Tank Stand Support Question

[Zenoah1439]

I'm looking to build a new tank stand for my 40g breeder which would incorporate a sump in the lower section. I'd like to not put a center support in the front of the tank, but have read the "rule of thumb" is to have 1 2x4 brace for ever 2 feet of tank length. I'm wondering if using a 2x6 structure underneath the tank and having no center brace will be enough to support?

I ran the numbers on the 2x4 at a 2ft span with the tank full on top and found that the stress load on the wood is about 171.43 psi. Running the same numbers on the 2x6 support spanning the full 36 inches comes out at 208.26 psi. Both number are FAR less than the yield strength of the wood, so i thought the rule of thumb might be to help with deflection.

Running the numbers for deflection, the 2x4 at a 2ft span will deflect .0045" and a 2x6 at 3ft span will deflect .0077". In either case, having deflection under 7.5 thou seems acceptable. So what drives the "rule of thumb", or do i have inaccurate information? Based on the calculations, it seems like a 2x6 would do just fine supporting a 3ft span with no center brace with the tank full on top? Anyone have experience doing this?

 

[Sasquatch]

Ive got a 100 gal on 2x6 no center, skin the top with 5/8 or 3/4, there's more danger in a sideways collapse than a bow, cross brace the back for safety

 

[dawgwe1]

I just built a stand for my new 40b with a 20g long sump below. I used 2 x 6 for the top support frame, 2 x 4 bottom frame and 2 x 4 legs. No center support. Been up for a month now with no problems. Skinned the front and sides and bottom half of the back.

 

[trido]

I had my 65G (same foot print) on a 2x4 stand with 1/2" top and 1/4" skin on the sides for the last two years without problems. No center brace.

 

[DonW]

No 2x material needed period. The rule of thumb is just something made up in the hobby. No need for a center support on stands 48" and less. Here is a little vid i made of small stand consrtuction that is just fine for a 40. Add glue blocks under the top just like the bottom.


Don

 

[Zenoah1439]

Hey All,

Thanks for the replies. I figured it would be OK, but thought I'd run it by some people who have actually done it. I did some surfing through these forums and found a few posts with wooden gussets at the corners. I liked the idea and will probably integrate it into my design as well for strength. Thanks again for all the posts.

 

[MMERITT28]

Don,

I would be interested in watching that video but when I bring it up it says set to private.

 

[DonW]

The easiest way to think about an AGA type aquarium stand 4ft and under is this. [ ] The brackets represent the needed support with no deflection everything else is for shear load only.

Don

 

[DonW]

Don,

I would be interested in watching that video but when I bring it up it says set to private.

I fixed it. Phone posting I guess doesnt work.

 

[MMERITT28]

Thank you sir.

 

[jrgilles]

Here is a stand I made with no center support. I used gusset plates in the corners to keep it square

https://docs.google.com/open?id=0B9mGKRnnbVEwNmRiYzcxMmMtNGIzNy00ODk0LTg0YzEtNGRjOWQ0NzI1ZGE0

But, you could get away with something much lighter weight for a 40 breeder I would think. You do want to think about something to keep it square though I would think.

 

[trido]

DonW, Nice video! That much like the last stand I built for the 65 Im setting back up in the near future. I agree with you completely the 2x4 construction has become something of a myth as "necessary" in stand construction. I built my last stand for a 175 bowfront with NO 2x material at all and only plywood and 1x and will do it again I'm sure.

IMO, the reason most use 2x4s as a base is lack of building knowledge and tools. Most DIYers don't have pocket screw guides and table saws capable of dado notches (or a large enough table to safely cut a full sheet of plywood) so they use 2x4s as something to attach their skin onto.

With a glass tank, there isn't nearly as much support needed around edges or center as with an acrylic tank.

 

[DonW]

DonW, Nice video! That much like the last stand I built for the 65 Im setting back up in the near future. I agree with you completely the 2x4 construction has become something of a myth as "necessary" in stand construction. I built my last stand for a 175 bowfront with NO 2x material at all and only plywood and 1x and will do it again I'm sure.

IMO, the reason most use 2x4s as a base is lack of building knowledge and tools. Most DIYers don't have pocket screw guides and table saws capable of dado notches (or a large enough table to safely cut a full sheet of plywood) so they use 2x4s as something to attach their skin onto.

With a glass tank, there isn't nearly as much support needed around edges or center as with an acrylic tank.

I say use what ever you have or are capable of using, just dont get into the whole engineering bit. You can support a 4' aga type tank on four plain old every day 2x4's if you could keep it from falling over. Picture 4 2x4's cemented into the ground with the tank corners resting on them. All the rest is shear load. People get to wrapped up in vertical load and molest a forest for wood that is not needed. Pains of glass are not going to flex vertically they will only twist (shear load). Same theory as an egg standing on end.

Don