Is the glass tempered?

[blakeoe]

My roommate has an old tank that he wants to drill but doesnt know if it is tempered glass or not. We dont know what brand tank it is but he bought it about 10 yrs ago from "pet Superstore" the only markings the tank has is a sticker under the top frame that says EW April 22 1998 Serial # 105430 is their any way to tell if this tank is drillable?

 

[snulma1]

Where does he want to drill it? What size is it? Usually most tanks only use tempered glass for the bottom up to a certain gallon size.

 

[pIankton]

Your best bet is to just assume that all of the side walls are ok to drill and the bottoms are tempered.

Better to be safe than sorry.

 

[blakeoe]

Its a 30 gallon and he would like to drill the bottom but hes not opposed to drilling the back if he has to

 

[kdblove_99]

I would not drill the bottom unless i was 100% sure they are usally tempered. The back more than likely is not tempered

 

[pjf]

Here's a quote from the DIY forum:

<a href=showthread.php?s=&postid=11848633#post11848633 target=_blank>Originally posted</a> by hllywd
Check it yourself to be sure!!! It's very easy (and cheaper than a new tank too...).

I use two polarizing camera filters and like to do this with a clear bright sky as the backdrop. One filter on each side of the glass. Rotate the filters until most of the light is blocked and move both filters simultaneously across the glass while looking at the sky through all three layers. If the glass is tempered you will see light and dark areas or a pattern in the glass. You may sometimes see a similar effect while wearing polarized sunglasses while looking at reflected sunlight on the side or rear windows of a car, never the front windshield since they are not tempered glass but safety glass.
You can try the method I describe on the side window of your car for practice and to see the effect, they are always tempered.

Tim

I've also read that the polarizing filters display a "cross" when viewing tempered glass.

Actually, you can see the little square stress patterns if you put the glass
between crossed polarizers. The polarized light near the horizon, outdoors,
makes the grid-like patterns obvious in auto glass if you are wearing
Polaroid sun glasses.
--
Wright Huntley, Killitalk Forum

 

[Curve]

The tempered glass in my tank has a greenish tint to it and my tank that isn't tempered is clear as can be.