how to tell if glass is tempered

[CorbetJackson50]

I have a frag tank 48" x 24" x 12" and i am not sure if it is tempered or not, i dont want to drill it and break it. It is 1/4" glass

[ang_99]

I would say throw a brick at it, if it doesn't shatter.. its tempered.

[CorbetJackson50]

yeah sounds like a great idea

[Barney_Googles]

any idea on the manufacturer???
sometimes you can get a clue from the bottom or the frame of the tank?

[Roy G. Biv]

Put on polarized sunglasses. If you look at a cars rear window and you see a checkerboard, its polorized. Look at the tank, if you see a similar checkerboard then its tempered.

[chucksta1]

That "sunglasses" is so cool! Now I can throw out my "test hammer".... But tell me, does it only work in sunlight??

[CorbetJackson50]

i only wear polarized sunglasses and i know exactlly what you are talking about. thanks. The tank is made by inknown manufactuer maybe a glass cages tank, it is rimless

[da1jewfish]

Originally posted by Pmolan
Put on polarized sunglasses. If you look at a cars rear window and you see a checkerboard, its polorized. Look at the tank, if you see a similar checkerboard then its tempered.

I too know what your talking about, but if this is the case shouldn't all car windows be tempered? because with me I only see the checkerboard on occasion. Also, why is it only the rear window? I'm just trying to figure of this method will work all the time when looking at a tempered tank?

[DiverD]

Tom dosent like do tempered as far asa I know. He can't cut it down at glass cages....

[returnofsid]

If you do a google search on the sunglass trick, you'll find that it's somewhat successful. It kind of depends on the manufacturer of the glass. Most tanks are only tempered on the bottom, while the sides are not. However, that's "most" not all.

[DiverD]

I have dealt with Tom at GC extensively. I am not at liberty to discuss in the open forum, but if you PM me I can give info for and some against. I own and maintain several of his tanks btw.

[chucksta1]

"Also, why is it only the rear window? I'm just trying to figure of this method will work all the time when looking at a tempered tank?"

There are two types of automotive glass one is a laminate,, two pieces of glass with a plastic layer in between. this glass will crack, bit tends to stay in one piece. Then there's "tempered" glass. this is the stuff that explodes into little honeycomb like pieces instead of sharp shards like window glass.

I don't know for sure why laminate is in the front.. maybe from the days before seatbelts to keep you in the car?

[sundancer]

I think the front glass is laminate because when people get into a crash their heads would smash through the tempered glass. On the whiplash when their heads get jerked back into the car their throats would get slashed by the edges left by the tempered glass So I was told by a fellow who knew everything.

[Rustylugnuts]

Put on polarized sunglasses. If you look at a cars rear window and you see a checkerboard, its polorized. Look at the tank, if you see a similar checkerboard then its tempered.

+1

It would also help to place a polarized filter (sunglass lens) behind the glass as well. Stress lines are far more noticeable that way.

[limitdown]

Put on polarized sunglasses and light the glass from behind using an LCD monitor set to white, the checkerboard patterns are more visible this way