Question:

Is it advisable to repair a long crack without drilling the ends?

Answer:

Long cracks can be very unstable and should be anchored to achieve the best results.  The risk of the repair failing increases considerably if you do not take this cautionary step. The process is simple, though we would recommend practicing on sample glass if you have never drilled or are uncomfortable drilling before attempting it on an actual repair. This video demonstrates the process of anchoring.