My Plywood Tank

[marinelife]

I felt I should start a new thread for my tank.
Here is how it looks as of today:

Note the front is not glued/screwed in yet (hope to do that tomorrow)

The inside size of the tank will be 28-28.5" front to back, 96" long, and 75" high with the water level at 70"
The outside size of the tank will be 34" front to back, 100" long, and 78" high. Just enough to fit in the front door and the spot already missing wood in our wood floor. The tank will sit in the same place as my current 375 and on concrete. I will be using fiberglass and exopy on the inside of the tank. The front panel will be 1.5" thick and give you a good view of most of the tank.
The tank is made out of
7 48"x96"x3/4" sheets of A Grade Burch Plywood
7 48"x96"x3/4" sheets of A/C Grade Fir Plywood
All sheets are/will be glued and screwed together to get 1.5" walls

 

[MarkS]

Is that opening the viewing area of the tank? If so, I see a potential problem. The two squares in the lower corners will flex and twist in such a way that they will put a great amount of stress on the glass or acrylic. You do not want any sort of corner jutting into the viewing area.

 

[marinelife]

I do not think I understand????

 

[Mark426]

He is talking about the notch that is cut along the bottom. I have read the same thing...the glass/acrylic cant have inside corners like that. But... what do I know. Getting scuba tanks to go with that monster? Keep us updated as you progress....this is going to be a good one.

 

[marinelife]

hmm, I had not heard about that, I am interested to hear more!

 

[norskfisk]

I assume the 2 front panel pieces aren't fixed together yet, that is why the seam looks a bit weird. If you use double front pieces to get a 1.5" thick front then I don't see a problem with bending or flexing.

I am curious about how you will fix the acrylic sheet in place. I have never seen that being done before on a plywood tank. As you go along, please tell us about the products you use and take pictures.

 

[Horace]

im just trying to imagine why you would even want those corners there? Assumming your front panel is going to be one sheet of glass (cant imagine how else you would do it), your not saving any money by cutting out those corners, and if you dont plan to cut them out, why block them off so you cant see in there?

 

[mille239]

I too am confused! It looks like it will be a great project, but 70" deep?!?!?!? Do you know what kind of pressure that will place on the plywood. It will bow like a baloon without 2x4 or 2x6 reinforcements around the plywood. Not to mention, how do you propose to clean this tank?

I don't intend to come across as negative, but would just like a little more information on your design. Thanks!

 

[MarkS]

<a href=showthread.php?s=&postid=12825194#post12825194 target=_blank>Originally posted</a> by mille239
I too am confused! It looks like it will be a great project, but 70" deep?!?!?!? Do you know what kind of pressure that will place on the plywood. It will bow like a baloon without 2x4 or 2x6 reinforcements around the plywood. Not to mention, how do you propose to clean this tank?

I don't intend to come across as negative, but would just like a little more information on your design. Thanks!

There is 1 PSI per 26" of water, so 2.69 PSI. He's doubling the plywood, so he is more than fine on that point. However, the two squares must come off.

 

[marinelife]

Thanks for the replies. I have no problem removing the squares, my wife and I toalked about it for a long time before I made the cuts. I have been talking with several people that make wood tank and no one said anything about them being an issue. They are there to 1. looks: tank looks different with them. 2. hide a shelf for my clam.
Neither of which is really important so the wood can be cut to show more.

I am currently looking at 1.5" sheet of acrylic for the panel and using a silicone that bonds as a waterproof seal. The panel will not be held in place by anything other than water pressure and a few wood braces. The acrylic will stay square just the wood will have the extra squares at the bottom for design.

I have 2x2 ripped in half for the corners.

 

[reef_only]

This is interesting and some differences from any flywood tank builds I have seen. I just wonder why it is so deep down and the tall portion below and above the display area. for the square cut, I imagine it could be ok but overtime it may force the acrylic to bow in the angle beside the uniform bowing which may cause slightly close-up viewing. I would cut the bottom 2 corners either in straight diagonal or curve diagonal or fancy shape line diagonal so it would give the same purpose with cooler look?

 

[marinelife]

I made the tank with way do to the space I have for it, a taller tank works better than a longer tank.

