Thinking about building my own stand and tank - The Planted Tank Forum
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post #1 of 16 (permalink) Old 02-17-2009, 08:21 PM Thread Starter
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Thinking about building my own stand and tank

Hi all.
I have made a sketch of what i want and i just wanted to run it by a few ppl and mabe get some feed-back. I want the stand to be tall so when i am standing infront of the tank the middle part is at eye level (i have already bought steps so i can work with the tank). The tank will be made of 12 mm (12 millimeter = 0.472 440 944 88 inch) glass, the stand will be made of 2x4“s with the bottom, top, sides and back out of 15 mm (15 millimeter = 0.590 551 181 1 inch) wood plates. Like so
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This is what i would like butt i dont know anything about building either of these things. I am concerned about the height of the stand (will it bend over or not?) and wether i really need braces or not on the tank? Also how much should i shave of the glass dimensions for the silicon?
Thank you for any and all advice you can give me.

David
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post #2 of 16 (permalink) Old 02-17-2009, 09:06 PM
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It will probably be over built if anything. You probably don't need the horizontal braces across the back and sides. Otherwise, it looks to be a very good design. No need to worry about it bending. Remember, 2x4's hold up houses!
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post #3 of 16 (permalink) Old 02-17-2009, 10:37 PM
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the stand seems kind of tall
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post #4 of 16 (permalink) Old 02-18-2009, 07:22 AM Thread Starter
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Ok over building sounds good to me, better then under. It is quite tall, but i want to try it out and see how i like it. I can allways make a smaller stand if this one dosent work for me.
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post #5 of 16 (permalink) Old 02-18-2009, 07:34 AM
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U dont need the horisontal studs (hope thats the right word in english) plywood on the sides and back will bee more than enough to prowide stability!
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post #6 of 16 (permalink) Old 02-18-2009, 03:09 PM
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I only see one issue that i would question. It's the front bottom portion of your stand. I noticed that the center vertical beam runs straight to the floor and you have your front bottom horizontal beam cut into two pieces and attached the that vertical middle beam. I persoanally would make the horizontal bottom beam one full beam, and join the vertical beam ON TOP of the horizontal piece this way the weight that is placed on that front vertical beam is dispersed along the length of the horizontal piece and not directly to the floor with a 2X4 foot print

Oh..i just noticed...'d change it on the rear portion of the stand too
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post #7 of 16 (permalink) Old 02-18-2009, 05:23 PM
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I agree with timelessr1 about the horizontal 2 x 4's. I would also be sure to have a plywood panel covering the back to make it more resistant to "racking".

The tank sketch shows the top front and back strips that brace the glass so it doesn't bulge out being cut shorter than the front and back glass panels. It will be much, much better to have them siliconed to the end glass panels, too, so the seam along the long edge of those strips isn't being relied on to stop them from bending down. (I think that is understandable?)

Hoppy
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post #8 of 16 (permalink) Old 02-18-2009, 07:14 PM Thread Starter
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Ok i changed the structure a little, from what i understanded from your suggestions. Think i got it right, although i did cut a little in the bottom beam, would it be better if the vertical bottom beam would be completely hole?
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Also how much should i shave of the glass to make room for the silicon?
There will be a solid botom and top butt the back and front will be to pieces of 15mm a little over half an in. wooden boards, simillar to plywood i think
(in my language= krossvišur ).
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post #9 of 16 (permalink) Old 02-18-2009, 07:54 PM
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Originally Posted by davidoe View Post
Ok i changed the structure a little, from what i understanded from your suggestions. Think i got it right, although i did cut a little in the bottom beam, would it be better if the vertical bottom beam would be completely hole?
Attachment 12086
Also how much should i shave of the glass to make room for the silicon?
There will be a solid botom and top butt the back and front will be to pieces of 15mm a little over half an in. wooden boards, simillar to plywood i think
(in my language= krossvišur ).
Attachment 12087 Attachment 12088
The bottom horizontal piece doesnt have to be whole, but why not make it whole? I would turn the horizontal bottom beam so that its not sitting upward, basically lay the beam down so you have the 3 1/2 inches width touching the floor, and then justt put the vertical beam right on top of the horizontal piece. No real need to notch out the botom piece. you can still use the "L" brackets if youd like for support so that the vertical peice doesnt move to the side at all.
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post #10 of 16 (permalink) Old 02-19-2009, 03:06 PM
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The first thing that comes to my mind here is stability. As you raise the tank higher you are also raising the center of gravity. As the center of gravity gets higher it takes less force for it to tip over. This only gets amplified by the fact that most of the weight is located at the top.

Things that would help prevent this? A level floor is very critical. If you live in an area that gets earthquakes I would attach it to wall or floor. You could also put more weight in the base of the stand.

It would suck to be scrubbing algae on the glass and have the whole tank and stand tip over.

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post #11 of 16 (permalink) Old 02-19-2009, 04:05 PM Thread Starter
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Good point. True, that would wery much suck.
Attaching it to the wall will be no problem, i will do that.
Dont know about attaching it to the floor but i will keep that in mind.
I just bought a book online about building this and that for pets, includding tank stands, mabe it has some other pointers aswell. But it wount arrive untill next month, wich is ok, im in no hurry. This is my first attempt and i want it to be succesfull.
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post #12 of 16 (permalink) Old 02-19-2009, 05:26 PM
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I think you will be very successful making the stand. Now, the tank is another question. I admire your willingness to tackle such a challenge.

About the stability of high stands like that: the weight of all of that water on top makes it much more resistant to tipping over than you might think. In order to tip over, without destroying the stand, the stand has to pivot about the front or back bottom edge, requiring the tank to lift up a bit. That means any tipping is also lifting the whole weight of all of that water. Granted that you have leverage with the high tank, I still don't believe you can exert enough force sideways to make the tank lift. An earthquake is another matter. The tank could just slide off the top of the stand if the earthquake were severe enough. But, I suspect you would have other things on your mind in that case.

Water heaters are required to be strapped to the wall so they don't topple in an earthquake, but water heaters have 30 gallons or so of water in them, not 100 gallons, and they are much less stable, with a very small "footprint". If you strap the stand to the wall, the tank just slides off. If you strap the tank to the wall, the tank very likely just shatters. I suggest instead, you keep a close eye on all the dogs and cats in the neighborhood, and when they all get antsy, a good sign that an earthquake is about to hit, just quickly drain the tank and move it to the floor. QUICKLY!!!

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post #13 of 16 (permalink) Old 02-20-2009, 04:06 PM
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Hoppy I mean this in the nicest way possible, but you are way off.

You are right about the lever. The greater the ratio height compared to the width of the object, H:W, the less force it takes to tip over.

The fact that the majority of the mass is located and the top only amplifies this. With the center of mass is raised above the geometric center of gravity an overturning force is very easy to create from the mass of the water alone. When a force is applied to the tank, scrubbing the glass...sloshing water, it creates an eccentricity between the center of mass and center of gravity and moves the center of mass away from the center of gravity. This creates an overturn moment about the center of gravity and adds to the force already being applied that caused the eccentricity in the first place. The further the center of mass is from the center of gravity the great the overturning moment is.

This is an inherent problem with all stands. Which is why almost all commercial stands are the height they are. They are trying to keep the center of mass as close to the center of gravity as possible. In this case we have put a great distance between the two centers. Which will greatly reduce the force required for it to tip over.

But what do I know. I am only a licensed structural engineer.

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post #14 of 16 (permalink) Old 02-20-2009, 06:58 PM Thread Starter
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Thanks for the comments.
I am wondering though if i should take a 1mm or 2mm of the lenght of the side glass panels to make room for the silicon?
1 millimeter = 0.039 370 078 74 inch
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post #15 of 16 (permalink) Old 02-20-2009, 07:59 PM
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Hoppy I mean this in the nicest way possible, but you are way off.

You are right about the lever. The greater the ratio height compared to the width of the object, H:W, the less force it takes to tip over.

The fact that the majority of the mass is located and the top only amplifies this. With the center of mass is raised above the geometric center of gravity an overturning force is very easy to create from the mass of the water alone. When a force is applied to the tank, scrubbing the glass...sloshing water, it creates an eccentricity between the center of mass and center of gravity and moves the center of mass away from the center of gravity. This creates an overturn moment about the center of gravity and adds to the force already being applied that caused the eccentricity in the first place. The further the center of mass is from the center of gravity the great the overturning moment is.

This is an inherent problem with all stands. Which is why almost all commercial stands are the height they are. They are trying to keep the center of mass as close to the center of gravity as possible. In this case we have put a great distance between the two centers. Which will greatly reduce the force required for it to tip over.

But what do I know. I am only a licensed structural engineer.
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