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Re: [APD] Glass myths

I also found some hard numbers:


"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."

Jerry Baker
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Aquatic-Plants at actwin_com