2 piece tank ideas

[earthstudent]

I have been going over tank designs and sizes for my next huge build. I am now planning a 8'x8'x2' tank 957g. I have no problem up scaling my original 8'x4'x2' plan but the issue I am running into is.. I do not want the tank to be permanently in the house I am going to build it in. I want to be able to move it when the need arises. So I am thinking now 2 tanks of my original size connected to make the larger tank. Basically a 2 piece tank with some sort of joint down the middle.

My original Idea is to use 1/8" ABS plastic as a liner with solvent welded seams and an acrylic window. Now there needs to be a seam down the center of the tank, parallel to the viewing window, basically jointing 2 8'x4'x2' tanks without the wall between them. Make sense.
I am thinking a gasket of some fashion between the tank seam where the 2 halves get bolted together.

Can you all throw me some ideas please.

I know the easiest way to do this is to use a pond liner but I do not like doing a viewing window with a pond liner unless someone can tell me a good way to do this? There must be a viewing window.

 

[Satan's Goldfish]

A good rubber gasket where the 2 halves meet with lots of nuts and bolts through all the way around, evenly torqued up should do the job. I'm not the best with CAD otherwise i'd draw you a picture. The pressure of the water would always be trying to push the 2 halves apart so the bolts would need to be proper chunky ones and lots of them evenly spaced. Would probably go for a metal rather than wood lip where the gasket is and the bolts run through.

 

[earthstudent]

That was my idea. I was thinking 3/8" or 1/2" bolts (possibly stainless) spaced about every 4 inches with a large thick washer on both sides. I am not sure about the gasket but I am sure I can find something.

 

[fg4608]

You are talking about having the bolt flange external, right? I have not reviewed your current design but that would be how I would do it.
Also, keep in mind the different grades of nuts and bolts as well. Go with the good stuff (the actual numbering escape me for the moment but it should be easy enought to find out).
I would def. use blue loc-tite on each nut as well, or a jam nut, to make sure that they do not loosen over time. Thinking about it, a jam-nut might be the better option since you would want to be able to re-tourqe them every now and then.
If you want to get really ambitious, use Bolt-Washer-tank-washer-spring-washer-nut-locknut... That would be a self tightening assembly but your hardware cost may run away from you a tad to much

Either way, I like your idea! It is super simple and I may have to use it myself now as I am in the tank planning stages myself...

 

[pjsmetana]

... keep in mind the different grades of nuts and bolts as well. Go with the good stuff (the actual numbering escape me for the moment but it should be easy enought to find out).....

Grade 8 is the strong ones

Its also the ones I would use as they are the least prone to stretching.

 

[dawnmarie]

Along with proper fastener torque, bolt pattern and gasket material there are a few other considerations.
The connection of the flange to the tank itself is just as critical if not more so.
The vertical connection/seam will also have to withstand bowing out as this is now a built in weak point.
I have been toying with a similar idea. What would you all think of this method :

This would run perpendicular to the standard framing.
$ .02

 

[pjsmetana]

I don't like the idea of the metal being on the inside of the tank. I don't know how else you would do this though.

 

[dawnmarie]

I agree, I just can't visualize how to attach the flange to the tank without fasteners ( in single shear) or a clamping plate being inside the tank

 

[fg4608]

I don't have a 100% clear picture in my mind but I do not see why the metal cannot be sandwiched between plywood and only structuraly supported to the outer layer... (In other words Sheet the metal on the inside) Then you should be able to seal the slight gap with silicone...

 

[fg4608]

I have a quick sketch of a possible solution but I'm a noob and need direction. Please point me in the direction of how to post pictures...