Tech Tip: Ring Around the Bullseye Part Two

In part one we discussed pressure rings. In part two we will discuss trapped air.

Trapped Air: Black, green or shiny, are terms typically used to describe the appearance of air trapped around the outside of the damage. While it may appear clear from one angle, inspecting from multiple angles will reveal one of the above tell tail characteristics of trapped air. Causes include:

  • Injector does not provide enough pressure to force resin to the outer reaches of the damage. Often this is not so much a sign of an injector issue, but a sign of an unskilled technician. If having this problem, contact the injector manufacturer immediately for assistance and proper use recommendation.
    • Not using enough resin.
    • Not getting enough resin into the end seal. When using a Delta Kits injector, most damage only requires a few drops of resin, but the resin has to be properly placed so it completely fills the end seal.
    • End seal not completely covering the impact point or otherwise leaking.
    • Blocked impact point. Rare, especially in a bullseye.
      • Drilling is rarely necessary. In most cases drilling is only required to terminate long cracks, provide an access point on damage where the impact point does not break the surface of the glass, when drilling large capped pits, or to drill into an air space after an improperly filled and cured windshield repair has been completed.
    • Too much pressure on the glass. A common mistake windshield repair technicians make is to apply too much pressure against the glass when attaching the injector.
      • Think of the injector seal as the gasket on an oil filter. If a quality seal is used there should be very little pressure required to create a leak free seal against the glass. In fact, over tightening can actually cause injector seals to leak and lose pressure.
      • Too much pressure against the glass forces the damage to close, leaving less air space to fill with resin, making it difficult to get resin to flow into the damage.
        • Technicians who use too much pressure against the glass commonly find that the damage will appear full until they remove the injector, but a dark ring of air will appear around the outside of the damage.
          • Many technicians result to curing under pressure but that is really only masking the problem instead of solving the problem. IT IS NOT NECESSARY TO PRESSURE CURE A PROPERLY EXECUTED WINDSHIELD REPAIR USING A DELTA KITS WINDSHIELD REPAIR SYSTEM!
        • Many windshield repair bridges are attached to the glass using suction cups. Suction cups have a great deal of flex in them so this type of bridge often requires a lot of pressure against the glass to counteract the flex in the cup. Delta Kits uses vacuum cups to attach the bridge to the glass so there is virtually no flex and very little pressure against the glass is necessary.
      • Not enough vacuum. This is a common misconception and is rarely, if ever, the case. Very little vacuum is needed to start the air moving to the surface.
      • Too much vacuum. Another common misconception is the more vacuum, the better. Too much vacuum will actually lift resin back out of the break and may pull air from any cracks that reach the surface of the glass.
        • Long cracks almost always reach the surface.
        • Star breaks and combination breaks often reach the surface.
        • Bullseyes rarely if ever reach the surface of the glass outside of the impact area.
      • Inefficient injector design. Injector is a closed system and has nowhere to exhaust air that is removed from the damage. As more and more companies have adopted “vacuum first” injectors, closed systems and the problems associated with them often make it difficult to remove all of the visible air from the damage.
        • Again, many technicians result to curing under pressure but that is really only masking the problem. IT IS NOT NECESSARY TO PRESSURE CURE A PROPERLY EXECUTED WINDSHIELD REPAIR USING A DELTA KITS WINDSHIELD REPAIR SYSTEM!
      • Inadequate technician training. While some people have a natural ability and produce professional quality repairs from day one with no assistance whatsoever, most technicians benefit greatly from some basic training. Unfortunately, some of the training that is currently being offered in the windshield repair industry is actually providing technicians with false information. The confusion over pressure rings versus air trapped in the damage is due in part to the fact that some of those providing windshield repair training do not understand the basic principles of how a windshield repair system works. Worse yet, they throw out words like “science” and “facts” without actually having any scientific facts to back their claims.

This concludes part two of our three part Ring Around the Bullseye series. In part three we will provide a short summary and a video showing a bullseye being properly filled, including air removal, with no pressure ring.


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