I have wood at the top and bottom because the pael is 96x48x1.5 so I somewhat centered it. I have looked at 96x60x1.5 but the price it alot higher for only getting around10" viewable space

 

[dantimdad]

I really like the look of that.

Although I do normally like longer, more shallow tanks, I think this will look more natural when you put the higher light corals at the top.

This thing will be as deep as some natural reefs!



dantimdad

 

[geraldwhite]

From my understanding here the acrylic will not be cut to the shape of the hole but will be left as a rectangle. So those squares will have a lot of silicon and acrylic behind them. He will be using Epoxy and FG on this the PSI rating for the epoxy he is using is insane!

However I would cut the squares out to get a better viewing area, having paid for that large sheet of acrylic I would want to see every penny of it

You should hide your shelf in some rock work or make your shelf look like rock.

 

[masharp1126]

Very interesting, can't wait to see how it progresses.

My plywood tank has been in the works for about 12 months now and finally started the epoxy/fiberglass last weekend. Guess I'll have to start my own build thread before too long.

 

[cscr212]

This is going to be an interesting project.
What are your plans for a sump system and water flow?

I would also like to know what you plan to stock the tank with.

Thanks for sharing.

 

[reef_only]

<a href=showthread.php?s=&postid=12827603#post12827603 target=_blank>Originally posted</a> by geraldwhite
From my understanding here the acrylic will not be cut to the shape of the hole but will be left as a rectangle. So those squares will have a lot of silicon and acrylic behind them. He will be using Epoxy and FG on this the PSI rating for the epoxy he is using is insane!

However I would cut the squares out to get a better viewing area, having paid for that large sheet of acrylic I would want to see every penny of it

You should hide your shelf in some rock work or make your shelf look like rock.

I think this is what people are talking about that the pressure that the corner square applies on the acrylic is not uniform and the free corner of the square will tweak more and pulling the acrylic with it. IMO it may just give very little more non uniform bowing but not much problem out of it.

 

[marinelife]

These will be moved over to it once it is complete
Hippo Tang (donated to me by a friend in 2005)
Hippo Tang (purchased 1995)
Yellow Belly Hippo Tang (added March 2008)
3 Green Chromis (1/2001)
1 Green Chromis (May/2007)
5 Green Chromis (added Feb/2008)
Regal Angel (added March/2008)
Orange Shoulder Tang (April/27/2007)
6-line Wrasse (1/2006)
Chocolate Tang (May/2007)
Red Sea Emperor Angel (June/14/2007)
Sailfin Tang (May/2007)
Yellow Tailed Angel (April/19/2008)
Flame Fin Tomini Tang (May/2007)
Coral Beauty (May/2007)
Male and female Orange Anthias (Lyretail) (added Feb/2008)
1 female Blue Eye Lyretail Anthia (April/19/2008)
1 female Blue Eye Lyretail Anthia (April/21/2008)
1 Female Unknown Lyretail Anthia (April/2008)
several Serpent Stars
few Hermit Crabs
few snails
Variety of mushrooms
Acroporas
Montiporas
Turbinaria
Montipora foliosa
Fire Coral
Derasa Clam(5/2001)
Crocea Clam (3/2006)
Tear Drop Maxima (5/2006)
Derasa Clam
other SPS Corals


The sump will be in a closet on the end and flow will be 4 tunze streams and maybe a closed loop.
I am still looking at the square issue and my remove them if needed.

 

[marinelife]

What are your guys/gals thoughts for wood filler to match once the stan is on.

 

[MarkS]

The best option is thickened epoxy. Are you going to use clear epoxy paint on the visible wood or tinted?

<a href=showthread.php?s=&postid=12828801#post12828801 target=_blank>Originally posted</a> by reef_only
I think this is what people are talking about that the pressure that the corner square applies on the acrylic is not uniform and the free corner of the square will tweak more and pulling the acrylic with it. IMO it may just give very little more non uniform bowing but not much problem out of it.

Yes, that is what I'm talking about. The thing is that acrylic "remembers" stress. Typically, you get microscopic stress fractures which leads to crazing which leads to blow out. Once you see the damage (crazing) it's too late.