Quote: I don't like the glass due to the fact if it drops accidentally it will break and repair is going to be costly.
That's not necessarily true, it depends on the way it's done. I have a Dexlight flashlight with a glass lens and I can just throw it in a pocket or anything without being worried about it.
If it's tempered glass wrapped with a hard metal you should be able to stab it with an icepick
http://www.alumaxbath.com/tech/tgp.htm
Heat-treated glasses are classified as either fully tempered or heat strengthened. According to Federal Specification DD-G-1403B, fully tempered glass must have a surface compression of 10,000 psi or more or an edge compression of 9,700 psi or more. Heat-strength glass must have a surface compression between 3,500 and 10,000 psi, or an edge compression between 5,500 and 9,700 psi. The fracture characteristics of heat- strengthened glass vary widely from very much like annealed glass near the 3,500 psi level to similar to fully tempered glass at the 10,000 psi level.
HEAT TREATMENT PRINCIPLE
Glass can fracture when its surfaces or edges are placed into tension. Under these conditions inherent surface or edge fissures may propagate into visible cracks.
The basic principle employed in the heat treating process is to create an initial condition of surface and edge compression. This condition is achieved by first heating the glass, then cooling the surfaces rapidly. This leaves the center glass thickness relatively hot compared to the surfaces. As the center thickness then cools, it forces the surfaces and edges into compression. Wind pressure, missile impact, thermal stresses or other applied loads must first overcome this compression before there is any possibility of fracture.
This message has been edited since posting. Last time this message was edited on 23 June 2007 11:34
|