Headlight Lens Crack

["Al Powell" <APOWELL@agcom.tamu.edu>]

About the only way to stop a crack from contuing is to stop-drill it 
at the end of the crack.  This means drilling a hole at the end of 
the crack, which distributes the strain in a circle (the hole) and 
sometimes stops it from spreading.  Of course, it doesn't remove the 
reason the crack started in the first place.

On a headlight lens, the thermal cycling from having that halogen 
lamp on and off would be likely to spell doom for an attempt to 
stop-drill....BUT you might get a diamond-tipped bit (or something 
similar - you have to drill glass, remember...) and try it.  Then you 
can use clear silicone to seal up.  Result: a faulty lens with 
silicone impairing the light pattern.  Yuck.

If you try something like this, be prepared to sacrifice the lens NOW 
instead of waiting for it to finish cracking on its own.

Igor, any comments?  You seem to be the most clued-in on ideas like 
this.  Am I leading the poster who asked this question astray???



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Al Powell, Ph.D.                 Voice:  409/845-2807
107 Reed McDonald Bldg.          Fax:    409/862-1202
College Station, TX 77843      
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