Drilling glass

[whaase]

I know this may have been asked many times, but, is there a way to tell the difference between regular glass and tempard?

Walter

[muck]

Yep. Try drilling it... You'll find out soon enough...

[whaase]

Everyones a smarta$$

Walter

[rusty]

Tempered glass has been heat treated to make it stronger but when they do that it also makes it brittle when you chip or try to cut it. I believe it has something to do with surface tension. If you have a raw piece of glass look at the edges if the have been ground or rounded off it is a good indicator that it is tempered.Also quite often but not always, they will put a sticker on it indicating that it is tempered. Hope that helps

[Rikko]

Contact the manufacturer of your aquarium and ask. Generally any standard tank under 30 gallons won't be tempered at all. Any larger and some brands and sizes begin to have tempered bottoms. All-glass and Hagen tanks also have warning notices stuck to the bottoms.
Also, like Rusty said, tempered glass generally has nicer looking edges. Plate glass is often just ground a bit to make it unlikely to cut you, but it looks rough (look at the edges of a small rectangular tank vs, say, your coffee table).

Beyond that, if you want a real way to tell you'll need a microscope or some kind of expensive and complicated gadgetry. In short: there is no way to tell. Or, rather, no way I've been able to research. Well, I did find this... http://www.astronomy.net/forums/atm/messages/3492.shtml

[muck]

Originally Posted by Rikko

All-glass and Hagen tanks also have warning notices stuck to the bottoms.

Hagen does not use tempered glass on any of their aquariums.

[Canadian Man]

If you look at tempered glass through polarized glasses you will see wavy lines in the glass surface.

Easy.

Any tougher questions?

[Rikko]

I've heard of a few Hagen tanks having tempered bottoms. These were from RC posts of people buying used tanks - they could very well be old, old tanks or maybe a Hagen USA promo at the time (or just a load of crap). Certainly all the "normal" Hagens up to 77 gallons have never been tempered IME.

[whaase]

Originally Posted by Canadian Man

If you look at tempered glass through polarized glasses you will see wavy lines in the glass surface.

Easy.

Any tougher questions?

And I do have some glasses that are polarized! I'll think of a tougher question.

Walter

[danny zubot]

All-glass and Hagen tanks also have warning notices stuck to the bottoms.

Hagen does not use tempered glass on any of their aquariums.

Oceanic uses tempered bottoms on some of their tanks.