So after much design (I will put up some scans of sketches later) I decided that for the final project, glass wine bottles would be the best choice. And after my friend (the same one as before) showed me this video: http://en.vidivodo.com/210769/beer-bottle-trick , I had my means (I had been trying to figure out how to do it before this with... little success). This is essentially working a controlled version of what happens when you pour ice water into a glass hot out of a dish washer. Through heating the glass along a specific line (just above the string) and then dunking it in ice water. It may take some practice, but after a few I generally do them first try every time now and have produced around twenty (me and a friend are trying to make 4-5 framed gardens in the next couple months). And so, here is a little tutorial on how I did this for my garden... but it could easily be modified I would imagine.
I tried to make this pretty self-explanatory, the second-to-last tier of frames is supposed to be depicting rotation of the bottle. I had a lot of success with Charles Shaw bottles (the green is [I'm hoping] beneficial in blocking the sunlight that algae uses to grow, and covers the roots). With those I found that three lengths of twine worked well. I also had many other types (brown is good, clear you'll have to paint), the thicker the glass, the more twine, I never used more than six lengths though (and I had some thick bottles). And try to keep the lengths relatively flat against the bottle. Make sure to tie tightly (or it either just shatters, or won't work), and trim the extra off after the knot (I didn't on the first tries and the bottle came out more like it had been in a bar brawl). I chose to submerge the bottle with the string in order to keep as much of the acetone in the string as possible when lighting, for higher temperature (because acetone is so volatile it will evaporate readily at room temperature). SAFETY TIP: DO THIS OUTSIDE! KEEP THE ACETONE CAN AND DUNK TUB AWAY FROM LIGHTING AREA. ALSO, THIS IS GLASS, BE CAREFUL WHEN HANDLING.
Once you have finished them, you will quickly notice the razor-like edges. I found that 80-100 grit followed by 600-1000 grit took the edge off. When doing this, you should probably wear a mask and safety glasses. Dunk the edges into water in order to prevent glass dust from getting into the air and to lubricate the sanding so things won't shatter on you. Then sand in a circular motion, perpendicular to the edge (across it), rotating the bottle to smooth all edges. And then rinse the sand off and you are good!
