Q&A for How to Melt Glass Bottles

Theoretically, you could use an outdoor fire pit to melt glass. The problem with this technique is reaching the temperatures you'll need for an effective melting and controlling the temperature so your bottle art doesn't come out misshapen. Generally, a kiln is the recommended route for bottle melting.

You could - but without a kiln, you won't be able to anneal it properly. The glass will have stress in it and is likely to break in the dishwasher or randomly.

No. A microwave is not a kiln.

A blow lamp (Am. English: blowtorch) can be used to shape the glass, especially when using other glass working tools. However, applying the correct heat throughout the bottle to melt it entirely will be difficult with a blow lamp, which is intended to apply heat to a specific point.

You don't need to break it first. Heat it to about 200 degrees C and drop it into a bucket of cold water. It will disintegrate into small pieces.