Content continued at Formufit Corners
- Less than $2 for 1" size on Amazon - 
- Menards has these furniture grade corners - 
- Formufit - PVC corner construction set - PVC 101
- How-To Manuals - PVC Field Manuals freely sourced by FORMUFIT for cutting, cleaning, assembling, bending, sizing.
- Plans and Design Ideas - http://www.formufit.com/free-pvc-projects-plans/
CAD File Sources
- McMaster-Carr - Schedule 40 DWV Drain waste Vent + Many Others - 
- Note that, ex., standard pipe has 1/4" wall for 3", vs 1/8" wall for thinner
Source Catalogs with Drawings
- Charlotte Pipe - 
PVC Pipe Dimensions Only
- Schedule 40 and 80 - 
- Typical US toilets connect to a 4" pipe. A 'closet bend' connects from the 4" pipe of a toilet to the rest of the plumbing, which is 3". .
...of note, this company will offer store credit for creations submitted to their free online library. In addition, they have Sketchup creations that could be of use to your Factor e Farm. Perhaps an informal partnership with OSE could help you source much needed materials?
- 6" PVC - 10' - $40 -