When I was still new to windshield repair, I was called to do a repair. I followed standard procedure and some of the legs filled to perfection in no time at all. But there were a couple that would not fill at all no matter what I did. I applied more pressure, I backed off, I probed and I sweated... nothing I tried had any affect on them whatsoever. Finally it occured to me that maybe those legs were on the inside layer of the glass... and that is exactly where they were! Of course I had to give the client the bad news, and since it couldnt be repaired, I didnt get paid for the job, but it was a valuable lesson anyway. Now whenever I suspect that the break might go all the way through both layers, that is the first thing I check. Just scrape your fingernail, probe or razor blade across the line, and if it catches, the crack is on the inside.

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