This instructable is about a rather old project of mine. But as it seems, it didn't get too popular since then. I hope it changes after the submission of this instructable.
So what is it about?
The main idea describes how to clearly cut off the bottom from any glass bottles and then reuse it for something beautiful like a lantern, a flower pot, a vase or something totally different.
So for the first part you need:
a big bowl with cold water (may add ice, but without it works too)
40cm of a woolen thread for each bottle (any color, cotton works too, but no synthetics!)
a few empty clean and dry glass bottles (I prefer 0.7l wine bottles)
a few drops of petrol (the one that comes for your lighter works great)
a lighter or some matches
a glass cutter
Step 1: carve the bottle
Take the glass cutter and one of the bottles.
Well glass cutter is a bit of a strong word for this device, as it only carves in a small notch. With flat glass this is enough to perfom a smooth break along this notch, when the glass is bent. Unfortunately not so with round bottles, but one step after the other. First we need to carve the notch at the same height all around the bottle some few centimeters from the bottom of the bottle.
Go and find some timber or a book to adjust the height of the cutting edge roundabout 3cm above the table. Hold the glass cutter straight down and move the bottle on the table to get ONE clear notch. Don't try to go over and over again, this will only worsen the problem. First try with a few spare bottles before you take your best one. You need quite a bit of a strength to get this notch straight.
You could also clamp the cutter to some timber or build a v-shaped device to cut it.