Tempered Glass, How to tell?

[beefcake78]

I was given a 30g cube with no brand info. Is there any way to tell the brand of tank or if the bottom or sides are tempered? I would like to drill it.


thanks

[stugray]

Yeah....try to drill a hole in it, youll know right away!


Just kidding, I have heard that you can tell if you have a polarized light filter. Any high school teacher has some, or you can use polarized sunglasses. Compare the look between two pieces of glass. One that you know is tempered ( usually commercial windows ) and something that is not ( older single pane windows ).

The differences between patterns are obvious.

Stu

[jasonkola]

there is usually two ways to to tell if glass is tempered. usually the company that tempers the glass usually will stamp a mark in the corner of the glass that states it is tempered. the other way is a little more tricky. I will try my best to explain it as best I can. you will need to lay the glass down in a manner in wich you can look down the surface of the glass almost parallell to the surface. basicely you will be looking at the edge of the glass but down the surface of it if that makes any sense. you will also have to make sure there is good light reflecting of the surface. pointing the glass tword a light sorce will help. when you look down the surface tempered glass will be slightly wavey (not completely flat). normal annealed glass is vary flat. tempered glass warps slightly when it is tempered.

[jmkarcz]

Or, you could take the demensions and check as many comon tank makers in the 30 gallon range until you get lucky....

Good luck. The Absolute worst that could happen, is that you limit your hole or holes to 1 panel, drill a hole... if your successful yeah! If not, you take a trip to a local glass company, and buy a new plate glass side, scrape and clean silicone, drill, and silicone in to the tank...

I might remind you to wear eye protection. I also don't put any stock into the POLARIZED theory. Like JFK, I have my doubts. I picked up a 55 this past summer, free. Thought I would turn it into a water RO container for top off's and mixing salt. I was wearing my polarized sunglassed (Oakly). The tank was outside in the bright sun. I walked around it. Carried it. Turned it to get it in the car. Carried it into the house... never saw anything... The weird part is that I can see what everyone is talking about in my car windows, and office windows... but not the tank.

We are still pulling safty glass out of the rafters in the basement. I ended up repairing it and using it for a filter.


Jason

[240-Reefer]

Its much simpler than all that
A standard glass cutter wont cut tempered glass
Take a glass cutter and try cutting a little line where you want to drill. If its tempered; nothing, if it isn't youll hear crackling like its cutting. Drill away.

[javatech]

<a href=showthread.php?s=&postid=6705851#post6705851 target=_blank>Originally posted</a> by jmkarcz
I also don't put any stock into the POLARIZED theory.

Jason
You need two to make it work

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.

[cmacld]

<a href=showthread.php?s=&postid=6705852#post6705852 target=_blank>Originally posted</a> by 240-Reefer
Its much simpler than all that
A standard glass cutter wont cut tempered glass
Take a glass cutter and try cutting a little line where you want to drill. If its tempered; nothing, if it isn't youll hear crackling like its cutting. Drill away.

Heres your answer right here! The easiest and fastest way to tell.

[javatech]

If you try "cutting a little line" on tempered glass it will break in to a lot of small bit's:eek2:
But then you will know that it Was tempered Glass:eek1: :mad2:

[240-Reefer]

<a href=showthread.php?s=&postid=6708349#post6708349 target=_blank>Originally posted</a> by javatech
If you try "cutting a little line" on tempered glass it will break in to a lot of small bit's:eek2:
But then you will know that it Was tempered Glass:eek1: :mad2:
No, the Glass place that cut mine tested my 120 like that. with tempered glass the wheel will simply slide across the glass leaving no cut or weakness. He did say dont do it near an edge.

[RichConley]

If its a 30 cube, its probably oceanic, and is tempered on the bottom, but not hte sides.