Planning to build this

[maxumis]

After much consideration, I have decided that I will build a plywood tank this summer(Southern Hemisphere Summer). The outer dimensions will be 2440mmL x 650mmW x 1065mmH. I have finally sourced all the components needed for the project.
I had planned on building one before, but I wasn’t able to source Pottable water safe epoxy. I have since found a supplier of an “acrylic” 2 part epoxy. SAFE FOR POTTABLE WATER. Whoo hoo! So come middle November, I’m off to the races!
I plan on getting enough epoxy to do the following; 1 layer whole tank. 1 fiberglass layer all conners and seems. 1 layer whole tank. 1 fiberglass layer whole tank. 1 layer whole tank. 1 fiberglass layer whole tank. 1 layer whole tank. 1 fiberglass layer corners and seems. 2 + layers whole tank. That should be plenty strong.
Glass will be 10mm with 2136mm x 550mm exposed glass(45mm minimum rebate around edges.)
I will use 18mm plywood. And braces on the tank will be 38mm x 114mm (2"x4") pine wood. As for the stand: I originally planned on doing a classic beam – and – ply stand. I now plan on doing the stand completely out of 3/4” plywood, just to prove a point.
I’ll post my findings when the tank is full and is standing on its plywood only stand. I should mention that the current stand design will consume 3 whole sheets!

The reason for the lifted window, is to gain volume, without having to purchase stupidly expensive glass. Any thing over 10mm gets way beyond my budget reach.

Anyway. Please have a look, and give some feedback. What would you worry about with this design?

 

[Dr Joe]

Looks and sounds well thought out.

The stands sounds interesting...do you trust your design enough to fill the tank inside?

J/k.

These are the times I wish I spoke metric, I have to keep refering to my conversion charts. But I have always resisted change

Dr Joe

.

 

[maxumis]

Thanks Dr Joe, you summarised my whole post in one line:

The stands sounds interesting...do you trust your design enough to fill the tank inside?

Question is, do I trust it enough to fill it inside AND have a 40G sump under it?

I wish I could enter all the details into a program, and have it point out potential weak point and alternatives... but alas.
I guess that's why I'm posting my design; So that others may help me identify those issues that I don't want after the tank is filled.

So let me know if you see any worries guys

 

[Lil_Stinker]

..... The outer dimensions will be 2440mmL x 650mmW x 1065mmH......

.....Glass will be 10mm with 2136mm x 550mm exposed glass(45mm minimum rebate around edges.) .....

I will use 18mm plywood. And braces on the tank will be 38mm x 114mm (2"x4") pine wood. As for the stand: I originally planned on doing a classic beam – and – ply stand. I now plan on doing the stand completely out of 3/4” plywood, just to prove a point.
I’ll post my findings when the tank is full and is standing on its plywood only stand. I should mention that the current stand design will consume 3 whole sheets!
......

US conversions
Tank
2440mmL x 650mmW x 1065mmH = 96" x 25.5" x 42"
445 US gal

Water Weight 3900 +
Foot Print = 17 sq ft
230 lb/sqft (water only)

Glass
10mm with 2136mm x 550mm exposed glass(45mm minimum rebate around edges.)

Thick ~ 3/8th (.3937 inch)
84" x 21.5" exposed
87.5 x 25 overall
1 3/4" relief

===============

As far as the stand, like I said above 230 + lbs/sqft

Thats quite a bit for 2 3/4 inch ply every 16 inches; that is the height of each beam? (not less than 15 cm{6 inches}), I hope.

I see you have beams 2 running at each pass, with a 3/4 gap in each. I say fill that gap & join the beams. perhaps even

The centre pass beam; if you are goin to make relief cuts to join them, will likely weaken the design, you will loose 1/2 the strength in the center. Think about an alternative, joist hangers perhaps, with a segmented centre pass beam.

I might even suggest go to 12 inch on center beams rather than 16..

Sistered plywood is plenty strong.. two 3/4 inch ply together beats a 2x4; but should be high pressure glued together.

Where you join the uprights to the beams.. the new middle board should rest on 1/2 the width of the upright. see image...

 

[Cyclop3000]

Well, I also question your stand design. Nice "design", but the strenght of the stand will not hold all this water. The center "beam" you put there will bend, if not break. That 3/4 plywood could be broken easily by pressing hard enough between the beams. Now I think what was mentionned by Stinker is a good solution to this.

It needs more strenght IMO.

Oh and you mentioned you were on a budget, dunno about where you live but here doing this plywood-only stand woulc be more costly than using 2x4 framing...but then proving a point is important

 

[Dominuslive]

Make sure you use a high quality wood glue. If you do the wood will break long before the bond. I have personally tested this(with a 20lbs sledge). Also, make your center support 1 1/2 " of 3/4 plywood gued together @ 4" of thickness, and should be no dropping or breaking. Also add some diagonals in there as well.

 

[Lil_Stinker]

Make sure you use a high quality wood glue. If you do the wood will break long before the bond. I have personally tested this(with a 20lbs sledge). Also, make your center support 1 1/2 " of 3/4 plywood gued together @ 4" of thickness, and should be no dropping or breaking. Also add some diagonals in there as well.

Please explain

1 1/2 " of 3/4 plywood gued together @ 4" of thickness,

I get 1-1/2 inch is two 3/4 glued, but where does @ 4" of thickness come from?

Is this 4 inches high? cause it shouldn't be less than 6 inches .. perhaps more...
This is going to be like 250+ lbs/sqft, it should be as strong as a floor...

& you don't want to notch the beams, use hangers

 

[ChrisGray]

looks like a good plan
i cant think of any reason why it wouldnt work

 

[Dr Joe]

Thanks Dr Joe, you summarised my whole post in one line:

Question is, do I trust it enough to fill it inside AND have a 40G sump under it?

I wish I could enter all the details into a program, and have it point out potential weak point and alternatives... but alas.
I guess that's why I'm posting my design; So that others may help me identify those issues that I don't want after the tank is filled.

So let me know if you see any worries guys

I asked chompers to take a look at it maybe he can shed some light too.

Dr Joe

.

 

[fatphatboy88]

That is a good design, I have never though of integrating the stand and Aquarium as one. The only concerns I see is that all of the bracing in the stand itself should be made of 2x4s and the corner posts and posts along the wall should be 4x4s.