How to cut a glass bottle or jar with a smooth clean cut
This video in Russian (with english subtitles) by Roman Ursu shows how to cut a glass bottle into 2 with water and oil. First he fills the glass bottle or jar with water, and then places it in a bowl with water to the same level as the water in the bottle. Next he carefully adds a thin layer of oil on top of the water. Finally to make the cut he heats up the blade of a utility knife and places it in the layer of oil which creates a temperature difference in the glass where the oil is touching it, and the glass which is touching the water below, causing it to break with a smooth cut.
