RE: [GSAS-Member] rocks in a 90 gallon

["Hess, Clay A" <clay.a.hess@boeing.com>]

Sooooooooo, without doing all the math and research to see what glass
can handle and having put some crazy huge rocks in tanks of glass with
no visible side effects.....I will give my best guess if you like.  If
you do not "point load" the glass you will be fine with whatever rock
you place in the tank.  Soooooo, what does "point load" mean?  It means
do not place all the weight on one tiny spot on the tank floor.  If your
rock has sand underneath it to help dissipate the load across the glass
tank floor you will be fine.  If you let the rock sink through the sand
such that all the weight could potentially rest on one point on the
glass floor you could be in for some issues.  
I can give you an example of what happens with point loads in airplanes.
If you get on an airplane in tennis shoes the aircraft floor will
support the load easily, as it is spread out over the entire shoe base,
and you will make it to your seat.  If you get on an airplane in stileto
heels and try to accomplish the same thing, you will find the heels
punching holes in the floor and it will be very difficult to make it to
your seat.  
Sooooo, it is all about the number of pounds per square inch you are
placing on your floor, be it glass or foam core aluminum panels.  I am
sure if you wish to do a little surfing online you can find the pounds
per square inch your glass is designed to handle.  Doing some quick
estimates of your tank size....and I could be off a bit.  If I assume
your tank dimensions to be about 2'x4' on the base and assuming the
weight of water and rock to be about 10 lbs/gallon of tank space.  You
come to 900 lbs/1152 square inches or .781 lbs/square inch.  Doing a
little surfing myself, here are some average glass strength values
Annealed Glass 6,000 psi, Tempered Glass  24,000 psi.  These values are
based on a Typical Breaking Stress (large light 60 sec. load).  This is
all fine and good, but, your load from rocks will not be a typical 60
sec. load.  Even so, you can see glass can take a heck of a load
compared to what you are currently putting on your tank.  
Soooo, all that said, be careful.  If you are truly working with
tempered glass you need to make sure you do not scratch it near where
your higher loads are placed on the bottom.  Simple scratches in
tempered glass can be a invitation to disaster as the glass will shatter
easily once the surface has been damaged. This is why you cannot cut
tempered glass by etching it and snapping it.
Wanna learn more about glass than you could ever imagine.....check this
out.....http://www.glassonweb.com/glassmanual/topics/index/tempered.htm

Now, your house floors.....there is another load issue.....but, that is
another discussion.  One quick suggestion here though....do not build
your aquarium stands on stiletto heels. 

Clay                  
 

          
 

 


-----Original Message-----
From: Susan Welenofsky [mailto:welenofsky@comcast.net] 
Sent: Sunday, February 27, 2005 5:21 PM
To: 'Greater Seattle Aquarium Society member chat'
Subject: RE: [GSAS-Member] rocks in a 90 gallon


The bottom is probably tempered glass, so it will be extra strong. I
would contact All Glass and ask them to be sure. I would like to see a
picture of your wall and tank!

Susan

-----Original Message-----
From: gsas-member-bounces@thekrib.com
[mailto:gsas-member-bounces@thekrib.com] On Behalf Of Trish
Sent: Sunday, February 27, 2005 5:15 PM
To: Fish List
Subject: [GSAS-Member] rocks in a 90 gallon

I need a question answered. And hoping someone here
can help me.

I need to know how much rock can a 90 gallon hold. It
is an All Glass Aquarium, is on a wood stand, with
only the plastic bar which comes across the middle on
the bottom. I have no plywood underneath. Tank is
filled and has been running now for 5 years, so
putting one underneath is not an option.

Thanks in advance!

Trish

BY the way my rock wall is finished and is going in
this tank, but have exsiting rock in here
already.....so need to know how much wieght it can
support. I let it cure now for 4 days. Outside....so
no oder left.


                
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