Melted Wine Bottles When Making Glassware Out Of Recycled Glass Wine Bottles, How Can I Melt The Edges Without Cracking It?

When making glassware out of recycled glass wine bottles, how can I melt the edges without cracking it? - melted wine bottles

I do not want to soften the edges by melting the glass, just cut loops. I have tried to take the torch, but the broken glass. Do I need a stove for her, and if so, how long at what temperature?