Are Super Soaker water guns powerful enough to crack a windshield?

Dear Car Talk

Dear Car Talk | Nov 01, 1997

Dear Tom and Ray:

A week ago my 11-year-old son and his friend came running into the house to
inform me that my 1989 Dodge Caravan had mysteriously developed a crack right
down the middle of the windshield. They excitedly announced their discovery
while holding their new Super Soaker water guns.

If you don't know what a Super Soaker is, the name says it all. These toy guns
can propel a considerable amount of water about 25 feet -- fully soaking the
intended target. I went out to inspect the damage and noticed water splattered
across the windshield and onto the hood of the Caravan. It was about 85 degrees
out that day, and the van had been sitting in the sun all morning. The van was
warm from the sun, but not hot. The water was cool tap water, but not cold.

The two boys admitted to having accidentally gotten the van a little wet while
playing, but they swore they did not intentionally aim their weapons at the
windshield (yeah, right). I have two questions: 1) Do you think these Super
Soaker water guns are powerful enough to crack a windshield? and 2) Would your
ambulance-chasing lawyers at Dewey, Cheetham & Howe represent me in a product
liability case against the Super Soaker's manufacturer? -- Bill

RAY: To answer your second question first, Bill, absolutely not. We've had many
wonderful water fights with Super Soakers around the office, and we would hate
to see them go out of business -- even if my brother did totally soak our tax
returns back in '89.

TOM: As far as your son's guilt or innocence, I would have to find him innocent,
Bill. It's extremely unlikely that the force of the water gun would be
sufficient to break a windshield. A fire hose might. But a water gun -- even a
good water gun -- would be hard pressed to cause a crack by itself.

RAY: The other possibility to consider is the temperature differential. If the
windshield was really, really hot, and the water was really, really cold, and
you really soaked the windshield with it (more than just a passing squirt), you
might cause a temperature stress crack.

TOM: But that's also very unlikely. If hot windshields cracked every time they
came into contact with cold water, we'd have windshields cracking every time
there was a flash summer thunderstorm or every time some guy turned the hose on
his car to wash it on a Saturday.

RAY: The most likely scenario, Bill, is that there was some small crack or chip
in the windshield to begin with. You may not have noticed it because it was tiny
and/or down at the bottom of the windshield where the glass meets the hood
(that's where pebbles and road debris tend to hit the windshields on these
minivans). And when you have an existing crack -- even a small one -- it doesn't
take much to make it spread across the whole piece of glass.

TOM: So "the last straw" could have been the pressure of the water gun, the
temperature difference of the water, or it could have been nothing at all.
Sometimes those cracks just decide it's time to spread out!

RAY: So the kid's innocent, Bill. But we'd recommend you take the Super Soaker
away for him anyway. He won't do any harm with it. But think of all the fun YOU
could have.

* * *

TOM: Does slamming the car door really make a difference to the life of your
car? Should you "save the brakes" by shifting into a lower gear to help you slow

RAY: You'll learn the surprising answers to these questions, and more, in our
pamphlet called "Ten Ways You May Be Ruining Your Car Without Even Knowing It!'
TOM: It's our guide to making your car last forever.

RAY: Become an instant know-it-all. Order your copy by sending $3 and a stamped
(55 cents), self-addressed, No.10 envelope to Ruin No.1, PO Box 6420, Riverton,
NJ 08077-6420.

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