Warming the Glass
All techs have been there, making a bad weather windshield repairs. When performing repairs in cold weather, be sure to warm the glass and remove any moisture from the repair. The optimal glass temperature range is between 70 and 100 degrees Fahrenheit, and Delta Kits recommends keeping your resin temperature within 10 degrees of the glass temperature, so when doing repairs in the 35 to 70 degree range, be aware that it may take longer for the resin to flow into tight star breaks and cracks. The best practice is to warm the glass and the resin to the optimal temperature range whenever possible. Ideally, bringing the vehicle indoors is best, but not always practical. Using the vehicle’s defrost and a hair dryer to warm the outside of the glass are also good options.
Make sure to check for moisture. Carefully flex the break with your probe and look for moisture movement. If there is water within the break, remove it for a successful repair. Removing the moisture from a break takes as little as 20 seconds using a Delta Kits moisture evaporator, and the glass can be returned to ambient temperature in as few as 60 seconds using the Delta Kits heat exchanger. The tutorial video below explains how to check for moisture in rock chip damage and demonstrates how to properly remove the moisture before executing a repair.
Is the crack volatile? How long has it been there? Is it moving?
If there is moisture in the crack it has to be removed, and the best way to do that is with heat, so although I prefer not to submit long cracks to drastic temperature changes I do heat cracks to remove moisture. The important thing to remember here is that you want to warm the glass slowly, and if at all possible warm the entire windshield. Once the glass is warm, concentrate a heat gun tip or torch to dry out the break. CAUTION: This is not for the faint of heart. As most of you know I am not a big fan of using a torch or heat gun on damaged glass, but when it comes to long cracks moisture evaporators just don’t always cut it. However, using a torch or heat gun greatly increases the chance of a crack out, so I strongly suggest that you only use those methods if you have practiced this technique at least a couple of dozen times. Bad weather windshield repairs can be tricky.