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Re: Glasss thickness

> I was thinking of a 48" X 18" X 18". What thickness glass should I specify ?

You can get a nomograph for glass thicknes which allows you to plot the
tanks height verses length and read off the appropriate glass thickness
from several curves shown on the graph. I forget the specific text names
however any book outlining basic aquarium construction should have a
copy of something similar. If not, try the engineering texts at your
library, under materials sciences. Also, check and see if they refernce
a safety factor and a glass type in the nomogram. Not all glass is
created equal and some graphs may present a 'pure' material behavior
while others show the 'applied' values. 

My aquarium is 52"x24"x24 and the nomograph indictaed a glass thickness
just below 1/2". I used 7/16 on all sides and haven't had a problem. The
tank is fully supported on the bottom plate, however by a very beefy
cabinet (laminated 2"x4" for the horizontal members and larger for the
vertical ones). By the way, my glass was salvaged from the front windows
of a convenience store so I don't know how much credance to give those
who recommend only using the high quality German glass. Just something
else to think about.

By the way, you have to remember that these tanks act the same as a very
heavy rigid beam when filled with water. Any flex will cause a crack to
run diagonally across the plate of glass. Chances are, if it happens,
you won't have time to see it. If your constructing it yourself, make
sure the glass is cut well but, more importanatly, have the edges ground
to remove any nicks or chips. These are initiation points for a crack
and they weaken the glass significantly. 

I suggest you go for a very sturdy stand as well as the recommended
glass thickness.

Jason Daniels