[JMSTOY]

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.
http://www.youtube.com/watch?v=pl5nm48pYFc
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!
Zak

[MARTINSR]

Damn impressed Zak, damn impressed!

Brian

[dinger]

Great post and we thank yopu. Post more please, I am wondering if a guy needs to work the edge after the cut for a smooth effect?

[nine4gmc]

sticky

i have a rotozip, now i just need to chop something so i have another reason to use it

[deadbodyman]

I've used a roto-zip for cutting outlets and lights when sheetrocking it makes a tight fitting box but when cutting you need to go counterclockwise so the bit hugs and follows the the outside of the box ..I'm wondering if if you tried changing direction to see if one way was easier to control the machine than the other...
I had a feeling you would pull this one off....

[Stu D Baker]

Looks as though you're on the right track. I've got all the stuff to do mine, just need to buy a windshield and maybe wait for warmer weather (no floor drain in the garage) so I can work in the driveway.

Thanks for the pictures. They give me some additional inspiration for my project. Stu

[JMSTOY]

Originally Posted by dinger

Great post and we thank yopu. Post more please, I am wondering if a guy needs to work the edge after the cut for a smooth effect?

Yeah I would say so. But not much, like Pete did in the video, probably just hit it with the sander a bit. Seems to me it would depend on how youre gonna mount it. Im goin to poly it straight in like a modern windshield, and add trim. If youre going to gasket it in old-school style, probably work it a little more. I'll post more, just trying to get down the technique and then keep practicing till I'm ready. If I mess up, it's a $150 mistake!
Zak

[JMSTOY]

Originally Posted by nine4gmc

sticky

i have a rotozip, now i just need to chop something so i have another reason to use it

Please don't tell your significant other I gave you the idea! My wife would kill you through the Internet if you gave me another idea like that! Lol

[white72gs455]

why wear rubber shoes if they have holes in them? LOL!

All of your socks must have polka dots by now!

[MARTINSR]

Originally Posted by JMSTOY

Any questions, please feel free to post here or PM me!
Zak

To hell with PMs! Post it here so we all can get something out of it.

Brian

[MARTINSR]

I just came back to look over this thread, DAMN it's impressive! This is like bending steel with your mind, Uri Galler stuff. It's like the "The Switch" on Seinfeld (click here)
Honestly, this is some awesome stuff!

Brian

[JMSTOY]

Today is rainy, but tomorrow is sunny and nice, so I'm going to step it up. I'm going to tape off a "windshield" out of the other practice windshield I got. Then I'm going to cut it down. Maybe only about 4 inches all around, so that I can cut it down again for more practice. Pics will be posted!
Zak
PS thanks Brian, appreciate it!

[rattlertrikes]

I started in the auto glass business back in 1962 and we didn't have roto tools. We cut down all our curved windshields with a sandblaster. It is much easier than what is proposed here, and the finished edge is smoother, and the risk of breakage is much less.

[JMSTOY]

Originally Posted by rattlertrikes

I started in the auto glass business back in 1962 and we didn't have roto tools. We cut down all our curved windshields with a sandblaster. It is much easier than what is proposed here, and the finished edge is smoother, and the risk of breakage is much less.

Not that I doubt you, but I would think the heat from the friction of the high power sand would crack it? I have read about that method though, I read mixed results. I went this route because the startup cost of sandblasting equipment, taping off my own booth, etc was way more than the @$200 I spent with the rotozip and bit.

[deadbodyman]

BTW,,,ANY router bits with a 1/4" shaft can be used in an air die grinder....if your worried about getting shocked.....I even have an 1/8" adapter to use dremel bits with my air die grinder when the need arises...