The windshield is a huge part of a car’s structural integrity
Calgary is one of the windshield replacement capitals of Canada.
For that, we can thank the combination of frigid winter temperatures, warm Chinook winds, and the salt and gravel mixture that’s spread on the roads.
In this city, according to the City of Calgary website, when road surface temperatures are between 0 and -10C, salt is used to melt snow and ice. When road surfaces are below -5C, a sanding chip mixture (three per cent salt and 97 per cent fine gravel) is distributed.
While it’s great for traction, that fine gravel usually ends up equaling plenty of bruised, chipped and cracked windshields.
Mason Aiello is the general manager of Calgary’s CalAlta Auto Glass. The glass company opened in the early 1980s, and it’s been family owned and operated ever since.
With winter driving conditions just around the corner, we spoke to Aiello to get a better understanding about auto glass and its importance in the modern automobile.
“The windshield is a major structural component of a vehicle,” he says. “It supports the cabin by 45 per cent and it allows proper deployment of air bags.”
With that kind of structural integrity, a windshield has to be glued in place with a strong bonding agent, in this case, special urethanes designed for just such an application. Before the advent of air bags, windshields were simply held in place by a rubber gasket or butyl tape.
“The gluing process is where a lot of things can go wrong with windshield installation,” Aiello says. “The windshield has to be cleaned of all contaminants and the vehicle properly prepped for the adhesive.”
When removing an old windshield, Aiello says even the best technician will likely create some small scratches in the paint where the glass bonds to the metal. These scratches, if left untreated, will eventually start to rust – and they’re in an area where a vehicle owner is unable to see the oxidization.
“It’s very important that those scratches are primed before a new windshield is glued back in place,” Aiello says. “Otherwise, the rust that starts to form will affect the overall structural integrity of the vehicle.”
A windshield is essentially two pieces of glass sandwiching a plastic layer – hence the term laminated safety glass. While a stone or other piece of debris hitting the window will likely cause a chip, bruise or fracture, the laminated glass should not break into sharp pieces that could cause harm to vehicle occupants.
“Rock chips the size of a Toonie or smaller, or cracks less than 12 inches long — as long as the breakage doesn’t go to the edge of the window — can most often be repaired,” Aiello says.
And when Aiello says ‘repaired’, he’s speaking about restoring the structural integrity of the windshield. The process of sealing a chip (where an acrylic epoxy is forced into the cavity to bond the glass layers together again) does not mean the damage simply disappears — although some visibility is restored, some evidence of the bruise will ultimately remain.
It’s important to have chips sealed, because once moisture enters the bruise, colder temperatures will freeze the water and help spread the damage.
“I encourage people to keep a roll of Scotch tape in the glove box,” Aiello says. “If a rock hits the glass, put the tape over the chip before it gets wet.”
Beyond the obvious chips and cracks, a windshield will over time become pitted and worn. If you run your hand over the glass and it feels like sandpaper, it’s time for a replacement.
“Usually by that time, though, a driver’s visibility will be impaired – when they drive into sunlight they’d be completely blinded,” Aiello says.
Aiello concludes with a couple of winter windshield tips.
“When it’s really cold out, turn the defroster vents on immediately so you’re blowing air that’s the ambient temperature onto the windshield instead of blasting hot air – with the defrost you’ll gradually warm the glass.
“And, try to avoid entering a hot car wash when it’s cold out, because the sudden temperature change could crack a windshield.”
Article Source: http://driving.ca/auto-news/news/on-the-road-cowtown-chips
By Greg Williams