Thanks for all the great ideas. I've just ordered my "panniers". I'll post again as I make progress fitting them. I've done a fair bit of research and might as well share my other ideas in case it's of use to anyone else thinking of making panniers from other stuff. Warning - long essay follows!
I looked at moderate size boxes, roughly 40 cm wide, 35 cm high and 20-25 cm deep, and as light as possible without compromising strength too much. I decided I wouldn't discount side-opening ones, but I'd prefer top-openers.
And this is what I've settled on using:
- Keep your luggage in alphabetial order?
- box file.jpg (11.52 KiB) Viewed 7987 times
http://www.amazon.co.uk/gp/product/B004 ... iceproductThey're about £20 in the shops and online, but I noticed amazon are selling them at £12 each, although temporarily out of stock. I'm not in any great hurry, so that'll do me - £24 a pair is a bargain for some metal top-opening panniers! They're not exactly Ard Cases, and there will be some fettling to do. The plastic strap handle is popped through two holes in the lid, so I'll put a piece of aluminium plate or something over the top (after removing the handle), which would also stiffen the only part that's a bit wobbly (I've looked at them in W H Smiths), and then I'll probably add some bungee attachment points. The main section seems fairly rigid, and would be waterproof with a bit of glue or sealant down the corners - they're basically just bent steel. The lid and base meet with a flat edge several mm wide, which could take a thin layer of something to seal it. I'll probably strengthen the back internally.
The clasp and lock are so cheap and nasty that locking it would probably only ensure it stays closed in transit! They will need some aftermarket locks, under a tenner for two. I'll use either a 1/4 turn cam lock, which could latch onto a bar inside the lid, but there's a small chance of something inside fouling it and stopping it unlock, or an external hasp with an integral lock (I don't really want padlocks rattling). The latter have the advantage also that they fold over their own fixing screws when closed, whereas the bracket for the cam would leave bolt heads on the outside that would need covering somehow.
Other tweaks will include a rounded flight-case corner thingy or two (I may have some in the shed or I can knock something up) - to make the panniers a bit safer in use and avoid the sharp corners ripping my bike cover - and some padding inside (cut up cardboard box and blue-tack will do the trick and be replaceable every now and then).
They should work out at about 22 litres each, which is a bit smaller than I first wanted, but not a bad compromise considering the cost, weight (2.5kg-ish each) and the lower aero drag. They should just fit ok without remounting the indicators. You can get silver and other colours.
Now, other contenders -
If you're going for strength and waterproofing, these heavyweight tool boxes/flight cases from Duratool look great:
http://cpc.farnell.com/1/1/47578-waterp ... atool.html (and there's a smaller one, the 467).
They require a padlock to secure them, but you probably can't get much tougher plastic than these. Pressure valve. Waterproof seal and padding included. The downside for me is they're heavy (although the data is wrong and says 9 kg for the big one, when it's actually 5.6kg - I asked them to weight them - and the smaller one is 3.4kg). I don't want to lug 7 kg of empty box around, personally. They're a little over £50 for the pair, since at the moment on that site orders over £45 are postage free! (And they'd cost you nearer £90 a pair on some sites I've seen.) The data is all a bit off - virtually nowhere is there a correct picture of the 468 - they all show the 467 - so I googled and found this (note, even on the product itself there's a picture of the wrong box!). It has clasps down each end as well as two on top:
- duratool 468sm.jpg (68.71 KiB) Viewed 7987 times
An LP flight case is about the right dimensions (an LP is about 32 x 32 cm). The ones holding a nominal 50 look a good width. There are quite a few different types.
This is a sleek-looking thing
http://www.amazon.co.uk/RECORD-BOX-ALUM ... p_t_3_TBQ0...the weak point probably being the locks, but they might just deter the casual thief. £65 a pair - craaaaaazeee money! It looks like the closure has enough width to put some better waterproofing in, although the sections of aluminium and plastic might leak between them. One potentially useful thing with this is that once open, the top lifts right off.
Here's another, tougher-looking and heavier at about £90 a pair
http://www.amazon.co.uk/Euro-Style-Reco ... p_t_2_TBQ0Instead of having a pointless lock, this has a more solid-looking clasp that you could padlock, which might be a lot more secure if you can stop it rattling. Again, there are places water might seep in.
Something in between
http://www.peripheralcentre.co.uk/cd-dv ... for-50-lpsThis is the cheapest LP case I've seen (other than PVC covered cardboard ones!) - two, with shipping, comes to £53.50. Again, two relatively useless locks, and they're probably in the region of 3.5 kg each.
For something really cheap, you might consider these plastic suspension file boxes
http://www.ebay.co.uk/itm/Pierre-Henry- ... 416824965d...and why would you buy one at £8.99 plus £2.95 economy delivery when you can pick one off the shelf at WHS for £8.62? Yes, that's £17.24 for a pannier set! There are quite some drawbacks tho - the sides flex quite badly when the lid is open (although when it's closed they are pretty stiff) so they'd probably need something to stiffen them and transfer load to the rack - aluminium bar or something round the inside. It has the handle through the top like the metals ones I'm getting, so that would need plugging, but worse, the lip is very narrow and almost impossible to waterproof. Probably the best way to waterproof these is forget all the gaps in the lid and stretch an elasticated rain cover over the top - the rest is snug as a bug. The depth starts at about 24 cm at the lid, but the front and back slope and the lower 3/4 of the box is only about 20 cm. The sides slope too and have integral handles in the walls, so they're on the small side. The clasp closes (very positively, actually) onto a small tab of the base with a hole, which could take a small padlock. The plastic is pretty thin, so it wouldn't take a lot to cut through it. But if you were after some dirt cheap ultralite panniers and don't have much worth nicking, these might be just the dogs.
Beyond that in the cheap stakes, there are "really useful boxes" of various sizes - like tupperware - for going to parties?
One interesting idea I had was a collapsible box, but I didn't find any suitable - the idea being that if you fix the bottom to your rack, then when they're not in use they can be folded into the side of the bike to reduce drag. I thought long and hard about these, which could be fixed so that the little trap door on the end was the opening, and the "top" would be glued on permanently -
- 35-Litre-Really-Useful-Folding-Front-Opening-Storage-Stackable-Box-Office-Home.jpg (35.65 KiB) Viewed 7987 times
...but it would take so much to strengthen them, waterproof them, add locks and paint them, it's not worth the hassle.
I'm even considering some cheap plastic boxes, like fishing tackle / seat boxes, locked with padlocks. I'm a cheapskate, that's why I got the bike I got. 