Quote Originally Posted by firebird77clone View Post
So a light score (deeper isn't better) then temperature inversions. Cool, I need to try it
No, like cutting any glass, the deeper the score (the stress concentration) the easier the break, but going over a score a second time dulls your cutter and creates competing stresses. Press hard, once around. The bottle wall is 1/8" to 1/4", you'll not break it pressing against the cutter. Also, you don't ever want to score glass and set it aside for an extended time, coming back to break it later. The stress concentration will dissipate, leading to better chances of an off-line break.