recycled banner golden mean messenger bags

last summer L. and i wanted to steal one of those orange banners that announced the minimal future exhibition at the MOCA with a richard serra piece to make a bag out of it a la freitag. imagine that, a richard serra bag. we even profiled a few lightposts that we could climb to get the material but never did it. L. bough some vinyl downtown and we did some things with it and decided that we liked the material so the idea hanged on. a few weeks ago i was riding home from work and after stopping to check two bicycle shop dumpsters (you know, they thrash all kinds of usable stuff) i went by certain banner printing place to check if they were throwing any banners away and surprise! their dumpsters were full of material. there were people working that day and the shops were open to the alley but i grabbed a big piece of vinyl and rolled away in my skinny bike. i must have looked like a cat grabbing a big chunk of cheese. one block away i folded the thing and strapped it to my bag.

so it was time to make a messenger bag. once confronted with the design issue i looked around in the web but couldn't find anything that specific. well, a lot of bags i'd like to have and some features worth trying. in one visit to the kitchen Jimmy showed me his bags and the things he liked about them, one from chrome and one from P.A.C designs. i definitely like those chromes too. i drew a crude sketch of the chrome with a sharpie on a postal envelope i found and stuffed it in my pocket. then, that night, i took a sketch book and a pencil and an internet enabled computer and drew a first proposal for the pattern. i wanted to use the golden ratio (if you don't know about it check out this introduction) in the design so i watched this animation i like a lot about the fibonacci sequence a couple of times and visited a couple of sites about the golden ratio. you know, the thing is everywhere, body, art, nature, literature, corporate logos. so, i thought, messenger bags, why not? there is no guarantee that something based on the "divine proportion" is going to be pleasing to the eye, or magically entwined with the nature of the cosmos. but for me it served as a starting point. an interesting starting point. i began with a simple 3x5 rectangle (any rectangle built with consecutive numbers of the fibonacci sequence approximates a golden rectangle) that would be the shape of the bag when closed. to see it open, i made an equal rectangle on top. the location of pockets and flaps was determined by the unit (1). and hence the central pocket would be a golden rectangle as well:

this first sketch looked rather square to me so i traced the larger side of a triangle with sides 1 and 2 in the lower corners of my original rectangle and that rendered the second sketch:

and happy with this one i went on to make a prototype with some of the stuff i found days before. some kind of mesh vinyl very easy to sew. this is the first prototype:







and it looked and felt good so i went on to make a full featured bigger version with that shape. the straps and small plastic buckles came from shopping carts. you know, L.A. is full of orphan shopping carts, they appear in every corner in every possible sad state. they are to L.A. what umbrellas are to New York. so, yes, i took those straps and buckles in a gesture that is to me like picking up sea shells at the beach. the city is in many ways like the sea, and so it gives a lot. i took the big buckle from a suitcase in certain chain store. i bought the velcro and found the foam for the shoulder strap in the thrash. when i sewed the velcro on the front flap the stitches were visible so i decided to sew the clear vinyl on top. i think it adds some appeal and the possibility to customize the bag with anything you want to put there. to start with i put some little tarot cards i had, including the one that i'm planning to use as a logo. the border of the flap is made out of a bicycle tube.














when the bag was ready i took it for a test ride during my daily commute to work. first disadvantage: the material doesn't breath so your back can get wet. not many messenger bags are made with breathable materials and this happens very often. but i'm thinking about using a different material in the back to ensure certain transpiration. someone suggested to put some detachable part that you can wash anytime, i might try that but i don't know how good is velcro on your back, or if the hardcore cyclist ever thought about washing his messenger bag. i also took it to december's midnight ride and received a lot of encouraging commentaries (thanks a lot people).

this one handles o.k. with a big load but i wasn't happy with the shape yet. i think the stabilizing strap is too high and the shoulder strap is a little stiff. my next attempt was a golden rectangle folded in half:

it renders a big big bag that covers your whole back. it is very deep and the flap has a lot of surface. i only made one prototype but i like it. it closes well even without velcro and has a lot of room, but it is a little square and i don't think it would make a good all-around bag.












