Glass and Mirrors - Cutting A Large Mirror

Hi, I see we have some great glass experts here... I have read most of the mirror cutting posts, but I am a first timer and I want to know how to do this....

I got a fairly thin piece of mirror, probably 1/8" thick. It was about 36-40" wide and maybe 70" long, but while I was moving it, maybe due to a scratch, about 2 feet off one end just broke off and of course, shattered spectacularly all over the garage floor. Anyways, so now I have a 3' x 4'+ piece, of which one side is slightly concave form the breakage and not very smooth near the edge.

I want to cut off this concave part and make a rectangular piece about 3' x 4'. (btw I do wana do this myself because 1, I dont really care too much if I screw up, and 2, it would be much more of a hssale to lug this peice that weighs like 50 lbs to any glass store) I understand I should get a glass cutter, but does any do? I see some for like $4 at Home Depot, and some at Ace, so I need some advice on what cutter should I get specifically for this project.

Then, I read that you just "cut" the mirror on the front side in a straight line with a straight edge, but, I am confused because in a 3'+ long cut, isnt that hard to keep it a straight line? I dont think I have any straight edge that long, although I do have a yardstick, but even when I find something you may suggest, how do I secure it to the mirror so it doesnt move while I am cutting it, because if I mess up the line, dont I end up messing up the whole cut?

After making the cut, I simply what, apply pressure to the little half and "break" it off? The other factor here is that I only want to trim off maybe a couple of inches, so then, how do I grip it properly to apply enough pressure; do I brace it somehow, do I need a vice with soft pads... etc.., I am clueless...

Also after all this is done, what is the best way to polish the edges? Can I just take some specific rated sandpaper and sand off the edges and then buff it with a cloth? I want it to look nice, and safe with no hard edges, so any suggestions would be appreciated, whatever works. Apologies if this is too lengthy and demanding, but at the worst, hopefully this thread can be used as the father of all threads for cutting mirrors, ha.... ...
Thanks again

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Yes, I have the same question.
How do you cut a mirror?
Details, please.
Thanks.

First of all, mirror or glass is cut exactly in the same way. Try this website for some basics. Practice on some scraps of glass. If you have any questions after trying it, I'll be happy to give you more information.

http://www.homestore.com/HomeGarden/HomeImprovement/HowTos/HowTos/CRHO_CuttingGlassAndRigidPlastic.asp?poe=homestore

You asked alot of really great questions.... Hope this helps you:

To cut mirror or glass you will need a few things to do it properly.
A glass cutter.... a plain cheap one will work fine. You should also have a little dish of oil or kerosine to use with it when you get ready to score the glass. You just dip the tip of the cutter into the oil, and start scoring. This helps make a cleaner score line, and helps the cutter.

If your only cutting off two inches, gripping with your hands may be kinda hard. But since the cut line will be long. But the better the score line is, the easier it will be. Also make sure the surface of the mirror is very clean!

IF there happens to be a stained glass supply/sales store near you.... you may want to also buy a pair of "running pliers". These are just a pair of pliers that you place at one end of the score line and apply pressure. They will cause the glass to break along the score line that you have made. If the glass is clean, and your score line is good.... the glass will just pop apart at the score like magic.

If it doesn't work like magic..... and it stops partway down, just put the pliers at the other end of the score, and do it again.
If it breaks with jagged edges on the side of the score that your cutting off... you simply take a pair of regular pliers, (or special made "grozing pliers"), and kinda just nibble away the unwanted areas.

Smoothing the edges..... to smooth the edges a grinding stone is used. This can also be purchased at a stained glass store. It just looks like something you'd sharpen a knife with. And you use that to sand the edges smooth.

Also.... anytime you cut a mirror, you need to seal the edge to prevent the backing from peeling off later. What you use is up to you. They make special products for this. But some people just use things like clear nail polish.

If you have ANY questions or concerns curiosities..... let me know. We do stained glass as a hobby, and I'm glad to help.

Oh, and to score a straight line...... my approach would be to rig up some sort of template type thing. (Not sure how to describe what I mean here). But fix the glass on your table/workbench where it wont move by maybe a couple pieces of wood strips to kinda "frame" around 2 sides. Then use another strip thats a few inches longer than the glass, (for your guide), along the top-but where it wont put pressure on the glass. (Like a little bridge over the glass). And use something as spacers at each end of this guide... probably like 1/4 plywood scrap or something. This would let you just slide the glass into place, and score your line along the guide.


Please let me know if this info. helps. And you may also want to check out http://groups.msn.com/heartofstainedglass I'm a member of this site, and these people LOVE to help out. So let us know how it goes.

-Zel