1. This technique does not meet Original Equipment specifications.
2. It leads to mixing of chemicals, some of which may be incompatible.
3. It allows the urethane surface to be contaminated by road dirt, cutout lubricants, Krytox, silicone etc. etc.
4. It provides the replacement windshield with a bed of cured urethane having the form (shape) of the previous windshield - which may be very different - thus contributing to stress and ultimately breakage of the replaced windshield.
5. Closecutting puts the replacement windshield too high to the body and the old adhesive may cause interference with moldings. Consequently, when the windshield is being pushed down into the adhesive (decking), installation breaks may occur.
6. Urethane cure and shrinkage is not consistent at different thicknesses, therefore, an uneven cut may place the glass into tension/stress resulting in breakage of the windshield.
7. When a cutout is being done on a windshield, the possibility exists of slicing the old adhesive several times at varying depths thus resulting in leaks and little or no adhesion in these areas. This compromises the structural integrity of some vehicles and possibly windshield retention.
8. Some forms of this procedure may reduce "land" area for fresh adhesives and thereby may lead to inadequate adhesive surface area. Again, this can compromise structural integrity as well as proper function of the windshield as a deployment device for the airbag.
9. There may be rust on the pinch weld area under the original urethane that may lead to leaking and loss of structural integrity in some vehicles' structural integrity as well as proper function of the windshield as a deployment device for the airbag.
10. Closecutting does not allow verification that a previous installation was performed using proper materials or methods.