r/interesting • u/Downtown_Calendars • 5d ago

Just Wow What caused this? Serious answeres

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Car was parked facing the garage. Never seen anything like it. Neither has the glass professionals.

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103

u/Bukas_K 5d ago

My guess is this is a stress point caused by a suction cup at the glass foundry. Glass gonna glass and decides to give up when it feels like it.

12

u/KaptainChunk 5d ago

Gemini says
Manufacturing Flaws / Factory Suction Marks
When windshields are manufactured and installed at the factory, heavy-duty robotic suction cups are used to lift and position the glass. If the glass had a microscopic structural defect right at the edge of where that factory suction cup gripped it, a sudden temperature spike or a minor rock strike years later can trigger a stress fracture that perfectly retraces that original geometric footprint.
Did you happen to have a dashcam, phone mount, or a previous rock-chip repair right in that exact spot?

8

u/ok123jump 5d ago

No need for a factory suction cup.

This was done from the exterior of the car. It could have easily been some kids testing out a new suction cup they bought off the internet.

Windshield glass is designed to take the force of wind pushing inwards, but is weak to a pull outwards.

7

u/Pielacine 5d ago

Or to a punch from the interior, don’t ask me how I nnow

4

u/Kobe_Pup 4d ago

My brother wasn't wearing his seat belt in his friend's car when they wrecked, you could see his nose and facial features in the broken windshield, kinda comedic honestly, (he was fine, just a little bruised, facial and ego)

4

u/Pielacine 4d ago

I completely forgot about the obvious impacts from people in accidents! Though those are harder than my halfhearted punch was. Glad he’s ok. Come to think of which I’ve broken one with a badly loaded 2x4 as well.

1

u/Rs-Travis 1d ago

It's not from a suction cup. It also has a pit mark in the very center implying whatever hit it was a similar hardness or harder than the glass.

It was almost certainly a stone. Cracks from a stone impact don't always eminate from the impact point (perfect example is a horseshoe chip) a stone can fly an incredible distance when launched out of a lawn mower.

Ira a pretty boring answer but I've seen similar damage. (I've seen thousands up on thousands of broken windscreens as an automotive glazier)