Homemade Pannier Plastic Stiffener?

[jeremy11]

What plastic material and thickness would be good for a rear pannier for bike commuting with engineering textbooks?
US Plastics has a substantial selection of plastic sheet, such that its hard to tell what would be best without seeing it in person.
I'd like to try a rear pannier that pops off quickly into a shoulder bag.

[boddunn]

I used Coroplast on some panniers I made, it's hard to explain what it is but you've probably seen it before with out realising, it's very stiff for the weight.
 In the UK the for sale signs for houses are made of it and in the US I know from other people campaign boards are made of them. There's lots of thickness's, my Carradice pannier uses quick a heavy grade but they weigh about a kilo each!

[jhl99]

Coroplast is easy to define  .   It is a corrugated material like corrugated cardboard, except instead of paper for the material, the material is plastic.  Like the cardboard, it folds easier along one direction (bend line parallel to corrugations).

For a pannier stiffener, I would go with 1/8" material... maybe polypropylene.  I think ABS is too brittle.

McMaster Carr is a pretty good resource:
http://www.mcmaster.com/#8742k233/=a6riqm

[Done]

I've been thinking of using carbon fiber sheets.

http://dragonplate.com/ecart/

[trebor]

i was researching for sources of plastic sheets recently and didn't find what i was looking for. thanks for asking Jermey11 and thanks for the answers everyone!

[wookieone]

I've used 1/16th inch lexan, maybe it's 1/8th", but get it from a auto glass shop. No idea how light it is in comparison, but it is tough as can be, not too hard to cut, and just flexible enough to get into tight spots. Plus it is clear. Jefe

[jhl99]

I do not think out of box!  Carbon Fiber?  I would never have considered it... it is light, and so will make your wallet equally light:
 
"EconomyPlate Solid Carbon Fiber Sheet ~ 1/16" x 12" x 18"  $90

I would be concerned with the thin edge and rough fiber edges abrading the pannier fabric though. Would you need to epoxy seal the cut edges to smooth them out?

When I couldn't find any plastic (years ago) I used some thin  (5/32" ?)  plywood for the stiffeners.

 

[Done]

... it is light, and so will make your wallet equally light:

Yep, that's why I am still in the "thinking" phase! I've been looking for a cheaper local source so that I can find some too look at.

[bmike-vt]

Flexible cutting board material from the grocer also works. Cheap too.

[jhl99]

I just finished a set of 'mini' panniers for use this summer and as I was doing finally assembly, it occured to me it doesn't really matter what you make the stiffener out of... it can be easily changed if you come accross a better alternative.  Make your panniers so that only the screws for the hooks and bottom retention strap hold the stiffener in.  If the stiffener breaks or is not appropriate, remove it, trace its profile onto new material, cut out the new stiffener and install.

***
These mini panniers, 10" hgt x 6" wide x 4 "dp = 240 in^3 per side (approx 10 liters) + a expanding top cover that can compress a jacket or whatever over the top of the main compartment.  Too small for text books.... stiffener is some polypro? (1/8" thk) that was lying around.



Installed on bike:

[jeremy11]

FINISHED.
I picked up some 1/8" plexiglass from the hardwear store for $4, if it breaks or is too floppy I'll just get the 1/4" version.
Full VX42 fabric.


Fitted slots for the pocket protector and TI-83 


Sewed it up last night, except for the shoulder strap which I made this morning, then rode for a few hours to test it.  Pavement in a tough headwind to the trails, then on easy trails for a little while.
It clips on in 1 min, and comes off in 30 sec, and carries comfortably with a removable shoulder strap.  Attachment is with 2 fastex buckles over the top rail and a velcro/fastex buckle around the lower part of the rack.  It rides fine on easy trails.
This was a test ride with soft fluffy stuff in it, but preliminary rides with textbooks inside are quite positive.

[donmeredith74]

Instead of buying Coroplast from MMC you can experiment with it by recycling the real estate signs in the neighborhood... I've done a few project mock-ups with that material. Can't beat the price.

DM