Bolt together Fish Tank

[Daniel Bodily]

I would use polycarbonate for the main tank it is too soft and will scratch. Pro and cons of acrylic, polycarbonate, and glass
Glass the most scratch resistant and the most brittle.
17 X stronger than glass, Acrylic is good on both scratch resistant and brittle and is the clearest.
250 X stronger than glass, Polycarbonate is the strongest and least brittle but is softest for scratches.
Doesn't warp and is really easy to work with tools

 

[Daniel Bodily]

I'm planning to seal with something that is used to make polycarbonate airtight at 3000 PSI. It a 100% silicone O-ring rod that comes in a roll.

 

[ebushrow]

I really want to use polycarbonate for a sump tank and there are really good glues for polycarbonate but non that I can find that are fish safe. IPS weld on 2 part for acrylic is one of the best but not sure if it's works as good on polycarbonate as acrylic. It says that you can use it for polycarbonate to attach to acrylic. But I don't know how strong that bond is. So I have titanium screws and A full CNC mill that will make it easy to build and I'm going to try it

I wasn't saying not to try it, I just didn't understand the need....by all means go ahead and give it a try...

 

[Daniel Bodily]

Thanks LOL :confused::confused::confused:

 

[kalare]

Just because the polycarbonate is a strong material doesn't mean that strength transfers to a system where you are depending on screws and their threaded holes to keep the tank together. I've not seen where you are saying what size of tank you're planning on building? Even say a 30g tank has quite a bit of force pushing out on those walls which then will directly transfer to the screws holding it together. To do this safely, I'd say you'd need a panel thickness of at least 3 times your screw diameter to allow for enough material left on either side of the screw once the holes are drilled and tapped. In addition, you'll want the most available area for a gasket to seal. What type of screws will you be using? I wouldn't recommend nylon, the threads might rip out.

The amount of force on the front panel per foot of length of the panel will be approximately equal to 62.4 * the height of your tank * the height of your tank / 2 (that is the height of your tank, squared). To get the force needed to transfer to one side of the front panel, you would multiply that number times half the length of the front panel. This force is independent of the width of the thank, the force will be the same whether your tank is 6" wide of 60" wide...it's all about the depth. That being said, I'd recommend trying this with a shallow tank.

I think for a sump this might be doable, however I'm not sure I'd try this for a tank with water deeper thank 12" or so.

Good luck!

 

[Daniel Bodily]

The only reason why acrylic is used on main tanks is because it is clearer and more scratch resistant. But like I said we build 3000 psi air tanks that are the gasketed and screwed together out of 2 " thick polycarbonate, but everyone thinks that 33 psi of water will not hold. I just think this is funny that because you haven't seen it then it's a bad idea. The only problem with that is all the high end skimmers use this same idea in there design with polycarbonate gasketed and titanium screws because it doesn't warp. Also polycarbonate is used on most leads of sump tanks to stop warping
And for force the air tank is 216 tons per square foot or 432,000 pounds per square foot or 196,6363 KG per square foot. Leaking will not be the problem at all even if it was a 3000 gallon tank 50 inch tall tank that is still only 165 psi at the bottom or a force of 11.88 tons per square foot or 23,760 pounds per square foot,10,800 per square foot not even close to the force invalid with the air tank. Air is a small molecule also

 

[Swoody]

Here's a few pics of a bolt together I made on the fishing boat I work on in the Bering Sea... just a keeping busy project for me....made a constant seawater supply and just had it continually overflowing to deck... at the end of each trip we threw them back in and started over....

 

[Daniel Bodily]

Sweet thanks

 

[Dom]

I don't want this. Bolt will never do this and nothing can easily be change when glued

Holy mackerel (yes that was a pun)!!!

 

[Dom]

If you have a wife and this thing explodes....I hope she is understanding....mine would have me put it by the curb and lock me out with it.

LOL!!!

 

[Dom]

Here's a few pics of a bolt together I made on the fishing boat I work on in the Bering Sea... just a keeping busy project for me....made a constant seawater supply and just had it continually overflowing to deck... at the end of each trip we threw them back in and started over....

Now that's cool!

 

[justingraham]

I would only be scared of the bolt head snapping. I think what ur doing is fine but I think the pressure would snap the bolts.

Even when u use weld on 3 on acrylic acutially now that I think about it any good weld no matter the material where the material is welded together it is stronger the actual material itself.

Meaning if two pieces of say acrylic welded together properly is strongest at the joint

 

[Daniel Bodily]

There is only one problem with that polycarbonate is 136 times stronger than acrylic. And all the pictures of failed tanks it's never the acrylic that has broken even the guys in vegas that are they also break the glue

 

[justingraham]

The seam breaks because of a bad seem with air bubbles in it or not applying it properly.

If u weld to pieces of acrylic together properly and try to break them the acrylic will break before seam does.

Same thing when u weld metal. If u weld metal together properly it will never break at the seam.

I understand what ur trying to say but it doesn't matter how strong u are so what if u can bench 300 lbs if the compition is leg presses.

I also believe tanks have been built the same way for decades for a reason. Do some break yea that's the nature of the best tho. Ur idea of bolting a tank together is new and interesting to me but I think it leaves to much room for error: esp if the only reason u are doing it is to take it apart do u can clean it. Ur going to need gaskets and a whole bunch of other stuff and then when u do take it apart to clean it ur going to have to replace everything with new gaskets and seals cause it won't seal the same way.

But good luck man I hope it works out the way u want it too

 

[Daniel Bodily]

That last post was bad sorry about that
Ok so I did a test today at work
1/4 acrylic tube 6" diameter with 1/2 inch end cap acrylic glued with weld-on 2 part
1/4 polycarbonate tube with 1/2 inch end cap polycarbonate glued with weld-on 2 part
And 1/4 polycarbonate tube with 2 mm cap screws and 1/2 end cap

Acrylic broke first at 239 psi the tube broke
Polycarbonate with glue got to 412 psi end cap
Polycarbonate with 2 mm cap head screws got 1700 + psi tube broke

 

[Daniel Bodily]

No air lose from the silicone 1/64 gasket in a competition grove

 

[Daniel Bodily]

Thanks for all the thoughts I will send pic when I get it completed in the next two weeks

 

[kalare]

I don't think most people are telling you it can't work, only worried that you take the proper precautions to make sure that it does. No doubt polycarbonate tanks can hold thousands of gallons if designed properly and of the proper thickness. I think most are worried about the joints to be honest, not the material itself failing. I would only caution that you have enough gasket area around the screw holes, but it honestly sounds like you know what your doing :)

Good luck and let us know how it goes.

 

[Daniel Bodily]

:):):):):)

I don't think that most people are telling me it won't work. It was more or less what I thought I would get from most people. Most of the population don't think outside the box. I got almost 70% thinking it is a bad idea. I thought that it would be closer to 80%. I was already moving forward on building the tank. The Polycarbonate will be in next weekend I will machine it over the weekend and put it together some time the following week.

:):):):):)

 

[becks]

Could you not just use glass and use a metal brace top and bottom to hold the plane of glass to prevent it giving way? Then hide the metal trim with a wooden fascia?