Determining if glass is tempered?

[mykidsclownfish]

I recently pick up a 46 bow front on craigslist. the bottom glass has a sticker that says the bottom in tempered, but does not mention the sides. Is there an easy way to determine if glass is tempered? i would like to drill the tank for overflows and returns but dont what to screw things up if the glass is tempered.

 

[Usctom]

You can use a mirror and polarized glasses. When looking at the reflection off of the mirror there will be diamond shapes if the glass is tempered.

 

[shovelrider]

If you use polarized glasses and look at the glass in the sun you will see a pattern if its tempered.
Most tanks are not tempered on the sides, just the bottom.

 

[redfishbluefish]

You use polarized sunglasses and a white screen on a phone or laptop. Turn the white screen until it goes to black. If it is solid black, the glass is not tempered. If it has streaks of gray to white, it’s tempered.

HERE’s the actual link.

 

[mykidsclownfish]

great, i will try that with my fishing glasses, thanks