# Making one tank out of two



## cosmiccow (Jun 10, 2007)

I want an eight foot tank and have two 55 gallon tanks that I'm thinking about taking apart and making one. Has anyone heard of such a thing? I was even thinking taking just one end off each tank and attaching them end to end somehow?
I would leave all the original trim on the tanks (except the open ends of course) and then make a new bottom and top frame to secure the two tanks as one. The big question is the joint and how to seal it?
Is this crazy?

Tony


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## MalawiLover (Sep 12, 2006)

the center seam will not hold against the water pressure when filled


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## Riceburner (Sep 3, 2008)

What if it was wrapped in a metal band? a complete ring....say a 3" wide one and siliconed on to boot.


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## planenut007 (Mar 21, 2009)

Sounds like you are going to need a carpet shampoo machine soon, or at the least a good wet/dry vac...I am not that brave


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## Stiletto (May 17, 2009)

Depending on how much effort you want to put in to it, you could do it plywood style. Re-use the panes of glass from the 55s as the viewing panes for the plywood tank. If I didnt live in an apartment I would so build a plywood tank.


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## cosmiccow (Jun 10, 2007)

Thanks for the replies!
I was thinking that at the seam I would take two panes of glass and sandwich the seams in between. I would also construct a cross brace at that point for stability. I do feel brave and hope to make this in the next few weeks.


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## planenut007 (Mar 21, 2009)

Good Luck, keep us in the loop.
I would like to try maybe a four panel corner plywood tank someday, somewhere around 300 gallons or so, but got to convince the wife that we need it first.


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## padlock 08 (Jul 31, 2008)

if he had a steel brace at the seam croosing the tank and a steel brace surrounding the tanks bottom, would it not hold?


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## jontwhale (Mar 20, 2006)

have you considered a water bridge~?


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## cosmiccow (Jun 10, 2007)

Well I now have a 8 ft. tank in my basement! To summarize; I bought two used 55 gallon tanks and then removed one end from each. I bought some cinder blocks and 3/4" plywood for my stand. After assembling the stand I joined the two tanks together with silicone and a couple of glass strips across the seams for strength.
My total cost so far is about $140.
I will post a picture soon. The main downside with this is that I have an ugly seam in the middle of the tank. But since it is in my basement (soon to be fishroom) appearance is not so important.
One last note, if you have ever tried to remove a panel of glass from a fish tank, be prepared to work at it! After a lot of work I managed to get one end off clean, the other tank I broke the glass.


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## vaypourus (May 20, 2008)

I'm curious to see how this will hold up after time. There are three big problems that I see here:

The glass thickness on a 55 is designed to withstand the pressure of 55 gallons of water. An 8ft tank will generally have substantially thicker glass, as the weight of 110 gallons is substantially greater per square inch of glass. My 55 has glass that is 3/16" thick...an 8 foot tank using your dimensions recommends glass that is at least 3/8" thick, and preferably 7/16" thick (that is a factor of over 2x greater than what you have!)

With 8 feet of glass, the weight of the water is going to cause the "glued" sections a lot of outward force. With a single sheet of glass, your weakest part is the center of the glass where it will bow out. This is why center bracing is so important. You have created a seem at the weakest point on this tank.

Even though you have sandwiched the panes with other panes of glass, I could still see this force forcing apart those seems.

Third, much of the strength in a glued seam is that the pieces of glass are adjacent to each other. It has been a long time since my mechanical engineering classes in college and I don't even remember the names for the forces, but I can assure you the strength comes from the corner. You are not getting this benefit gluing the pieces of glass together end wise.

I don't mean to put down your idea, but this is something that could end in disaster. I'm not saying it will...**** it might hold up for ever. In theory however, this is a bad idea. There is good reason you don't see this done elsewhere.


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## cosmiccow (Jun 10, 2007)

Hi, 
I too am curious to see how it holds in the long run! I'm keeping the tank at 18" of water for now.

I did preserve as much center brace as possible on both tanks and then bonded then together. I think my new center brace is just as strong as the original. 
Just FYI.
The forces on the sides of a 48x20 tank come out to 346 lbs. For a 96x20 tank it is 691 lbs. 
Kind of scary huh?


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## Riceburner (Sep 3, 2008)

pics pics pics....


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## cosmiccow (Jun 10, 2007)

Not real pretty, but I'm working on it!


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## Riceburner (Sep 3, 2008)

whoa...I thought the seam cover/brace would have been more substantial. I'd be concerned that the patch is too narrow. Hopefully it holds. Keep us updated.

...hmmm...wonder if two 33G 3' tanks would make a good 6' one????


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## gtphale (Oct 12, 2008)

is that water at the front of the tank or did you silicone the tank to the plywood?


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## vaypourus (May 20, 2008)

Riceburner said:


> ...hmmm...wonder if two 33G 3' tanks would make a good 6' one????


No. See above post.


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## Riceburner (Sep 3, 2008)

yeah I was kidding. I'm not about to try it. I'd rather have a proper full 6' tank with thick enough glass for the span.


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## planenut007 (Mar 21, 2009)

That block is not designed to hold weight in that configuration, flood waiting to happen, set the blocks on end with holes in center like used when building, much safer.
Tank looks good as long as it hold, maybe some wood trim ???


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## magic_cichlid (Jun 30, 2003)

Was just searching the forum and came across this. Did it end up holding up? Just curious...


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## manbou (Sep 20, 2012)

The max PRESSURE of tank is under 1 psi (bottom of tank). As long as the glass doesn't bend it should hold.


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## manbou (Sep 20, 2012)

P = p * g * h. Were P is pressure, g is force of gravity, and p is density of fluid. P = dF /dA; dF = P*dA. Total F bottom = Volume * g * p, and F side = h^2 * 1/2 * Length * g * p.


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## bibbs68 (Dec 1, 2006)

I saw this tank in a thread on another forum but can't find it again. 

But, here is one for those that want to join tanks, two 55's and a 29.

http://www.monsterfishkeepers.com/forum ... -feet-long


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