Tempered?

[wesleyclement85]

How can I tell if glass is tempered? I have a 220 gallon tank. 3/4 inch thick glass and I'd like to drill the bottom for corner overflows but I don't know if it is tempered or not.

 

[CodyRVA]

Use polarized sunglasses and a screen (smart phone, tablet, laptop, etc). Basically, place the device inside the tank facing out (towards you/glasses). Device must be illuminated, I usually open my web browser to a blank tab for a full white screen. While holding the glasses on the outside of the tank, look through them, at the screen, then rotate the glasses. If you see gray lines or an obstructed view, its tempered. If it stays clear then its not tempered and you can drill it.

 

[wesleyclement85]

Use polarized sunglasses and a screen (smart phone, tablet, laptop, etc). Basically, place the device inside the tank facing out (towards you/glasses). Device must be illuminated, I usually open my web browser to a blank tab for a full white screen. While holding the glasses on the outside of the tank, look through them, at the screen, then rotate the glasses. If you see gray lines or an obstructed view, its tempered. If it stays clear then its not tempered and you can drill it.

Thanks. About to headed to walk mart for some new sunglasses

 

[TheEngineer]

Learn something new everyday. That's an awesome trick!