Does anyone here have first-hand experience using polymer clay or sugru or other similar formable materials for creating little "plastic" parts such as simple light mounts, etc.? My main concern is with the mechanical durability of the resultant object once the material has been hardened, e.g can the object bend a little bit over and over again without snapping? Or can it be formed around a screw's threads and repeatedly get screwed without stripping? (sorry, can't think of a way to phrase that so it doesn't sound naughty)

I use a Reprap 3D printer to make my mounts.

I'll answer my own question in the remote event this comes up in someone else's forum search in the future.

After making my first post I discovered that they sell this stuff, "Kato Polyclay" at Hobby Lobby so I got some and made a couple of really simple shapes to test the durability. I tried making multiple similarly-shaped and sized pieces and curing them at different points within the specified curing range. No dice. Stuff is way too brittle for anything useful. Guess it's time to see if anyone I know has a 3d printer