Reducing Cold Weather Crack Outs


As the seasons change windshield repair technicians begin reporting an increase in crack outs. Rain and snow can certainly create challenges not faced in warm dry climates but understanding the primary cause of crack outs and adjusting your repair procedure accordingly will go a long way toward eliminating cold weather complications.

Moisture must be removed from a break in order to be properly repaired and the most popular way to remove moisture is with heat. However, heating a small area on a cold windshield too quickly may cause thermal stress and thermal stress may cause a crack out so how you heat a damaged windshield is critical to achieving a successful windshield repair.

In my opinion, the Delta Kits Moisture Evaporator is the fastest and safest way to remove moisture from a break prior to injecting a windshield repair fill resin. However, if the glass is cold it is extremely important to warm a large area of the windshield “before” using a moisture evaporator so let’s talk about warming the windshield first and come back to moisture evaporators in a minute.

Warming the Windshield

There are many ways to warm a windshield but my personal preference is to use a hair dryer mounted to the outside of the windshield using a Delta Kits Scorpion tool and a Scorpion Large Flashlight Attachment. Hair dryer sizes and shapes vary but most are typically easy to adapt to the Scorpion tool. The flexible arm of the Scorpion tool makes precisely adjusting the warm air flow across the break simple and best of all once mounted it is completely hands free.

Using Delta Kits Bubble Dome with a Scorpion mounted hair dryer additionally provides protection against rain, snow and ultra violet light. The Bubble Dome also keeps the injector and resin warm during the repair process. Just direct the warm air flow into the mouth of the Bubble dome to warm an area of glass 16” in diameter throughout the repair process.

If possible, running the vehicle’s windshield defroster will help maintain the temperature of the entire windshield. While preferable to warm the glass from the outside, warming from both the inside and outside reduces the time it takes to warm the windshield.

Using the Delta Kits Moisture Evaporator

Once the glass surrounding the area to be repaired is warm to the touch it is safe to use the Delta Kits Moisture Evaporator and immediately cooling the damaged area using the Delta Kits Heat Exchanger once the moisture has been completely evacuated.

Under no circumstances should any chemical other than a high quality windshield repair resin be introduced into the break. Doing so may cause irreparable damage to the PVB layer of the windshield.

Always warm the glass first and use extreme caution if using a heat gun or propane torch to heat the windshield or dry out a crack in the windshield.

Caution: Failure to follow instructions may cause damage. The Delta Kits moisture evaporator is designed to be used for no longer than 20 seconds at a time and only on warm glass. The temperature of the Delta Kits Heat Exchanger must be adjusted to within 20 degrees Fahrenheit of the glass temperature before using to cool the glass.

In my opinion, other than a high quality windshield repair resin, chemicals should never be introduced into the damaged area and electric blankets, propane torches and butane lighters should be used with extreme caution. Electric blankets absorb moisture making them heavy, messy and dangerous to use. They are not meant to get wet! Butane lighters have to be used from inside the vehicle and only heat a small area of the glass, while warming the glass from inside the vehicle

I have literally repaired thousands of windshields and can only remember a few times when I experienced a crack out. Of those few memorable occasions one can be attributed to applying cold resin to hot glass, one to applying warm resin to very cold glass, one to applying too much pressure against the glass, and a couple that just wanted to run as soon as I touched the glass.

That last point is something very important to remember. Rock chips often crack out if left unrepaired. Sometimes running the defrosters on a cold damaged windshield will cause a crack out and sometimes washing a car with cold water on a hot day will cause a crack out. That’s why we are repairing the damage in the first place so it’s unrealistic to think that a crack out will never occur during the repair process. That said, these incidents should be few and far between. If crack outs are occurring frequently there is a procedural problem that needs to be addressed.

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