Hmmm.............garage door open.

You sure a critter didn't get it ? Fly or run into it.

LTG : )

Do you have an ex-wife.....that was my first thing that crossed my mind !!!

sorry man, i agree with LTG, there's gotta be a reason.

http://en.wikipedia.org/wiki/Spontaneous_glass_breakage

It's also possible that the glass was not in just right and the lock tongue was putting excessive pressure on the edge of the glass. It's pretty hard to break tempered glass with head-on stresses.

Big temperature change?

Karma?

?

th.jpeg

At least you had the playfield glass on when it happened and don't have to pick a million pieces of glass out of your game!

Holy crap! I blame Obama

It doesn't take any force/pressure on the edge of the glass to cause it to explode. Your backglass may have been in a slight bind.

Just a scratch in tempered glass can change the tension and have it explode.

As strong as tempered is for impact, there is no free lunch.

I had this happen to me with my Alien Poker machine. Only I had just put the head on the machine and slid the back glass in. I placed the back glass and the next thing I know.... there was glass everywhere.. i mean everywhere.. Im still finding specs of purple and blue here and there. My friend Mike was standing there was like WTF!?? It was almost like glass dust. The only thing I can think of is that it must have had a prior tiny crack somewhere prior to install.

well at least it was only a piece of glass and not a silkscreened one.

I just had my Guns N Roses backglass literally explode as I was cleaning it. The translite was off as it was just autographed by Matt Sorum so no damage there... Talk about a surprise!
Now the question is where is the best place to get a replacement backglass for the correct size and I would assume beveled edges (I can't remember now it's in pieces!)

Any glass place will get you one. The price on glass seems to really change depending on who you get it from, though.

Does anyone have the dimensions available on the Guns N Roses backglass and can recommend seller? I have no way of measuring as it's in 6000 pieces of glass dust.....

Maybe it was the difference in temperature since it is likely cold in the garage; 70 degrees inside the back box with the lights on and 40 degrees in the garage.

My pinballs are all in my basement at 68-70 degrees year round. I also have all LEDs in GNR so it's not running hot directly from the lights behind the glass. In fact, my glass hasn't been on the game for 3 weeks so there wasn't any temperature issue.

is it cold outside?

The good part is no one was hurt, and police force translights should not be too hard to find.

Thanks guys for sharing info & pics about this topic.

So far, I've not had to endure a spontaneously combusting backglass.

Had it happen to my Elektra backglass. just exploded in my hands as I was putting it back in. Still find the odd square of glass 3 years later.

I would say its a temperature issue i found some games stored in a unheated warehouse for many years and several of the backglasses were broken also a couple of the playfield glass were broken. Maybe from movement of wood ?

This is due to internal stresses and COE (Coefficient of Expansion) in glass with greater impurities. All glass is not the same and age and cumulative stresses can build up over time >> this is increased in glass that is not the optimal ratio of components when originally made or experiences large amounts of environmental stress.

Like Vid says a scratch can change the entire dynamics and shatter resistance of a piece.

More likely the spontaneous explosion is due to built up thermal stresses over time. The components in poorly made glass do not expand and contract in the same way/time when any amount of heat is applied or removed. Over years of some degree of continual thermal stress (like being in a garage where temperature fluctuates large amounts in short periods) the stresses can actually build up. Think of it like microscopic fractures and over time you finally hit a critical point of microfractures, then POP. It is science

(past life as a professional glass blower > both scientific and recreational)

i know a professional blower

All of what has been said is completely feasible. Tempered glass has stored energy. I had a clear glass Pyrex dish sitting on a Formica counter for about a week after it came out of the dishwasher, it suddenly exploded while i was in another room. A search on exploding Pyrex dishes turns up tons of events.

http://www.glazette.com/Glass-Knowledge-Bank-25/tempered-glass.html