So there would be no troubles making a plywood tank using glass from say a 20 gallon tank to build say a 200 gallon tank given a person doesn't exceed the smaller tank's original depth when they placed the glass, correct?
Hydrostatic Pressure Calculation (Pressure on tank walls)
- Thread starter nolapete
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In theory, yes. If you have enough cross supports on the top, you might be able to get away with it.
This thread was mainly to clear up the pressure mathematics. If your glass side is to long, there will be to much pounds of force on the glass and will cause it to bow outward to far and break.
I have never built a tank and never read up on it to much. Here is a calculator I found and edited for easier viewing and usability. Its not mine. It was originally found HERE
Edited Version HERE
In that calculator, a tank 16" deep and 24" long with a 3.8 safty factor would need .23" glass thickness. Those dimensions come from a 20 gallon tank. Using the same depth but instead 72" long would require .27" glass.
So both you could use 1/4" glass. So if you did 72x72x16 = 359 Gallon aquarium, you could use 1/4" glass. Length doesn't make it change much.
Now if you took the same length but changed it to 24" high. (72"L x 24"H) Only another 8" difference. The calc says you need 1/2" glass. Another 1/4" thicker for 8" deeper tank vs, .04" difference for 48" difference in length
Notice the trend? Height is more important, but for VERY long tanks, you will want to use thicker glass.
This thread was mainly to clear up the pressure mathematics. If your glass side is to long, there will be to much pounds of force on the glass and will cause it to bow outward to far and break.
I have never built a tank and never read up on it to much. Here is a calculator I found and edited for easier viewing and usability. Its not mine. It was originally found HERE
Edited Version HERE
In that calculator, a tank 16" deep and 24" long with a 3.8 safty factor would need .23" glass thickness. Those dimensions come from a 20 gallon tank. Using the same depth but instead 72" long would require .27" glass.
So both you could use 1/4" glass. So if you did 72x72x16 = 359 Gallon aquarium, you could use 1/4" glass. Length doesn't make it change much.
Now if you took the same length but changed it to 24" high. (72"L x 24"H) Only another 8" difference. The calc says you need 1/2" glass. Another 1/4" thicker for 8" deeper tank vs, .04" difference for 48" difference in length
Notice the trend? Height is more important, but for VERY long tanks, you will want to use thicker glass.
nickelnutz;2962955; said:
IMHO, you'd be pushing it. Not because of the pressure, but because any flex on glass that thin and it's history.
Lets just say that its a new peice of glass and its being supported on on all 4 edges by a piece of plywood that has a rectangle cut out for the glass. It would hold up just fine.
Now I didn't think about if nickelnuts was talking about removing the piece of glass from the 20 gallon or using the same thickness and height, just different length.
Either case, it would hold up as long as you support it correctly. using the length of glass the a 20 gallon uses, you will not need to support it in the middle, no matter if it was a million gallons. If it was any longer though, probably 3' or longer, I would start adding supports.
You could have a 1000 Gallon aquarium, lets say its only 20" deep and the ends of the tank are 48" long. You could use 1/4" glass on this 1000 gallon aquarium. Now I always say add a cneter support since this will help with bowing. The front and back, which will be MUCH MUCH longer, I could figure it out, would have to be thicker because of the span.
If you're talking about a 20 high which is 17" (give or take) tall and 24" long and 13" wide, to get 200 gallons at the same height you'd have a tank 130" long x 24" x 17". You'd have to brace it. Plywood will flex enough under pressure to torque a piece of glass enough to break it. Not a chance I'd want to take.
Right, thats why I was saying, anything longer than 3 ft I would start adding braces, but the thickness would work. If you used that specific piece of glass, 24"L x 16" H on the end of a 200 gallon tank, you would not need to brace. You can use the same thickness on the front and back but like you said, brace it.
You know I havn't seen this spoken about much so I am glad you made this thread.
You know I havn't seen this spoken about much so I am glad you made this thread.
Just to clarify for you, if I were to take the front glass from a standard 20g (24"x16"x3/16") and use it as the viewing window of a say 200g plywood tank (regardless of dimension). It should hold provided that either the tank was only 16" deep or that the glass was at the top of the tank's side, right?
The dimensions are the most important with a question such as this. The amount of gallons doesn't mean much. Like I said earlier, you could have a 1000 gallon aquarium and use 1/4" glass @ 16" deep.
You could use 3/16" but the safty factor will drop.
Correct. If the tank (regaurdless of the volume), was only 16" deep, you can use it as the side of the tank as long as its supported if it needs to be. 24" long will not need to be supported usually. If you use as a viewing window adhered to the plywood, then you would need to make sure the plywood is strong enough not to bow. Since plywood is more flexable, you may need to add supports. Especially if its a long span.
The glass doesn't need to be at the top though. If this 200 gallon aquarium is only 16" deep, don't worry about trying to move it to the top. Unless ofcourse, the tank is deeper than that, say 24 or 48" deep, then you will want to glass more toward the top of the tank and no more then 16-20" down.
