How to tell if glass is tempered.

[Tigre9]

I found the web address listed below very helpfull when I was going to drill my 55gal glass tank. I could not tell if the sides or bottom were tempered.

Check out this link, pictures were included with how to use any computer LCD screen to check the glass before you drill.

Hope someone else is able to save their tank!

http://www.salt-city.org/showthread.php?t=9542

 

[kynsee]

Usually if a glass is tempered, it'll have a sticker at the bottom of the tank saying, "Do Not Drill." Check your tank for the sticker. Did you buy the tank new or used?

 

[hllywd]

A sticker is NOT a good way to tell. What if it fell off, washed off, or was removed for some reason? The only foolproof way to know is to physically check it.
I normally use two polarized filters to do the same thing as the laptop test and it works great. You can always practice the method by checking the side window of a car (not the front windshield), side glass is always tempered.
Tim

 

[jayray]

+1
Cool method to test! Gonna try it out on a 55.. Might be my new sump!
J

I found the web address listed below very helpfull when I was going to drill my 55gal glass tank. I could not tell if the sides or bottom were tempered.

Check out this link, pictures were included with how to use any computer LCD screen to check the glass before you drill.

Hope someone else is able to save their tank!

http://www.salt-city.org/showthread.php?t=9542

 

[Tigre9]

In reply to Kynsee about the stickers.

Actually that was the problem, there were no stickers on the sides. The bottom had one showing tempered however no manufacture name listed. This ended up being my solution... and it worked great.

 

[FranktheTankTx]

Drill it - most sure fire way to determine if it's tempered.

 

[Tigre9]

I like this method better, I do not have to throw money away and destroy anything just to find out if a tank can be drilled! Polorized is the way to go...

 

[TAB]

polorized is not full proof. the only full proof way I know of is to look for any deep scratchs, if it has them and its intact, its not tempered.

 

[hllywd]

polorized is not full proof. the only full proof way I know of is to look for any deep scratchs, if it has them and its intact, its not tempered.

The polarized filter method is much more reliable. How many times have you seen a side, or rear window of a car with a scratch? Those windows are always tempered and get scrtched all the time without breaking. In fact routinely at work in extrication training people try to break side windows on vehicles with a pickhead axe, frequently they are surprised when the axe bounces back at them leaving a nice divot in the glass which is otherwise intact. I've seen it when several students have multiple swings at the same car window, leaving a mark with every swing.

I've never tried filters on a known piece of tempered glass where that method didn't work and have yet to drill a tempered tank after checking it first with the polarized filters.

Tim

 

[uncleof6]

The only foolproof method of determining whether or not glass is tempered: (there are other models available from different manufacturers)

http://www.technologylk.com/crl-tempered-and-strengthened-glass-detector-lk-SG2700.htm?src=froogle

Also, be aware, that the vast majority of 55 gallon tanks ARE tempered. Sides and bottoms. Notoriously so.

Jim

 

[hllywd]

The only foolproof method of determining whether or not glass is tempered: (there are other models available from different manufacturers)

http://www.technologylk.com/crl-tempered-and-strengthened-glass-detector-lk-SG2700.htm?src=froogle

Also, be aware, that the vast majority of 55 gallon tanks ARE tempered. Sides and bottoms. Notoriously so.

Jim

Hey Jim,

Isn't that using reflected polarized light to accomplish the same thing as the polarized filters? I looked briefly to see if I could find more info and didn't. From the description it sounds like a very similar process to seeing the stress lines through polarized glasses with the sun reflecting of a car window... only in a handheld tool.

Tim

 

[uncleof6]

And a rather pricey one at that. But not everyones eyes "see" the same, just as with color (the perception varies,) also the reflective intensity varies, so for 100% reliability, the tool is the way to go. I am not suggesting, that anyone that wants to know if the glass is tempered, go buy the tool--any glass shop worth patronizing will have such a tool. (as well as a tin side detector ) I am suggesting there are some variables with "homegrown" remedies, that could leave your tank in a thousand pebble sized pieces. I have heard both positive and negative stories on polarized filters/glasses, and I never said this, but I personally detonated a tank that did not "show". Ok, so I am blind...

Jim

 

[hllywd]

Good reason to always wear your safety glasses!:dance:

 

[uncleof6]

Good reason to always wear your safety glasses!:dance:

by varilux..... :bigeyes:

 

[pepsiDX20]

My 55's front/back/sides were not tempered. Bottom WAS tempered. I used the lcd/polorized sunglasses technique to check.

 

[fd678]

good reason to always wear your safety glasses!:dance:

+1

 

[firebirdude]

I've tried the LCD screen method and couldnt see jack either way.

 

[hllywd]

Maybe it's not tempered then... did you try it on a known piece of tempered glass to actually learn how to do it?

 

[TAB]

car windows are not the same as standard tempered glass... as to the pick axe bouncing off, a spring loaded center punch will shatter any side window of a car.

 

[hllywd]

Tempered is a generic term and easily identified using specific equipment, and I submit other methods. The pick end of a pick head axe is the tool of choice in the absense of an automatic center punch during extrication, and forcible entry operations. The center punch would have an identical effect on a tempered tank as a vehicle window, Similarly tank glass may be scratched without immediate catastrophic results.

Tim