Does Sapphire Glass Hold up to Spatter and Grinding Sparks?

By Blaster (***)

Date 03-02-2014 07:34

Does sapphire glass hold up to weld spatter and grinding sparks?

Just curious is anyone knows the answer. Supposedly sapphire glass, such as may be found on a high end watch, melts at at around 3,000 C / 3,600 F.

Steel melts at around 2,500 F, but I assume it could probably get much hotter than that. (?)

I have been wearing a nice Citizen watch for the last year or so and the face still looks like new. My old and much cheaper watches always seemed to have spots burned into their plastic and glass faces pretty quickly.

Not sure if it is the sapphire material holding up better, or just dumb luck that nothing found this particular watch face in the last year.

Hard to believe anything you can see through would hold up to weld spatter.

However I am not about to give the watch an intentional spark and spatter shower to find out.

By Northweldor (***)

Date 03-03-2014 13:32 Edited 03-03-2014 13:52

I was recently doing a bit of research in this area, since Apple recently bought a building in Arizona and is rumored to be setting up a factory to manufacture sapphire crystal glass for the next Iphone. I was wondering what made artificial sapphire better than Corning's Gorilla glass, which is much cheaper.

It turns out that there is a correlation between hardness and melting point, and since sapphire is at a 9 on the Moh scale, and the only mineral higher is diamond (10), it's melting point is right up there too (2030 C.)! Since the boiling point of iron is around 2700 degrees Celsius, I think your crystal is probably pretty safe. The chart below illustrates this, and gives some explanation of why. (Sapphire isn't mentioned, but corundum (aluminum oxide) is the main ingredient in sapphire and is listed)

MeltingTemperatureandHardnessofMinerals.png (341k)

By Lawrence (*****)

Date 03-03-2014 16:02

Transparent Alumimum !

Just like Star Trek :)

By Metarinka (****)

Date 03-06-2014 20:35 Edited 03-06-2014 20:41

transparent aluminum ceramics do exist. Melt around 2015 deg C I believe they are harder than most glasses including sapphire glass. http://en.wikipedia.org/wiki/Aluminium_oxynitride it's also ~$15 /cm2 or $10K a square foot There's various other transparent ceramics mostly used for nose cones in missiles and transparent armor applications. http://en.wikipedia.org/wiki/Transparent_ceramics I've wanted to play around with some AION but it's really hard to get a sample even. I really want to cut a knife blank on my waterjet and make a decorative but functional transparent knife.

By ssbn727 (*****)

Date 03-07-2014 07:16

LOOSE LIPS SINK SHIPS!!! DO NOT GIVE OUR ENEMIES ANY IDEA'S!!!

By Metarinka (****)

Date 03-14-2014 19:03

well shoot, you can already buy plastic knives, glass reinforced plastic knives can be bought for a few bucks online.

By Blaster (***)

Date 03-03-2014 20:07

Thanks Northweldor

That is really incredible. My understanding is that the IPhone 5 already uses sapphire for the outward facing camera lens cover. Having the whole face of the phone in sapphire would be sweet. If it holds up like my watch, I think it would be very rare that it would ever pick up a scratch.

By JTMcC

Date 03-04-2014 00:00

Northwelder says:

I was recently doing a bit of research in this area, since Apple recently bought a building in Arizona and is rumored to be setting up a factory to manufacture sapphire crystal glass for the next Iphone.

I says:

It's not a rumor, construction is well under way and many UA welders are on site.
The unknown, to me, is the end user of the "special glass". The thinking was originally that it was Intel, who has several massive campus' a few miles away. Don't know about that part, maybe just hacking into the experienced clean room workforce that's in the area.
The Intel Fab42 was, a couple years ago, the largest privatly funded construction project on earth. With the largest crane on earth on site. Now it's mostly tool install/uninstall/move from here to there across several of the Fab's. Still thousands of construction workers there.
When I was there the construction workforce was just over 7000. That's a big old parking lot.
But rumors are (?) a twin sister plant to 42 is going in in the old 42 yard area just south of the building. The economy will dictate that.
The lightening speed of technical wafer size increases drives that industry pretty hard. Once a tool is in service it's almost obsolete for cutting edge work, still good for other uses.
But the Apple glass plant (I think they call it the Excelon(?) Project) is well under way.
That poor old solar venture, that swallowed several hundreds of millions of tax payer dollars didn't last but about 15 minutes. Some crooks got filthy rich off obama, huh? At least it's not empty.

Lot's and lot's of big bore chilled/heated water piping in those plants up to 42". Intel keeps manufacturing areas at about 70 degrees. When outside ambient is over 110. They bring clean rooms down to 1 ppm. That's just crazy, hundreds of thousands of tons of hepa to get to that point. All with mucho piping.

J