# Largest Non permanent Plywood tank build?



## blueinfinity (Jul 17, 2003)

Garf.org sets a lot of limits
I was looking to build a plywood tank at

8'L x 2'W and 2'H..

giving me 350 gallons roughly.

Sinc eI would need to move the tank some day, I was thinking of building this with 3/4 plywood and framing the whole thing with 2x4s on the sides back and around the front opening.

But I am wondering what the largest built people have seen is?
I figure If I build a frame and blue it to the frame, beefing up the tnak, and then fiber glass the inside,

This would also allow me to run all my plumbing INSIDE the walls to the underside for a sump,

Any advice on the matter would be great!

Thanks guys!

Shawn


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## mithesaint (Oct 31, 2006)

Maybe I haven't had enough coffee yet, but I don't think I understand your questions. It seems to me that most plywood tanks are built similar to your proposal. By saying "non-permanent" do you mean free standing?? I know a lot of people that have their tanks incorporated into a wall to give room behind to work on the sump etc.

I'm in a bit of a similar situation, as I know I'll be moving in the future, and want to build a big tank. I'll be watching your thread. Good luck. :thumb:

I have a link at home on my computer on how to build a modular tank, but I don't think that's the technique of choice. Others with more experience may have better advice.


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## blueinfinity (Jul 17, 2003)

well a lot of these guys build there tank in place, on a large stand, or into a large stand

I'm trying to decide if an 8 foot long tank once build will be solid enough to be picked up (by a few people I know) and moved if needs be.


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## mithesaint (Oct 31, 2006)

Gotcha. I would assume it would be stiff enough to support 350 gallons of water, a careful group of friends would be able to move it without destroying it. That's assuming they could handle the weight, which would be no guarantee. The glass I have for my monster is pretty heavy by itself. If you're planning a tank around the probability of moving the tank, you might want to look at integrating handles into the structure of the tank.

On the other hand...unless you KNOW that you are moving in the near future, just build the darn thing and worry about moving it later. You can always salvage the glass and build bigger after the move :lol:


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## blueinfinity (Jul 17, 2003)

oh i know im moving

and in reality the tank will probably never be filled untill i move

(within 1.5 years from now)

so I would be building in my garage with the intension of loading it into a truck and moving it lol

so designing an easy method to carry it.. hmm.. may be a good idea.

and if i dont fill it here. I will not be placing the glass untill after the move

But I guess, with it being able to hold 350G I would also assume it could handle a move heh.


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## Toby_H (Apr 15, 2005)

Last year I began building a double stack of plywood tanks built into their standâ€¦ The tanks were approx [email protected]â€™ tallâ€¦

I got the entire frame built and walled in the back/bottom & sides of both tanks. I also made a couple other smaller projects to familiarize myself with the materials I would be sealing with (HardiBoard & Drylock).

I decided that before filling it in the houseâ€¦ I would want to test fill it in the garageâ€¦

I believe I could build it to hold water perfectlyâ€¦ but I highly suspect the process of filling itâ€¦ draining itâ€¦ moving it (into the house)â€¦ then refilling itâ€¦ was very likely to create a very minor crack in the sealant ruining the whole projectâ€¦

Fiber Glass Epoxy dries extremely brittle and the thicker it is, the more brittle it is. I have worked with this stuff before and would never (again) try to seal a plywood tank with itâ€¦

Now I am using my stand/tanks as one very sturdy work bench in the garageâ€¦

Adding and removing all of the water makes a huge difference in pressureâ€¦ and therefore in settlementâ€¦ If there is uneven settlement there is a very high risk of cracking. This is called differential settlement in the construction world. Differential settlement in soil beneath a house/building can cause major failures in the foundationâ€¦ One board sagging more than you expected could do the same thing to your plywood tankâ€¦

Yet after all of that Iâ€™ll admit I apply engineering overkill to all of my projectsâ€¦ Especially on projects where I cannot afford failure


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## fishwolfe (Mar 27, 2005)

i was thinking of using the fiberglass resin to seal a plywood tank.but as mentioned above,i changed my mind.im going to use this instead,http://www.pondarmor.com/


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## blueinfinity (Jul 17, 2003)

Toby I can see your point, I was honestly thinking of going with a roll on pond liner (cant recall the brand atm)

Which would allow a bit more flex, as well. I would not be filling the tank untill it is in its final resting place. and there for would not install glass untill the same time (cutting down on weight)

I apply overkill as well. for example:
I just build a stand for a 90 gallon all glass tank and build it out of 2x10 haha  on 10 inch on center with 2 3/4 sheets of plywood on top with a 1/2" of foam.

Pretty sure I could park a car on this thing 

Leg bolts, glue and a lot of deck screws would be the way I go. ensuring theres no room for moving/twisting.

Shawn


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## SLIGHTLY STOOPID (Dec 23, 2004)

8 x 2 x 2 is basically a 240 gallon. Reef Central has a good Tank Volume Calculator


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## fishwolfe (Mar 27, 2005)

so do we in the library


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## SLIGHTLY STOOPID (Dec 23, 2004)

True, but it converts to metric and cichlidforum is mostly readers and posters form the USA. We don't use metric.


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## blueinfinity (Jul 17, 2003)

SLIGHTLY STOOPID said:


> 8 x 2 x 2 is basically a 240 gallon. Reef Central has a good Tank Volume Calculator


my bad

I was looking at a 3 foot high tank
but with more looking I may just make it a bit deeper and keep it 24 high

maybe a 30x30x92 or such


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## fishwolfe (Mar 27, 2005)

it also has conversions from metric to inches and litres to gallons. :wink:


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## Stickzula (Sep 14, 2007)

I think I saw a post where someone made a modular plywood tank that could be taken apart and moved. The idea was to build the panels individually and coat them with epoxy. Then screw them together and use silicone on the joints where the panels came together. To move it you would cut the silicone and unscrew it. I didn't look too closely at the design, but it had 2x ribs sandwiched between 2 layers of plywood. Kinda like a boat hull. I believe that the ribs on the ends of the panels is what got screwed together. Sorry I don't have more info, but maybe this will help.


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## Stickzula (Sep 14, 2007)

> 8 x 2 x 2 is basically a 240 gallon. Reef Central has a good Tank Volume Calculator


If you are mathematically inclined you could use the following conversions.

Volume = LengthxWidthxHeight

1 inch = 2.54 centemeters

1 foot = 0.3048 meters

1 cubic inch = 0.004329004 gallons

1 cubic foot = 7.480519 gallons

1 gallon = 3.785412 liters

1 cubic centemeter = 0.001 liters

1 cubic meter = 1000 liters

1 liter = 0.2641721 gallons

I could go on and on, but I think that with these conversions you could figure out what you are looking for.


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## blueinfinity (Jul 17, 2003)

lol i just look online

I guessed a tmy size anyway

I do not want modular, i wouldnt trust it.. Basicly I plan to build as big as I can get down some stiars hehe

so 8foot by 3 foot deep by 30 inches tall may be ideal for cichlids


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## mithesaint (Oct 31, 2006)

Sounds like a great size for cichlids, lots of room for different territories.

Since you already know that you're moving, just hold off on sealing it before you move. You can build the whole structure, but hold off on your waterproofing till you're at your new place.

Just an FYI, I've been told that pond liner or whatever it is is not a great choice for a liner as it doesn't seal well to glass. Issues with the silicon not sticking or something like that. Might want to look into that a little further.


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## blueinfinity (Jul 17, 2003)

actuall ynow that you mention it. I think i remember hearing the same thing. hmm

I will maybe even contact the company and see what they recomend.

Shawn


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