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(Topic ID: 177463)

Tempered glass a must..


By Milltown

3 years ago



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  • 144 posts
  • 57 Pinsiders participating
  • Latest reply 3 years ago by polyacanthus
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There are 144 posts in this topic. You are on page 3 of 3.
#102 3 years ago
Quoted from Homepin:

One way of telling it is tempered (if you are lucky) is look for the small cork spacers that are often used by the company that does the actual tempering.

It's even easier if you have some polarized sunglasses on hand, and a laptop screen/cell phone screen:

#103 3 years ago
Quoted from msjussaume:

....So I was talking to Milltown when this happened...No excessive force or disrespect to the machine at all, just leaning on lock bar really and bullshitting ..then crack. Totally surprised, actually took a couple of seconds to realize what happened.
Very happy no one got hurt, also very happy that I found out it had regular glass as it located at end of a row of pins and the whole length of the glass is exposed and easily accessible by people walking by. It never occurred to me that someone would be as foolish as to replace with standard glass.
I have several grand kids that play and fear things could have been a lot worse. I'm going to check all my machines that don't have a stamp or etching to make sure they're all tempered.
I think I should say.. Thanks Milltown!

Haha.. I still feel bad.. but I'm glad because like you say no one was hurt ...expecially grand kids ect... as soon as your other piece arrives we will install and be happy.. haha

#104 3 years ago
Quoted from Insane:

not all tempered will have a logo, you can order it without one. So just because it doesn't have one, that doesn't mean it isn't. Just have to look for more evidence .

My glass guy says if no stamp you can scratch it easily to tell.. or if you have a definite tempered piece side by side is easy to tell in appearance...

-1
#105 3 years ago
Quoted from TigerLaw:

The glass will sometimes just inexplicably shatter. This happened to Pinside moderator Marcus not too long ago (maybe three months ago). I've heard of it happening to others as well. Just a temparture change can sometimes trigger it.

The problem with ANY glass is that over time it is stressed and gets micro-fractures. The internal stresses build up and eventually a sudden temperature swing, vibration, or pressure will be the final crack needed. Then POP. Same for both sheet and tempered.

That is the physics of glass. Granted if you have a high quality glass compostition that is very homogeneous, then it is very unlikely to happen under and normal condition (even over a long perios of time).

It has to do with COE (Coeffiecient of Expansion) and that glass is really a heterogensous composition. All these different parts will expand and contract at different rates. These small difference all add up over time. Keep in mind that glass is really a liquid in a solid state (go look at old leaded windows and you will see they actually slump over centuries and are thicker at the bottom)

#106 3 years ago
Quoted from Whysnow:

Keep in mind that glass is really a liquid in a solid state (go look at old leaded windows and you will see they actually slump over centuries and are thicker at the bottom)

Actually, that's a myth.

Glass is as solid as any other solid.

The deformities in antique glass simply have to do with the old imperfect methods used to form the glass in the first place.

http://io9.gizmodo.com/the-glass-is-a-liquid-myth-has-finally-been-destroyed-496190894

#107 3 years ago

Safety or not, tempered glass also has its downsides...

Ooooow my head!Hey look Ted... Glass!

This happened earlier this year. We temporarily had a speaker box on top of the game (yeah, I know). But for some reason, some pinball designer decided to put a shaker motor in this game (duh). The speaker fell down and went through the glass just as I was in the middle of a great multiball.

Had to take apart the game completely. Glass literally EVERYWHERE!

#108 3 years ago
Quoted from robin:

Safety or not, tempered glass also has its downsides...

This happened earlier this year. We temporarily had a speaker box on top of the game (yeah, I know). But for some reason, some pinball designer decided to put a shaker motor in this game (duh). The speaker fell down and went through the glass just as I was in the middle of a great multiball.
Had to take apart the game completely. Glass literally EVERYWHERE!

Yup... deff a downfall .. yikes .. lol

#109 3 years ago
Quoted from ForceFlow:

Actually, that's a myth.
Glass is as solid as any other solid.
The deformities in antique glass simply have to do with the old imperfect methods used to form the glass in the first place.
http://io9.gizmodo.com/the-glass-is-a-liquid-myth-has-finally-been-destroyed-496190894

that is actually wrong. Old leaded glass in particular has been shown to slump over time under normal conditions and time.

#110 3 years ago
Quoted from Homepin:

The mark that identifies a piece of glass that is built into the glass by the factory doing the tempering is called a "bug".
Homepin has chosen not to put a bug in our glass but rather we are screen printing the corner with the full details of the glass as required by law in many countries (including the USA).
One way of telling it is tempered (if you are lucky) is look for the small cork spacers that are often used by the company that does the actual tempering. This will probably be a different place from the one that actually cuts the glass to size. They use the cork squares at the place we use to stack many sheets at a time so they can go into the oven.
I'm sure there are many other ways to temper glass but this is the way the place we use does it.

