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Old 02-16-2012, 10:05 PM
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How to cut down your own windshield - Yup, you read it right!!

So, after much discussion and debate, I decided that it was more economical to cut down my own custom sized windshield. But how? So I found this video, and it was my starting point.
Thanks Pete for the start! So with that video studied, dissected, and studied some more, I started gathering supplies. I purchased the same Rotozip(@$60), but I think any similar rotozip-type router will do. After searching, I didn't find anything cheaper so I bought the exact 120 grit 1/8" diamond router bit, to the tune of $98. I stopped by a local windshield repair place, and the owner happily gave up 2 old windshields for me to practice on. Thanks to Action Auto Glass in Killeen! The last item Pete used was a coolant pump. Unfortunately, my military paycheck cant afford that $700 pump. However, in Texas the water in the pipes is still cold-ish, so I set up the garden hose on the top of the windshield (to run down the windshield), and cracked open the faucet about 1/4 to 1/3. Enough to keep a constant flow, but not too much to splash all over the rotozip. I hung the power cord up high, and made sure the router cord was up off the ground too. Then I just started. Carved off a few chunks to get a feel for it, surprisingly, it only took a few minutes. Then I started on this part:

Played with a lot of angles and grips. This is the best angle I found, shallower than 45 degrees

Also, you need to use the wide part, and make sure not to dip down too far to catch the skinnier part

One last thing about the grip. Make sure you hold it firm with both hands, be a little forcefull, but not to hard. If you are too light, the bit will skip around and crack the windshield. If you are too hard, the pressure will crack the windshield. Just listen as you cut, you'll hear the difference as you push harder or softer. Make sure you are using a sawing motion, the speed of your up and down motion is not a factor, as far as I can tell. Its just the forward pressure you have to watch.

Now the good pics.

Not cracked, its an etch line for me to try to follow!

OK, now this IS a crack. I wondered how forgiving the glass is, so moved the water away to see how fast it gets too hot and cracks. The answer is 0.0000001 seconds. Seriously, it was almost instantaneous.

SO there you are, its possible, you can cut down your own windshield. Glass dust, mist and little glass shards fly all over, i picked 3 shards out of my face! But as long as the cool water is flowing, you are good. Oh, and wear rubber boots and dish gloves, I was pruny after the 30 mins I spent on this little experiment.
Any questions, please feel free to post here or PM me!
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