Glad you all found my accidental experiment useful.
David – the drainage pipe and caps were not shockingly expensive, especially the caps.
As opposed to the ABS version I built first, which priced out around $40 IIRC:

The screw thread caps really drove up the price, but I couldn’t find simple slide-on end caps.
Other disadvantages of this ABS cache:
– The screw-on caps required toxic ABS cement to install. Took a couple of weeks of airing out before I stopped smelling that. Didn’t want that chemical seeping into the water!
– ABS weight as shown: 922 grams (2 pounds). Drainage pipe version: 491 grams (1.1 pounds)
I kept the ABS version as a possible “torpedo toilet” for rafting:
http://www.blm.gov/or/resources/recreation/rogue/portable-toilets-kayak.php
The drainage pipe cache could be made more raccoon proof if you felt the need, by adding one or two wood screws through the side of each cap into the pipe. Remember to bring some kind of screwdriver!
— Rex

