You will need a kiln. Fire to cone 011.
I have a friend that does this and sells them at a shop in a small town here in missouri. She puts the bottles on their side in a kiln and gets the hot enough to become soft. Then she uses several tools to shape it out flat. The trick is to be fast as glass cools very quickly and also, you must be gentle. Glass will break if you try to make sudden moves with it.
Of course, the other thing is knowing how hot to get it and I do not know the temp. She uses but I do know it will burn off any labels of left on and that causes black etching in the glass (looks bad). There are some wine bottles that have been painted and these tend to turn out the best.
Of course, the other thing is knowing how hot to get it and I do not know the temp. She uses but I do know it will burn off any labels of left on and that causes black etching in the glass (looks bad). There are some wine bottles that have been painted and these tend to turn out the best.