I've seen quite a few pages regarding DIY panniers around the internet, but wanted to share my own mis-adventures and successes over the years I've been using/modifying mine.
A few years ago when I started bike commuting, I got tired of wearing a heavy backpack, so decided to make some panniers.
I used this as a jumping off point: http://www.instructables.com/id/How-to-make-DIY-Bike-Panniers/
I started with:
- 2 13"x13"x4" surplus musette bags
- 2 bungee cords
- 2 linoleum tiles (used as rigid frame/back for bags)
- various 1/4" nuts and bolts
- asst. picture hanging hardware kit
I covered the sticky back of the linoleum tiles in duct tape so it didn't stick to anything, and maybe was reinforced somewhat.
Things were initially mounted more or less as per the instructable using hanging hooks, and bungees.
Problems I had (and solutions):
- The tiles were a terrible idea, and disintegrated quickly. I replaced them with vinyl plexiglass sheets which have been quite sturdy and even survived a few tumbles.
- The hooks weren't enough to keep the bags on bumpier terrain such as my commute down Friendship Ave. (my laptop flying off my bike in traffic got irritating after awhile) At first I mounted some rubber lined pipe camps, and tied them on with para-cord. Recently I splurged on some real locking pannier hooks for one bag, and they've worked great:
http://www.bikebagshop.com/lone-peak-pannier-hook-set-p-1675.html
- Canvas is only sort of water resistant. I usually just line them with trashbags if necessary, but I've been meaning to coat them with scotchguard or somesuch.
- The exteriors looked a little bland after awhile, so I decided to spray paint on a celtic sort of border.
Overall cost for both was $50 including the musette bags, so pretty respectable for the volume and nifty DIY aesthetic.
I have some random pictures from various incarnations of the panniers here:
http://www.flickr.com/photos/besugo/sets/72157627463794180/
I think this post is a little longer than I wanted, but if you're interested in more of a play-by-play for constructing your own, let me know.