4. Check to see if your glass has been properly tempered by looking at it with polarized glasses and shinning light through it. Tempered glass will have patterns of shadows (sometimes called "quench marks") visible with polarized lenses.
Shape or drill any holes in your glass before tempering. Once your glass is tempered it cannot be chop or drilled without shattering into bitty thumbnail-sized pieces.
2. Heat the glass you inclination to temperament to a temperature of at least 600 degrees Fahrenheit in an oven or a kiln.
3. Remove the glass from the oven or kiln (carefully, using tongs or a different paddle made for handling hot glass) and set it on a brick or cement surface and allow it to cool quickly by fanning it with cool (but not cold) air. It is the quick cooling of the outside surface of the glass that causes the molecular changes that make the glass tempered. Allow the glass to cool completely.
Tempering glass can be actually the interrogation. It requires heating glass to a appropriate eminent temperature and then allowing the glass to refreshing quickly. This alters the molecular Essay of the glass in such a conduct that the glass becomes up to six times harder than orderly glass, on the other hand at the alike bit it is enhanced brittle. One function to tempered glass (further the additional impulse) is that provided tempered glass should schism it crumbles into guarded chunks rather than sharp and potentially dynamite shards.
