[Dan-Boy]

Well heres an idea for all those who build their own tanks, and those who are having to fit tanks on existing stands. This is called a Torsion Box and should be built to the same size as the base of your tank. Once built correctly this design allows even load distribution from your fish tank to its stand..even if the stand is smaller (to a certain extent) than the base of the tank itself.



Apologies for the rubbish image quality, anyone wanting the actual file can email me (Dragonfly_507@hotmail.com). The design is used frequently by Carpenters as a moveable workbench sat on two saw horses. I myself was a carpenter for 5 years until i decided to become a Structural Engineer hence my knowledge.

Hope this Helps someone (share the wealth and all that :D )

Dan

[LuvMuhFred]

Nice one :)

I have no idea on carpentry so I cant judge if it works. Have you used it? if so with what results?
Im interested as I am having probs with getting my new tank due to finance so I may have to get it without a stand :(
My x hubby could make this for me.....but Id like to know results before I ask him a favor yanno.

[Dan-Boy]

yeah it works fine...as you can tell the emphasis is on structural stability rather than how nice it looks. But then there is always the possibility of adding some decorative moldings etc to it.. just make sure the material your husband makes it from has 2 nice straight /parallel edges ..then if all the edges are aligned flush with one another...the whole thing will be 'dead flat'

In essence, its the grid structure that matters and the thickness of the finished article (hopefully 4") , not the thickness of the material itself (i.e 1/2" ply)

hope this helps/makes sense..but don't hesistate to ask! :D

Dan

[LuvMuhFred]

sorry took me so long :(

I dont mind bout adding decorative moldings, to be honest im into modern/contempory so a nice clean sharp lines wil do me fine :)

so far my tank is still on hold UGH
Do you mind if I save that design to pass onto my x incase we need it?
he is in the process of making me custom made tank covers in acrylic at the moment but this will be his next project if i cant get a stand.

[Dan-Boy]

Please be my guest!, or you can email me and i'll send you a copy of the the actual picture..the imageshack one is abit rough!

Dan

[tinkerbell]

great tip Danny-Boy :D

[Bak2it]

Dan-Boy, you forgot to add one little detail in your design... The bottom skin. Without a skin on both sides, a torsion box is still strong but it looses a good percentage of it's structural stability and load transfer ability.

Without a doubt, torsion box construction is a great way to make a strong light weight surfaces. The wings of an airplane, hollow core doors, the floors in your home, engineered beams and skis and all examples of products that are constructed using this technology.

For anyone that's considering building a torsion box to set an aquarium on, there is one point that's very important. The torsion box MUST be constructed on a flat surface, and the final assembly MUST be flat. If there is ANY warp in the torsion box it will cause your aquarium to leak or even break.

If you want to put your aquarium on a tank base that's only a couple of inches smaller than the aquarium, you can just use a piece of 1" thick plywood. It will support the load with no problems and cutting one piece of plywood is much easier than building a torsion box.

Another thing to remember... The base you put the aquarium on must be strong enough to support the load of the larger tank. Aquarium bases are designed and built to hold a specific load. There is a built-in safety factor, but don't expect an aquarium stand that was built to hold a 29 gallon tank to support the additional two-hundred plus pound load of a 55 gallon tank, even if you use a torsion box.

By the way Dan-Boy, I'm a mechanical engineer, with over thirty years of experience.

[Dan-Boy]

Congratulations Bak2it on over 30 years long service..nothing left to chance there!

I personally do not agree with your point that the torsion box MUST be constructed on a flat surface..infact i don't think it matters what surface its constructed on as long as each piece is straight edged, of similiar width..and that all the straight edges are aligned at the top flush with one another.. I also don't agree with the the need for a bottom piece of plywood.. the forces involved in the support of a fish tank are primarily gravity loads, not lateral loads. The vertical load capacity of the torsion box relies on the tight fitting of the 'Honey comb' structure. The reason is that the tension/compression due to gravity should be soaked up by the internal members not the outer skin.

One piece of ply on the top edge will be enough to supply lateral bracing. tThe tension capacity of the upper skin in the vertical direction is considered minimal, and the compression capacity of the lower skin is negliable. The open bottom edge will also allow the capacity to afix a bracket attaching the torsion box to its new stand.

other than that i agree with you entirely about the use on 1" ply bases and factors of safety.

I do Love abit of professional banter (altho perhaps here is not the place)

Dan

[Bak2it]

I have to agree that an open goldfish forum isn't the ideal place to iron this one out... Especially since you're approaching it from a theoretical standpoint, and I'm looking at it from a manufacturing point of view. Let's leave this one alone, until we have to opportunity to sit down with a few beers.

Rick

[Dan-Boy]

i like you already bud! :D

Dan