You can also read this on my blog/website (new design!):
I just finished a fun spring project, as the weather warms up and we prepare to spend more time outside on our back porch. In addition to beer, I also make wine (from kits), so I took some blue wine bottles I had and cut them so that the tops of the bottles can be lanterns to put over candles on the table on our back porch. I'll use the bottoms of the bottles as votive candles, for our dining room.
It takes a little bit of patience, but its not hard. I have one of the least expensive bottle cutters available, called the G2 and I presume if you bought a better glass cutter, it would be easier. You use the bottle cutter to score the bottle and then alternate between dunking the bottle in hot and cold water, until the contraction and expansion causes the glass to break along the score line.
I had a 50% success rate - to get two candle lanterns, I had to use four bottles. What happened on the ones that failed is that the glass broke unevenly around the score - so there would be a jagged edge. Eventually, I learned to score the glass more heavily, deeply and leave the bottles in the hot water (on the stove) and the cold ice water (in the sink) for a longer period - not just dipping it in. I found that it worked best if I held it in the hot water for a minute, then the cold water for a minute, repeating, until the glass broke. Each bottle probably took four or five minutes.
After cutting the glass, I smoothed the edges with sandpaper, moving from coarse to fine.