then i made some drawings of the way this kind of bag is positioned in someone's back and it occurred to me that i should use the shape were the golden ratio appears most naturally: a pentagram. just to think about the history of this shape can make your head spin. from Pythagoras to Marilyn Manson. but on the other side, it is like the play dough of shapes. you can make so many things with it and yet it retains its properties. so i drew the basic shape of the bag using a pentagram:

a very easy way to determine the length of the sides is to use three consecutive numbers of the fibonacci sequence. first you choose the total length of the bag (a) and then the numbers before that one are the lengths of (b) and (c) in the illustration. the height is calculated using the Pythagorean theorem : h² + (c/2)² = b² in this case. (it sounds fancy but i bet you learned this in highschool).

so if you want a 55cm long bag, the length of (b) will be 34cm and (c) will be 21cm. the height would be 32.34cm:

i used a fibonacci calculator to find the approximated numbers of my bag. i wanted a 48cm bag so this were the three consecutive numbers which i roughly converted to centimeters :

... 1836311903 - 2971215073 - 4807526976 ...

the figures above illustrate the measures but the actual pattern i used looks like the following because you have to add the botton and the sides of the bag:

or even like this if you want to cut the whole thing in one piece:

and here is the first bag i made with this pattern:












i'm still working on the way the strap is attached to the bag. in all the other bags it was sewed on but in this one i decided to try a different way so i sewed just the "D-rings" to the bag (like the one you can see in the pic from the side) and the strap is attached to them. i'm not totally convinced about this yet but i like the general shape. for the strap i'd love to get my hands on some car seatbelts. the central pocket was made folding a piece of material that has the shape of the orange part in the picture above so it goes according to the other lines of the design. the interior is made of a lighter fabric (a flag actually). and the border of the flap is made out of bicycle tube. that tube is one of the hardest things to sew on but i've discovered some tricks along the way. it's also the part were our sewing machine lets me know i'm totally pushing her limits.

well, the thing is evolving at its own pace. i've found inspiration and support in the people that surround me and i want to thank them for that. big thanks! (you know who you are). i also want to give to the world and that's why i'm sharing this part of the process. i'd love to see what others do with the same patterns so i'm giving them away with a creative commons license which means that you can freely use them for yourself, copy, modify or distribute them, but if you are going to use them for commercial purposes you need my permission (read more here).

here are some links that i found quite inspiring:

• a short history of the modern messenger bag and a list of bag manufacturers from the respectable people at messengers.org
• p.a.c designs offers a very comprehensive list and resources for the materials they use, i like that, very open.
• this french bags are very appealing: cocotte equipment. and they have lots of pictures.
• those r.e. loads are soooo custom made and the web site has many pictures.
• review of a chrome messenger bag that i found helpful for some reason.
  
• some do-it-yourself bicycle proyects , i'd like to make some clipless combat boots.
• here is a list of inventive modifications and mounts for saddlebags that suits well my next proyect (check out this home-made saddle bag).
• make your own touring bags.
• cool homemade bicycle panniers.
  

This work is licensed under a Creative Commons License.

Updates:
-excerpt of an interview about making these bags.
-the following is the pattern i've been using for the latest bags. i've simplified the top and made it so the lateral seams end in the center of the bottom part. this also allows an easier way of attaching the straps directly into these seams. this new pattern still renders the same shape:

-Someone made a bag for under $5 using this pattern. includes actual construction. something i should have done some time ago.

- Bre from Make Magazine did a really cool podcast (video) making messenger bags out of plastic bags, he used the pattern above with a couple of modifications. Here is his illustration:

Check out the podcast here:
http://www.makezine.com/blog/archive/2007/06/make_a_messenger_bag_out_1.html
There is also a PDF with instructions here:
http://cachefly.oreilly.com/make/wp_messengerbag.pdf
Thanks Bre!

- i had a link for "recent work" but now it's not so recent (as of aug/2007), besides it was a photoset on flickr and my free account had more than 200 pics so i moved all the bag pics to a new photoset on zooomr, here is the link

- awesome pics of a build in this thread.

- now with flattr this! button: