How to determine if glass is tempered?

[RBE17]

I have some tanks that I'd like to drill, but don't know if the bottom is tempered. Is there a way to determine if it is tempered other than going for it and hoping it can be drilled w/o breaking it?

Thanks,


Steve.

 

[NilePufferFanatic]

Huge (+55gal) tanks are typically not tempered. Sometimes there are markings. Idealy you would find where the tank came from and ask them.

 

[RBE17]

These are all 55g+ tanks, but they're all used. I've seen no markings on them to state one way or another. The 55g is a very old tank. I don't know the age of the 75g and 125g. I'll look closer at them to see if I can find a manufacturer.

Thanks,


Steve.

 

[bigspizz]

Look at the bottom pain of glass. If it is tempered, their will be a note or marking somewhere saying such. I would assume all the bottoms are tempered, unless the tanks are old.

 

[sirdavidofdiscus]

Look at the glass through polarized glasses. If there is a rainbow like wave in the glass its tempered. The tank would have to emptied though.

 

[Dan F]

Look at the bottom pain of glass. If it is tempered, their will be a note or marking somewhere saying such. I would assume all the bottoms are tempered, unless the tanks are old.

I agree, according to the owner of the LFS all the major brands of tanks use tempered glass bottoms unless they are specially ordered without. I have an OLD 110 long tank that is made from 1/2" untempered glass on sides and bottom, but it is at least 25 years old.

 

[dchaos52]

My old 55 gallon was tempered, and it had a small sticker that said not to drill

 

[RBE17]

Thanks for the responses. I couldn't find any markings on the tanks. I'll try the trick w/ the polarized glasses.