You can specify 'no logo' or 'no bug' when ordering tempered glass. Also, the cork squares are used all over in the industry not just at tempering shops for tempered glass. They come in a big roll and you can stick them to whatever the hell you want

#111 3 years ago
Quoted from TigerLaw:

The glass will sometimes just inexplicably shatter. Just a temparture change can sometimes trigger it.

Years ago my wife and another couple used to go to IHOP every Sunday morning. The line was always out the door and we were standing with a bunch of other people and the rear glass on a blazer style truck just shattered. No one around it, nothing done. The owner came out and was like who broke my glass.

#112 3 years ago
Quoted from ForceFlow:

Actually, that's a myth.
Glass is as solid as any other solid.
The deformities in antique glass simply have to do with the old imperfect methods used to form the glass in the first place.
http://io9.gizmodo.com/the-glass-is-a-liquid-myth-has-finally-been-destroyed-496190894

Quoted from Whysnow:

that is actually wrong. Old leaded glass in particular has been shown to slump over time under normal conditions and time.

download (resized).jpg

#113 3 years ago

If you believe Scientific American, glass is an "amorphous solid." https://www.scientificamerican.com/article/fact-fiction-glass-liquid/

#114 3 years ago
Quoted from SirScott:

If you believe Scientific American, glass is an "amorphous solid." https://www.scientificamerican.com/article/fact-fiction-glass-liquid/

Quoted from Whysnow:

that is actually wrong. Old leaded glass in particular has been shown to slump over time under normal conditions and time.

From the article:

----
Whatever flow glass manages, however, does not explain why some antique windows are thicker at the bottom. Other, even older glasses do not share the same melted look. In fact, ancient Egyptian vessels have none of this sagging, says Robert Brill, an antique glass researcher at the Corning Museum of Glass in Corning, N.Y. Furthermore, cathedral glass should not flow because it is hundreds of degrees below its glass-transition temperature, Ediger adds. A mathematical model shows it would take longer than the universe has existed for room temperature cathedral glass to rearrange itself to appear melted.

Why old European glass is thicker at one end probably depends on how the glass was made. At that time, glassblowers created glass cylinders that were then flattened to make panes of glass. The resulting pieces may never have been uniformly flat and workers installing the windows preferred, for one reason or another, to put the thicker sides of the pane at the bottom. This gives them a melted look, but does not mean glass is a true liquid.
----

#115 3 years ago
Quoted from ForceFlow:

From the article:
----
Whatever flow glass manages, however, does not explain why some antique windows are thicker at the bottom. Other, even older glasses do not share the same melted look. In fact, ancient Egyptian vessels have none of this sagging, says Robert Brill, an antique glass researcher at the Corning Museum of Glass in Corning, N.Y. Furthermore, cathedral glass should not flow because it is hundreds of degrees below its glass-transition temperature, Ediger adds. A mathematical model shows it would take longer than the universe has existed for room temperature cathedral glass to rearrange itself to appear melted.
Why old European glass is thicker at one end probably depends on how the glass was made. At that time, glassblowers created glass cylinders that were then flattened to make panes of glass. The resulting pieces may never have been uniformly flat and workers installing the windows preferred, for one reason or another, to put the thicker sides of the pane at the bottom. This gives them a melted look, but does not mean glass is a true liquid.
----

interesting.

In real world examples from friends in the glass community, they have replicated making low melt glass which slumps over time (even when maintained below the melting point)

#116 3 years ago

All very interesring.. I've replaced windsheilds in 50s cars that moisture also gets in between the layers of non safety.. very odd.

#117 3 years ago
Quoted from Homepin:

The mark that identifies a piece of glass that is built into the glass by the factory doing the tempering is called a "bug".
Homepin has chosen not to put a bug in our glass but rather we are screen printing the corner with the full details of the glass as required by law in many countries (including the USA).
One way of telling it is tempered (if you are lucky) is look for the small cork spacers that are often used by the company that does the actual tempering. This will probably be a different place from the one that actually cuts the glass to size. They use the cork squares at the place we use to stack many sheets at a time so they can go into the oven.
I'm sure there are many other ways to temper glass but this is the way the place we use does it.

Illegal or not, I'm glad we can source tempered glass without the ugly mark on it if you specify to the person making the sheet for you.

