Automotive safety features have evolved immeasurably over the last century, in both structure and function. Windshields are key structural safety elements, and as such are no exception. They are designed to support the front part of the vehicle if it rolls, and not to shatter into harmful shards on impact.
The technology used in auto glass repair has also evolved and improved, with the invention of newer, clearer and stronger materials. Cracks and chips can generally be repaired, if they are caught before they get too big or run too far. There are also kits available for do-it-yourself repairs, but these come with certain complications that make a compelling argument for getting the job done by a professional. This is because the resins used to repair cracks and chips come in different types, and not all react the same way, or should be used for the same purpose.
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Resins used for auto glass repair work are manufactured to fill in an area where glass is missing, adhere to the surrounding glass, and provide structural support to stop the surrounding glass from cracking further. Resins are used because they are clear, flexible and yet durable.
High quality resins will last a lifetime, whereas poor quality resins become brittle and ineffective quite quickly. Some low quality resins do not harden correctly, and some harden too much and crack under pressure.
Not all resins were created equal, and so it is important to use a high quality resin for an auto glass repair, as this is a safety feature of the car, and it needs to hold up under constant use, in all weather.
Viscosity
Resins come in different viscosities or thicknesses. Viscosity is measured in centipoise (cps). The higher the viscosity, the thicker the substance. For example, water has a viscosity of 1-5cps, while honey has a viscosity of 2-3000 cps.
Resins of a higher viscosity may take longer to cure or harden, and certain types of resins will have an ideal temperature range in which they should cure.
An auto glass repair professional should know which viscosity to use for the type of damage she is asked to correct, as resins for glass repair are available in 20, 40, 60, 90, 100 and 200cps. This is why technicians cringe when people suggest using nail varnish to repair a crack.
Different Fixes
As with anything in life, it may look simple at first, but on closer inspection, auto glass repair is never a simple job. Professionals classify windshield damage into various categories by shape, size and depth.
To the general public, a windshield can have a crack or a chip, but within the automotive industry, these blemishes are described in terms like bull’s eye, combination break, edge crack, floater crack, pit, stress crack, half moon, long crack and star break.
Not all of these can be corrected. If they are larger than eight inches, the windshield usually needs to be replaced. However, a knowledgeable and experienced technician will be able to determine the safety value in a repair, and will often have a couple of tricks up his sleeve when it comes to the repair job itself, what resin to use and how to use it.
UV Protection
Once a crack or chip has been repaired, and the resin has been allowed to harden and cure under the sun, a professional auto repairer will buff down the resin and coat the area with a type of varnish which is designed to protect the resin from the ultra violet rays of the sun. This is because exposure to UV rays after curing can cause resins to perish and become brittle, and the resin will lose its flexibility, causing the screen to start cracking again.
Windshield glass is also manufactured with an integral UV shield to protect passengers and the vehicle interior from harmful UV exposure over time. It makes sense to add in a form of UV protection to an area which has become vulnerable, although not everyone might think of it.
High Tech, Not High Cost
Many people believe that doing the job themselves will save money, but if the job has to be done twice, then it may be a case of false economy. Especially when dealing with a safety feature like a windscreen, and complex chemical compounds like resins, it might sometimes be a better choice to let the professionals handle it, and know that the job has been done well. In the end, this kind of consideration always comes down to money, especially in the current hard economic climate, but sometimes less really is more.