How to gradually warm the glass in the middle of a “Polar Vortex”
As this brutally cold weather sweeps across the nation there are multiple things to consider when performing a cold weather windshield repair. In this article we will focus on the temperature of the glass and temperature of the resin.
Temperature of the Glass
Glass contracts and expands as the temperature fluctuates, which is why it is so important to GRADUALLY warm the windshield before attempting a cold weather repair. If the glass expands or contracts too quickly it can lead to crack-outs. Pouring hot water on a cold windshield for instance, is very likely to cause a crack out. A hair dryer, the preferred method for warming from outside the vehicle, should be set to low heat until the glass begins to warm up, then can be switched to high heat as necessary to achieve and maintain the proper temperature throughout the repair process. Consistent temperature control is important and can easily be achieved using the Delta Kits Scorpion Flex Tool holder to properly position the hair dryer while keeping both hands free to carry out the repair process. A variable temperature heat gun may also be used following the same precautions to keep from heating the glass too quickly.
A common misconception is that using the defrosters on high heat to warm the windshield from the inside heats the glass too quickly. While heating from the outside is preferred, in extremely cold temperatures it can be beneficial to use the defrosters to help maintain a constant glass temperature throughout the repair process, especially when used in conjunction with the use of a hair dryer from the outside. If the vehicle has been running immediately prior to starting a windshield repair, the defrosters have likely already been run on high heat to keep the glass from fogging so you can continue to do so as you complete the repair. If the vehicle has not been running immediately prior to starting a repair, the defrosters will blow cold air at first, then slowly warm up as the engine temperature rises, so starting with the defroster on high heat is perfectly acceptable.
Regardless of the method used to warm the windshield, the temperature of the glass should be brought as close as possible to the Delta Kits recommended temperature range of 70-100 degrees Fahrenheit (21 to 38 degrees Celsius), and that temperature should be maintained throughout the repair process. Covering the area to be repaired with a Delta Kits bubble dome and directing warm air inside is an excellent way to achieve and maintain the correct glass temperature in nearly all conditions. Using a Delta Kits Infrared Thermometer to monitor the temperature of the glass both before and during the repair process takes the guess work out of maintaining the proper glass temperature. If you do not have an infrared thermometer, carefully place your hand against the glass, if the glass feels cold to the touch, it should be warmed before proceeding. If the glass feels too hot to touch comfortably, it should be allowed to cool before proceeding.
Temperature of the Resin
When executing cold weather repairs it is also crucial to consider the temperature of the resin you will be using. It is important not to inject cold resin into warm glass, or warm resin into cold glass, this may also lead to crack-outs. Store resin at room temperature if possible, and allow the windshield to gradually reach the recommended temperature range to achieve optimal results and to avoid crack-outs. If resin is exposed to freezing temperatures it may freeze or thicken depending on the length of exposure. If this happens allow the resin to reach room temperature before attempting to use.
Important: The glass and resin temperature should be within 10 degrees Fahrenheit (5 degrees Celsius) of each other to minimize the risk of thermal shock when the resin is injected into the glass. Cold resin can be warmed with a hair dryer or the defroster as the glass is being warmed to achieve an acceptable temperature range. Do not put resin in a shirt or pants pocket to keep it warm. If the bottle leaks resin could come in contact with skin.
Lastly, layer up and STAY WARM!
For additional tech tips and more information on repairing laminated glass, visit
Deltakits.com and see our helpful informational videos, or give us a call at (800)-548-8332.