Cubify 3D Printers Aren't Just for Squares (Video)
There are other 3D printers out there, but Cubify claims theirs is easier to use, has easier cartridge changes, and is all-around nicer and cooler than their competition. And Timothy Lord found them at Google I/O 2012, which means Google thinks they're cool, too. Wow. At only $1300 for their basic model (plus $50 each for the plastic "print" cartridges), every home should have one of these. Or maybe two or three. Or maybe Hackerspaces will buy all of them, and that's where we'll go to satisfy our lust for 3D printing.
Unfortunately all plastics are different.
No plastic is the same, plastics have different composition, additives, melting points, all sorts of different properties that really makes it impossible to melt them together and expect any sort of consistency.
OTOH it instead of melting the plastics, your old bottles could be shredded somehow into powder and then mixed with something sticky, some glue or epoxy, but even then different behaviours of different plastics would be problematic.
You can't handle the truth.
Not sure why you're modded off-topic - considering that Shapeways or, and I guess I'll plug their 'competitor' here, i.materialise, are a great option for those who want high quality (much higher than what you get out of Makerbot etc.) for a low price (compared to buying a 3D printer (kit+assembly)) with practically zero hassle.
I guess this Cube thing is somewhere between the Makerbots and the z-corp et al high end devices, but still more on the Makerbot end.
There are also desktop 3D printers that cost a bit more but may be worth the bother if you need what they do. One site that comes to mind is http://desktopfactory.com/
It occurs to me, reading the page there, that 3D Systems may be on their way to trying to corner the consumer/prosumer market.