Replacing the tiny rear view mirror that sits on the cowls of our Cobra with a high quality OEM night-sensitive convex mirror is not nearly as difficult as you might imagine. First, you have to find just the right mirror. It has to be optical grade first surface reflective and ground to allow just the right amount of light to pass through the mirror itself (which helps with night driving) and it can't be too convex or not convex enough. Then all you have to do is disassemble your old rear view mirror, cut the new glass mirror to just the right size, then reassemble it all without breaking it. Piece of cake.
Over the last few months I've bought half a dozen or so different mirrors, all with different curvature of radius values (which is how "convex" it is) and different optical quality. I ordered some nice 3000mm radius curvature glass from Japan, but that wasn't convex enough and the Longacre Racing Mirror glass was a little too convex for my liking (but not terribly so and you might find you like it). Finally, I found the OEM General Motors replacement glass for the lower outside passenger towing mirror on the C/K Pickup that you got with the towing package. Beautiful first surface mirror, just the right curvature radius, and it is optically tuned to allow light to pass through it. Plus it doesn't have that pesky
"Objects in the mirror..." message since it was for towing and skirts those regs. Just the quality of the image compared to the cheapo mirror that comes with our cowl mirrors was astonishing. Now to cut it...
At first I tried a traditional glass cutter where you score the mirror, run the score and then snap it apart. That resulted in me buying more mirrors.
Don't even try a glass cutter unless you have some sort of super human skills. Instead, go straight to the Dremel Diamond Cutting Wheel #545 and punch a pin hole in a plastic water bottle so that it "pisses" a stream of water out the hole. Do not use the diamond wheel dry. Aim that stream of water right at your glass as you cut it with the wheel.
Voila!
Figuring out how to take a picture of the original mirror, and the new mirror, so you could see the difference was not easy. Here's a pic that gives you the orientation of looking at it while in the car and a fence as the image. The second pic is just to show you how clean the cut is (that mirror is the first one that broke when I tried to use a glass cutter on it).
Here's the new mirror assembled in the original frame, which could stand a little touch up with flat black paint.
