WHEN NOT TO REPAIR
A good repair technician should be able to repair 90 percent of the breaks he encounters successfully. What about the other ten percent? These are repairs that cannot or should not be attempted. Recognizing these before hand saves a lot of time and aggravation. Examples of these breaks fall into the following categories:
Size Stars, bullseyes and combinations larger than a half dollar. Some technicians limit them to the size of a quarter.
- Position Breaks in the so-called "critical area." This is subject to interpretation.
- Inside layer of glass This is deemed unsafe, and is not recommended.
- Previously repaired breaks Sometimes these should be classified as previously "attempted" repairs. In some cases, the previous repairer will have done a poor job and not gotten enough resin in the break to prevent it from being re-entered and re-repaired.
- Stress Cracks: These are usually caused by improper installation of the windshield or wracking of the vehicle's frame, probably from an accident. If there is no sign of a rock chip associated with the crack and/or you know that the vehicle has been involved in an accident, you may be wasting your time and risking your reputation by doing the repair. Unless the underlying cause has been remedied the crack will open up again.
- Contamination: Most small cracks can be cleaned out and a satisfactory repair completed. Others will be unsatisfactory, but you won't know until you try. Water is the most common contaminant, and the easiest to remove. Test for liquid in a break by flexing it and watch for the lines to alternately disappear and reappear. Water can be removed by using heat, alcohol, vacuum, or a combination of those. Solid contaminants, such as dirt and bits of glass, can usually be removed by picking or blowing it out of the pit area. Use eye protection while doing this.
- Long cracks almost always surface after three or four inches. Eventually they will become contaminated with dirt and road chemicals. At this point, in my opinion, they can be cleaned out. Some technicians claim to be able to remove contaminants from long cracks by spraying or injecting solvents into the cracks. We have tested all of the products we are aware of and have found very limited success. Therefore carefully examine a long crack for contaminants prior to repair.
- Unknown contaminants You may be baffled by a break that will not fill, no matter what you do. There is a good chance that there is a silicone product in there, such as RAIN-X. Another possibility is that some one has pulled the "old transmission fluid trick," letting transmission fluid seep into a ding to make it less noticeable when selling a car.
When you run into one of these unsolvable problems, don't waste your time or lose confidence in your ability, just move on to the next job.