#118 3 years ago

I had a piece of non tempered glass that I pulled from a machine split in half on me... One shard in one hand, one in the other.. Almost dropped them on myself. I got lucky!

#119 3 years ago
Quoted from Otaku:

Illegal or not, I'm glad we can source tempered glass without the ugly mark on it if you specify to the person making the sheet for you.

Of course you can, I was speaking as a manufacturer and I must be a lot more responsible than doing something like that. Homepin machines comply with all legal requirements in the countries we export to.

I'll bet the original glass supplied from the factory fitted to your new Stern pinball has the required markings.

#120 3 years ago
Quoted from robin:

I was in the middle of a great multiball.

"You missed everything!"

#121 3 years ago
Quoted from Homepin:

Of course you can, I was speaking as a manufacturer and I must be a lot more responsible than doing something like that. Homepin machines comply with all legal requirements in the countries we export to.
I'll bet the original glass supplied from the factory fitted to your new Stern pinball has the required markings.

It's probably under that sticker..... actually, I don't think it is. No markings on the glass of my NIB Stern machine.

#122 3 years ago

Does the coating on PDI hold it together in the event of a break? I haven't had any PDI but sure a friend said it has a layer applied to it so curious if anyone has seen any PDI break and if it's held by the coating? Would be another great reason to have PDI, when remembered breaks it does have a habit of going everywhere and getting in the tiniest of places

#123 3 years ago

removed as it was helpful, can't have that. Non-verified accounts are nothing but liars and trolls

#124 3 years ago
Quoted from volcanodiver:

No, its not a film

Thanks for the reply and clarification, I wasn't totally sure haven't seen a sheet of PDI in years since I had to sell my collection.

#125 3 years ago
Quoted from Whysnow:

that is actually wrong. Old leaded glass in particular has been shown to slump over time under normal conditions and time.

Interesting debate.

When I went to school a lab class teacher whilst discussing glass temp point between its solid and liquid states made a real world observation that large (high street shop windows) plate glass was made with a thicker end as overtime it would flow with gravity. Now I did not learn very much at this school as time has shown me so it would not surprise me that this was wrong as well. Worse still I have told countless people that over the last 40 years so I could have being spreading more manure than I thought.

-1
#126 3 years ago

That is true, check out the windows in a very old house...it slumps down...

#127 3 years ago
Quoted from TheMickster:

That is true, check out the windows in a very old house...it slumps down...

That's because how the glass was originally formed. It doesn't change, flow, or collect in a puddle over time.

http://engineering.mit.edu/ask/how-does-glass-change-over-time

http://www.livescience.com/32119-do-old-glass-windows-sag.html

https://en.wikipedia.org/wiki/Glass#Behavior_of_antique_glass

http://science.howstuffworks.com/science-vs-myth/everyday-myths/10-false-facts4.htm

https://en.wikipedia.org/wiki/Float_glass

https://www.scientificamerican.com/article/fact-fiction-glass-liquid/

If glass really did flow, you would see glass windows with a gap at the top that sags in the middle, or puddles of glass and an empty window frame. None of that actually happens.

#128 3 years ago
Quoted from J85M:

Thanks for the reply and clarification, I wasn't totally sure haven't seen a sheet of PDI in years since I had to sell my collection.

the vids on post 73 and 74 are PDI glass.

#130 3 years ago

Annealed or plate glass is extremely flat, one of the flattest surfaces you can get for the money. When this annealed glass goes through the tempering or toughening process, it is heated red-hot and then quenched quickly. As the red-hot glass passes through the tempering furnace it can sag between the conveyor rolls causing what is known as "roller wave", and during the rapid cooling process this roller wave becomes solid. This can be seen on most if not all tempered glass if you look at a reflected image at a very sharp angle and slightly move your viewing angle you will see the image slightly distort or not track smoothly. If you see this distortion then you have tempered glass. If the image does not distort then it is likely annealed. I'm in the glass biz, and this is how i can tell if an unlabeled piece of glass is tempered or not. NEVER assume that if the edges are sanded that it is tempered.

#131 3 years ago

I can barely see out of some of the windows of my house. I say it flows. Looking out of some of my 115 year old windows, is like looking in a funhouse mirror.

#132 3 years ago

I can't imagine glass slumping ? My glass guy says no as well.. you will never ever heat any glass to the temp it was made not in a car nor machine nor home...
Crazy part is it starts from sand.. wtf.. lol very odd ... I'm with no slumping glass .... made with slump in old work conditions ect makes much more sense ....

