Drilling glass

[mikey98]

I found a great tip on how to tell if you glass tank is tempered or not. Take two polarized lenses ether from a camera lens or sunglasses and put one on each side of the tank. Turn one of the lenses and hold the other still. If an X appears between the two lenses the glass is tempered. If the lenses just get dark then black it is normal glass. Also to break tempered glass you must put about 1500lbs in one spot. To break non-temperd glass you only need 400lbs. It is very easy to break tempered glass with sewing pin but much harder to break it with a baseball bat. Just some tips I learned and wanted to pass along. I will let you all know how my glass drilling experience goes. I hope to do it this weekend.

 

[danmhippo]

Yo, so are you drilling it by the sewing pin or the baseball bat?

 

[KanUCme]

OMG, he's gonna drill it... Mike are you nuking futs? Nah, good luck mike. Let us all know how it went, or call me I want to come watch this drilling in action!

 

[AnotherGoldenTeapot]

Well it's certainly very easy to drill ordinary glass - a "no risk" process.

I've done a few holes (more than 5, less than 10) in various pieces of glass of different age and thickness. It's so amazingly easy.

I've read that you can't drill tempered glass. I've never tried so I can't comment definitively. However, I don't see what you wouldn't be able to drill it. Maybe you just need to take it really easy as you cut through it?

 

[Anonymous]

DO NOT try to drill tempered glass. It just shatters.
(the main reason my 100 gal has a new bottom. They guy who had it before tried to drill it.

B

 

[KanUCme]

What exactly is "tempering"?

 

[Anonymous]

Right - tempered glass CANNOT be drilled no matter how "easy" you go. Drilling normal glass is a simple process.

Many tank bottoms are drilled and tempered. They drill the holes prior to the tempering.

 

[MattM]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by KanUCme:
<strong>What exactly is "tempering"?</strong><hr></blockquote>

A process to strengthen the glass. Either it is done with very high temperature, or a chemical process where the glass is dipped in potassium nitrate at about 450 degrees C.

In either case, it causes the molecules at the glass' surface to compress making the glass harder and stronger, but also building in mucho stress. It takes a lot more force to damage tempered glass, but when it does get damaged (like by an attempt to drill or cut it), the internal stresses are all realeased at once and the sheet of glass literally explodes leaving no piece larger than about 1/4".