Easy way to tell tempered glass from non tempered when the label has been remove

[Rudy00]

Uh oh i'm increasing becoming more interested in salt... the fact that it has to be done slowly really appeals to me and the amount of DIY sump, refugium and plumbing.  Its drawing me in!!! i think i've come down to either FW high tech planted or a salt tank

I've been doing lots of reading and have tons more to do but i'm getting the bug for this... ugh

but to my question: does anyone know of any sure fire ways other than the oh so important label informing if the glass is tempered or not for drilling purposes?

thanks

[darkdep]

If it's a fairly new tank and you know the manufacturer, you can consult with them.  Perfecto tanks, for example, are routinely made with tempered glass on the bottom and regular plate glass for the rest; so you could drill anywhere but the bottom.

Other than that, I don't believe there is any easy way to tell.

[rockgarden]

I haven't encountered any commercial tanks with tempered glass for the sides but as Chris has said, there are many tanks manufactured with tempered glass in the bottom.

Home made tanks are a different story.  I use whatever inexpensive galss that I can find when in one of my do-it-yourself moods.  Often, my home made tanks have tempered glass for bottoms and sides but not ends because they are made from discarded store shelving and that is always tempered glass for customer safety.

In answer to your original question, yes there is a way to tell because tempered glass often has a small indentation near one of the corners of the plate but just because you can't find that mark doesn't guarantee anything ....

Drilling newer tanks through the sides is normally not too much of a problem for those who are experienced in such things (I'm not) but older tanks can sometimes be a bit more tempermental since glass is actually a stiff liquid and gets more brittle with age. Some of my tanks are twenty or more years old.  Drilling them might be possible but I certainly wouldn't want to try. 

Ron

[luker78]

There are actually a couple ways to tell if the glass is tempered or now.  The first on is to touch it.  Rub your hands on glass that you know is not tempered then rub the aquarium glass.  There is a difference to the touch.   The other way to actually look through the glass.  Tempered glass will show more relections than normal glass.

Hope this helps.