#133 3 years ago
Quoted from ForceFlow:

That's because how the glass was originally formed. It doesn't change, flow, or collect in a puddle over time.
http://engineering.mit.edu/ask/how-does-glass-change-over-time
http://www.livescience.com/32119-do-old-glass-windows-sag.html
https://en.wikipedia.org/wiki/Glass#Behavior_of_antique_glass
http://science.howstuffworks.com/science-vs-myth/everyday-myths/10-false-facts4.htm
https://en.wikipedia.org/wiki/Float_glass
https://www.scientificamerican.com/article/fact-fiction-glass-liquid/
ยป YouTube video
If glass really did flow, you would see glass windows with a gap at the top that sags in the middle, or puddles of glass and an empty window frame. None of that actually happens.

I agree .. impossible.. made that way 120 years ago I can agree to .. but no way they ever reach the temp it takes to make it...I'm with ya..

#134 3 years ago
Quoted from bbriese:

Annealed or plate glass is extremely flat, one of the flattest surfaces you can get for the money. When this annealed glass goes through the tempering or toughening process, it is heated red-hot and then quenched quickly. As the red-hot glass passes through the tempering furnace it can sag between the conveyor rolls causing what is known as "roller wave", and during the rapid cooling process this roller wave becomes solid. This can be seen on most if not all tempered glass if you look at a reflected image at a very sharp angle and slightly move your viewing angle you will see the image slightly distort or not track smoothly. If you see this distortion then you have tempered glass. If the image does not distort then it is likely annealed. I'm in the glass biz, and this is how i can tell if an unlabeled piece of glass is tempered or not. NEVER assume that if the edges are sanded that it is tempered.

This makes sense ...I agree 1.000 percent..

#135 3 years ago

Starting to look like the Flu shot thread in here.

#136 3 years ago
Quoted from bbriese:

Annealed or plate glass is extremely flat, one of the flattest surfaces you can get for the money. When this annealed glass goes through the tempering or toughening process, it is heated red-hot and then quenched quickly. As the red-hot glass passes through the tempering furnace it can sag between the conveyor rolls causing what is known as "roller wave", and during the rapid cooling process this roller wave becomes solid. This can be seen on most if not all tempered glass if you look at a reflected image at a very sharp angle and slightly move your viewing angle you will see the image slightly distort or not track smoothly. If you see this distortion then you have tempered glass. If the image does not distort then it is likely annealed. I'm in the glass biz, and this is how i can tell if an unlabeled piece of glass is tempered or not. NEVER assume that if the edges are sanded that it is tempered.

That should be marked as a key post.

#137 3 years ago

"If you tap the playfield glass and do not hear a 'thump', but rather a 'tinkle and a rattle', you need to replace the glass."
- TBK

Old owners know what I am talking about here.
You use your ears.

You can also easily determine tempered glass via use of polarized optics from the the process that @bbreise was referring.
You use your eyes.

"Another way to identify tempered glass is to view the glass through a pair of polarized sunglasses. In many cases, viewing the glass in sunlight, through polarized lenses, will reveal dark lines or spots. These are prime indicators that the glass is tempered. The lines are formed by the machine rollers during the cooling process."

1 week later
#138 3 years ago

I'm guessing if there is a chip on the edge and it didn't explode into pieces it's not tempered?

20170118_192056 (resized).jpg

#139 3 years ago
Quoted from Mitch:

I'm guessing if there is a chip on the edge and it didn't explode into pieces it's not tempered?

That's correct. I also would NEVER use such a dangerous piece without the edges being finished - yuck.

#140 3 years ago
Quoted from Mitch:

I'm guessing if there is a chip on the edge and it didn't explode into pieces it's not tempered?

No, it can be chipped. It will usually fail if that happens, but not always. But take my advice carefully, I'm unverifed trash.

#141 3 years ago
Quoted from volcanodiver:

No, it can be chipped. It will usually fail if that happens, but not always. But take my advice carefully, I'm unverifed trash.

I will find out someday when dispose of it. It was badly scratched anyway and edges were a little sharp.

#142 3 years ago
Quoted from Mitch:

I will find out someday when dispose of it. It was badly scratched anyway and edges were a little sharp.

If your have polarized glasses just look at it in the sun, you'll see shadows patterns from the stress in the tempered glass.

But take my advice carefully, I'm unverifed trash.

#143 3 years ago
Quoted from Mitch:

I'm guessing if there is a chip on the edge and it didn't explode into pieces it's not tempered?

I have seen tempered glass with the kind of damage and not shatter. I have one in my Big Game with way worse than that going on for many years in and out of the game with no problems... yet

#144 3 years ago

I'm going to have to flush all my tropical fish and throw away my aquariums because they are made of dangerous non-tempered glass!

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