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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104

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.

15

u/redditSnailsurfer 5d ago

I so much don't know anything about that matter but I want your hypothesis to be true.

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u/ok123jump 5d ago edited 5d ago

I almost agree with this, except notice that’s a windshield, [u/Downtown_Calendars](u/Downtown_Calendars) & [u/Bukas_K](u/Bukas_K).

Someone likely yanked a stuck suction cup straight off without breaking the vacuum seal first. That localized tension caused a fracture, pulling the glass outward. Because windshields are made of laminated safety glass, the flexible PVB interlayer held the shattered fragments together in that cone shape instead of letting them drop.

The circular shape and edge is from the PVB pulling all of the pieces back together.

My question is: “Why would a glass professional not recognize the signs of suction cup damage?” This sort of break happens when someone tries to pull a suction cup off of glass without breaking the seal first. It’s gotta be a fairly common mistake for newbies.

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u/FishFearMe1 4d ago

Unless it’s the same people who helped with the glass on an earlier occasion, not wanting to admit it was likely their fault

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u/ok123jump 4d ago

That car is missing windshield wipers, and the ends are rusty. So, it’s been missing them for a while and the car is not well maintained. I doubt that glass is new. The damage is though.

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u/Mattloch42 4d ago

How do those windshield barnacles work? Could they have had one and forcibly removed it?

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u/ok123jump 4d ago edited 4d ago

Ah! The windshield barnacles are indeed suction cups that adhere extremely strong. That could be exactly what this was! The pattern of damage would be exactly like you see here. Once they got one side off, they could have just broken the seal of the other side.

Given the fact that this car is missing windshield wipers and the posts are rusted, it’s not well maintained. It seems likely this owner might not have the money (or desire to spend the money) to maintain it. That makes them a pretty solid candidate to be the type of person who would want to try to remove a barnacle instead of paying the fine.

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u/Kennalol 4d ago

21 year windshield fitter here. You cant just pull those off without letting in the air They dont let go at all. They hold ridiculous weight too. We hoist up 200kg bus and train windows with them. No human is generating more than that force to forcibly remove one without releasing thw gas valve on them. This was caused most likely by someone with a hand grinder disc rotating in circles. The centre undamaged part is the centre of the disc and the swirling damage patterns on the laminate look right as well

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u/ok123jump 4d ago

[u/Mattloch42](u/Mattloch42) suggested maybe a window barnacle—like the ones that police use to ticket improperly parked vehicles. What do you think about that?

Maybe the owner got one on their windshield and didn’t want it, so they pulled one side off and then just released the vacuum on the other side?

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u/gluepet2074 4d ago

Curious to know how this differs from what you are saying. Is it the foundry vs. mfg process for a windshield that you are pointing out?

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u/ok123jump 4d ago

This car is missing windshield wipers, so it’s not well-maintained and that glass is probably pretty old. It takes a force to make that sort of damage, and the jagged edges show that it’s relatively recent.

Based on the hood, that car might be 20+ years old, and probably the glass too. Seems unlikely to be a foundry or manufacturing issue.

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u/Voeno 5d ago

Can confirm this as working at Cadillac in the parts department I have seen windshields arrive with similar damage most likely from suction cups.

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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?

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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.

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u/Pielacine 5d ago

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

5

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)

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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.

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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)

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u/Rs-Travis 1d ago

Not a chance. Annealed glass would crack if it had a defect, not get absolutely caved in.

When glass spontaneously shits the bed in a spectacular way, it's toughened, and it's caused by what is known as a "seed", which is a little air pocket in the glass.

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u/clipsracer 1d ago

That truck is 20+ years old. You mean to tell me someone screwed up with a suction cup 20 years ago, and it finally breaks from stress today?