Internal Defects & Inclusions in The Glass
Nickel sulfide inclusions ("stones") can be present in the glass. The most common cause of these inclusions is the use of stainless-steel machinery in the glass making and handling process. Small shavings of stainless steel containing nickel change structure over time and grow, creating internal stresses in the glass. When these stresses exceed the strength of the glass, breakage results. This type of breakage is almost always found in tempered glass and is indicated by a distinctive "figure eight" pattern, with each "loop" of the figure eight approx. 30mm in diameter. The other use of the word "stone" includes that of the internal furnace wall known as refractory brick. As the molten glass pool is processed, the molten glass erodes the inner brick wall causing small pieces of the brick to become suspended in the molten glass solution. After the glass product is formed, these "stones" are embedded in the final product. The problem with this inclusion is that these stones, when the ware is heated, creates a thermal anomaly which creates a situation for glass explosion.
Read more about this topic: Spontaneous Glass Breakage
Famous quotes containing the words internal, defects and/or glass:
“No real “vital” character in fiction is altogether a conscious construction of the author. On the contrary, it may be a sort of parasitic growth upon the author’s personality, developing by internal necessity as much as by external addition.”
—T.S. (Thomas Stearns)
“The East is the hearthside of America. Like any home, therefore, it has the defects of its virtues. Because it is a long-lived-in house, it bursts its seams, is inconvenient, needs constant refurbishing. And some of the family resources have been spent. To attain the privacy that grown-up people find so desirable, Easterners live a harder life than people elsewhere. Today it is we and not the frontiersman who must be rugged to survive.”
—Phyllis McGinley (1905–1978)
“Like a wild stranger out of wizard-land
He dwelt a little with us, and withdrew;
Black and unblossomed were the ways he knew,
Dark was the glass through which his fire eye shined.”
—Edwin Arlington Robinson (1869–1935)