. One will hold the buckle to the bag and the other will hold the washers. Cut a 18in segment of tape and center the buckle onto it about 4in away from one end. Place the washers where the clasp pins lie.
Remove the buckle and place another segment of tape similar in length to your first piece. Finish by covering the seams as explained in the previous step.
Make another strap, without washers and about 8in long. Again, this was detailed in the previous step.
Fold this piece in half and mark the halfway point, if not obvious. Lay the buckle on the strap at the halfway mark and mark where the clasp pins lie (picture #3).
At the holes, cut ~0.25in on either side of the half mark. It should be at least as wide as the marker flag wire.
Thread the buckle into the strap, so that the pins go through the holes properly. Secure in place with 2 0.5in pieces of tape just below the buckle.
Place the bag on its back and rough the buckle in. One side of the buckle strap should go up the front panel, while the other should go towards the bottom panel (this detail should be obvious in picture #12).
Close the flap so it is in fully closed position. The very top of the tension pins should touch the brim of the flap.
Poke holes in the washer strap where the washers are and combine with the buckle. Ensure that the front flap is fully closed and that the buckle is where it should be when you pull on the strap. Pull taught and tape down, trimming any excess.
With the strap and buckle in their final positions, tape them down permanently. As before, there is no such thing as using too much tape.
Optional: You can make a loop of tape to hold the buckle down. I won't explain how, as it should be obvious with the pictures included.
You can also finish the buckle holes any way you prefer. Previously I used needle/thread, but I don't like the look very much.
You should have, at this point, a fully functional bag. You can make a shoulder strap if you have enough spare tape...
Step 19: Make and Install Shoulder Strap
This one is not easily adjusted, unfortunately. In fact, it's very basic, but gets the job done. I left making it more useful as an exercise for the maker. As with the shoulder strap and buckle straps, this will take the full width of duct tape.
Begin by cutting 2 ~1ft lengths of tape. Rather than placing directly on top of one another, place 6in offset, so that there is 6in of exposed on either side of the proto-strap. Cut another 1ft length of tape and cover the exposed sticky side with 6in of the new strip of tape. Continue this process until you reach your desired length. You will probably need between 4 and 6 feet depending on torso size and positioning.
For this bag, I made about 5.5ft, which was about 1ft too long.
Cover the seams, if desired, by cutting lengths of tape and attaching by aligning the center line on one strap to the side of the other. Fold over.
Cut a 12in segment of tape. Cover one end of the strap with 6in of tape and thread through one of the anchors. Rough in the strap, making sure the piece of tape is centered. Install the strap by laying the tape cleanly and using another piece of tape perpendicular to secure the loop (picture #9).
Rough in the other side. Instead of finishing, try the bag on for size. Depending on where you think it is comfortable, adjust the strap. Once you find the perfect length, finish that side.
You now have a functional messenger bag!
I've already come up with some changes I'd like to make, as well as some more... ambitious designs, but I'm curious to see what other people develop given this simple recipe.
If you make one using this how-to, I would be interested in seeing it.