Re: What is the best screen protector?
I worked in a large glass manufacturing plant for a decade. We had 3 different glass tempering furnaces. When I first started there, my company had the largest tempering furnace West of the Mississippi. That furnace could barely temper 1/8", and the results were not optically ideal. A panel would have many waves and distortions.
I have a very hard time believing that the "tempered glass" protectors are really tempered. I completely understand the method of glass tempering, both in theory and practice.
The thicker a glass panel is, the easier it is to temper. Thin glass gets quite difficult, when you get under 1/8". The thinnest we could ever temper was 3/32". I did see one piece of 1/16" get tempered by accident. It was wavy like a potato chip, and we were all amazed that it made it through the furnace without exploding.
Cliff notes on glass tempering: bake the glass until it's at the desired temperature, then blow compressed air on the panel to cool the outside faster than the inside. You have to get the exterior of the panel 500 degrees cooler than the interior, in order to produce a decent temper. 1/2" thick glass takes very little air to achieve this, and those panels would come out of the oven at about 200 degrees and take hours to reach room temp.
1/8" needed so much air blown on it, that the entire plant had to wear ear protection because of the extreme noise from such high air pressure being released while we tempered it, and it came out of the oven at room temperature. It reaches 2000 degrees before air is blown on it for tempering. The air pressure often shattered the thin panels inside the oven.
We had to install a 5,000 gallon air tank just so we could temper 1/8".
The furnace has hundreds of air nozzles spaced out in a grid over the panels.
In short, I call B.S. on tempering glass under 1/32".
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