tempered glass how to tell

[cope]

is there a way to tell tempered glass ... you can not drill tempered glass (correct?)    is it a different color ... how would you know?

[Delock]

Re: tempered glass how to tell

It would normally be stamped or label on the bottom of the tank

can you take a picture?

[edmlfc]

Re: tempered glass how to tell

It would normally be stamped or label on the bottom of the tank

can you take a picture?

The bottom of my tanks have a sticker that say tempered glass do not drill. But if it's a used tank the previous owner may have taken the sticker off. Don't know if there is any way to tell if that's the case.

[cope]

Re: tempered glass how to tell

would tempered glass shatter or crack..... the bottom of this tank has a crack in it... would that give any indication?  I am going to pick it up later...... I will use it for a  paludarium  so the crack does not bother me at this point... But I wanted to drill the bottom to run some overflow pipes..... I have no clue as to what I am doing... but I have a great idea... if it works great if not.. then Oh well.....

[Delock]

Re: tempered glass how to tell

Cope take a picture and post it online. Do you know the tank brand name?

[cope]

Re: tempered glass how to tell

I will .... I have to go get it... check this thread later.. thanks..

[Spot86t]

Re: tempered glass how to tell

Taken from http://www.atmsite.org/contrib/Pouls.../atmsect3.html

How do you tell if it is tempered? Look at it through crossed polarizers - tempered glass usually shows a lot of strain bifringence. Get some polaroid material (cheap plastic clip-on shades will work) and view through the glass with one sheet on each side rotated 90 degrees to each other. For instance, clip on one pair to your glasses, hold the other polarizer in front of your light source and rotate it until you get maximum extinction. Now insert the glass in question between the polaroids. Tempered glass will exhibit distinct patterns of dark and light bands or other shapes. You might even get groovy colors. If you can see through the glass edge-on, then it will show a dramatic pattern of colored bands parallel to the faces. If you see no patterns, and light is evenly extinguished as you look through it, then it is not tempered and is pretty well annealed.

Finally, you can examine the glass closely for any brand name etched into it. Examine the edge for any sign of fire polishing. Examine the surface for little dimples where tongs may have indented the glass. Any of these indicate tempering, and you should not try to cut or grind this glass, or you will have a terrible mess.

[wesleydnunder]

Re: tempered glass how to tell

If it's cracked, it's probably not tempered. The interior of tempered glass is under pressure. Any crack or deep enough scratch that breaks the surface layer causes the sheet to virtually explode into very small pieces.

Mark