Glass bottles melt between 850 and 1500 degrees Celsius


Unlike other substances, glass does not have a precise melting point. It stays in a mushy consistency in a temperature range of several hundred degrees Celsius. From about 1500 degrees can be spoken of a liquefaction. Sufficient viscosity for forming the previous glass bottle is given from about 600 degrees.

Oven indispensable and safety aspects

When glass bottles are to be melted, it is always necessary to have a stove capable of at least 540 degrees Celsius. Even when using a flame for the actual melting process, the glass must be "annealed" or "annealed" at about this temperature. In this way, secure material cracks and cracks can be avoided after the final cooling.

An essential and often overlooked safety aspect is the failure to recognize the glass transition temperature. Unlike many other materials, heated and hot glass does not show any optically identifiable warnings, such as annealing. If the glass bottle was cut transversely or longitudinally, the sharp edges should be defused by grinding or melting.

Temperature requirement and possible heat sources

The deformability of glass bottles starts at about 600 degrees. This temperature is reached by the following tools:

  • Bunsen burner
  • blowtorch
  • Camping gas cartridge

In order to liquefy the glass, which is already liquid, from a strictly scientific point of view, common gas welding equipment produces sufficient temperatures.

  • propane torch
  • butane burner
  • Oven with maximum temperature of 1500 degrees

Cooling break indispensable

After melting a glass bottle of any intensity, a "break" must be made on the way back to the cooled starting state. The glass bottle has developed tension through its deformation, which must be broken down during this break as possible.

Theoretically, this is a kind of virtual melting point or melting beginning, which is at about 530 degrees. After the peak temperature, the glass bottle or its successor must be kept at this temperature for at least one hour. This prevents the glass bottle from exploding in a new volume-filled form when the stresses suddenly "discharge".

Tips & Tricks

When melting glass bottles you should always expect "fading". Since different bottle types consist of different glass compositions, the melting properties vary. Before you heat up a particularly beautiful or rare specimen, practice with several similar prototypes and log your results.


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