Fish Tank Design - any good?

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Hi all. I haven't posted here in awhile. I was thinking of making a tank stand for a 75 gallon fish tank, which will weigh well over 700 lbs. What do you think of this design? Are there any major problems with what this guy has done?
http://www.arbreptiles.com/cages/75g_stand/index.shtml
Thanks for any suggestions, dwhite
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Dan White wrote:

No problems, but I think it's overkill. So far I've built two stand,one for a 29 gallon out of nothing but 3/4" plywood, and one for a 40 gallon out of standard 4/4 hardwood.
Most hardwoods are quite strong in compression. Even for a 75 gallon I suspect 2x4s and 4x4s are overkill. I'd build with 4/4 making sure I had at least two internal vertical dividers for a tank that size. I used one vertical divider for my 40 gallon.
Check some values for the strength of the wood you're planning to use.
--
It's turtles, all the way down

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at
I'm not sure I understand. Are you saying you would make a frame entirely out of 4 by 4's, or would you do it the way the guy with the website did? I don't think this is what you were intending to say.
thanks, dwhite
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4/4 Is spoken as "four quarter," for nominal one inch stock. 4x4 as in "four by four," for nominal dimension, is a different animal.
For a single tank and with glued sheet goods to reinforce, the 4/4, which is really 3/4" thick hardwood would be rigid enough and support anything you wanted to put to it as a static load. Carry your legs right up to the top rails and use joinery that tries to compress the end grain and you'll do fine.
Any construction-grade "S-dry" stuff you get will do the pretzel imitation as it cures down, possibly warping enough to drop a corner or raise a center and cause your aquarium to leak. BTDT in the days of metal frames.
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is
Just to be clear, you are recommending that I glue, not screw, the panels to the frame?
Carry your legs right up to the top

I'm a bit new on the terminology. Can you rephrase what you mean by "joinery that tries to compress the end grain"?

center
Again, you're talking about the glue used to attach the side, front and top panels to the hardwood frame?
Thanks a bunch, dwhite
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Yep, sheet goods are stable enough in short runs that they can be glued in place. Idea is to use them as filler and gusset both, though you could float the panels and gusset under as well.

The plan you referenced shows it pretty well. The rails ride on the end grain of the 4x4s. Wood is stronger that way. Of course, softwood, especially softwood of construction grade and questionable moisture can make that wrap lap into a loose joint in half a week by drying and contracting. It may also compress enough on the face grain of the rails from bumps and/or an uneven floor to become loose as well. Thus the recommendation of hardwood with its greater face strength and gusseted or glued panels.

Nope, construction grade "white" wood stored in the rain is more a work in progress than a project maker. It's going to move a bunch as it adjusts, and it's often cut from the worst kind of stuff, just to make that worse.
Oh yes, nobody's recommending you use 1" square lumber, least of all me. But 3/4 by 2 1/2 will take a hell of a load against the 2 1/2 dimension over a span of four feet. More, if you brace it in the middle.
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OK, that makes more sense. BTW, this would be for fresh water. I've done the marine thing, and am just not up for that.
Thanks! dwhite

which
you
panels
do
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and/or
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over
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Hi Dan, All,
I am in the same over-engineered planning phase. Here are some drawings of what I am going after...
http://i62.photobucket.com/albums/h108/leecherubin/skin_doorsopen.jpg
http://i62.photobucket.com/albums/h108/leecherubin/small2x4Iso.jpg
http://i62.photobucket.com/albums/h108/leecherubin/small2x4Top.jpg
http://i62.photobucket.com/albums/h108/leecherubin/small2x4Front.jpg
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WOW. Those are great drawings. Looks like it is exactly for a 75 gal tank, too. Have you settled on this construction design?
dwhite

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I have settled on this design. You could use this for 75g or 90g, as they have the same footprint. This will be my biggest woodworking project to date, so I think I'm in the same boat as you. I do have access to a friend's tools, so now I just need to learn how to make the dado cuts for the lap joints. :)
Drawings were done using Google Sketchup.

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Dan White wrote:

"4/4" means rough cut lumber 1 inch thick (it's measured in units of 1/4"--4/4 is 1 inch, 8/4 is 2 inch, 5/4 is 1-1/4 inch etc), which normally dresses out to 3/4 or so.
Even plain old white pine has a compressive strength of over 4000 PSI when applied parallel to the grain. Perpendicular to the grain though it's only a tenth that strong, but even then 3 square inches would support the entire weight of the tank with enough margin for aircraft design.
--
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--John
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I have built all my tank stands, tanks I used to have: 85 gallon, 55 gallon, 45 gallon, 40 gallon.
Don't use any woods that have been "bonded", stuff like particle board will swell when soaked with water. So what that guy used for the bottom of his stand is a no no. And yes you will spill water on it especially if you have a sump located inside. When the particle board expands it will throw off any "levelessness" you have.
I would say that plywood is ok as the glue is only exposed on the ends of the sheet not through out like particle board and that stuff he used, which I think is called sheathing (someone will correct me, the name of it is slipping my mind).
He also put treated lumber for the corner posts from the looks of it. That also isn't necessary. In fact I'd go so far as to say that 4x4s aren't necessary. The weight of the tank is distributed evenly so there is just as much weight sitting on those 4x4s as there is on the 2x4s in the centers.
Look at this way at 75 gallons of say salt water that's a total weight of about 750 lbs. If you used 6 2x4s that's only 125lbs resting on each 2x4. I'm a fat guy at 260 and I wouldn't have a problem standing on a 2x4 up ended and fear it's breaking. So long as I could actually balance on one. Or better yet go to a fish store and look at the construction of a stand for 75 gallons.
I have always preferred a solid top like a table vs. the open ended stands.
When you cut the 2x4s that are the supports make sure they are all even with each other.
I will say his end product is very nice looking and kudos for the DIY site. Though I personally would have laid the plywood vertically so the grain was going up and down not side to side.
One more note once you get the sides, back and front (minus the door) on you will eliminate side to side and front to back movement. So keep this in mind when you build the frame and it seems shaking it'll be solid once done.
On the center pieces he has steel T brackets, when I did mine I laid 2x4s flat and simply screwed right through to the vertical 2x4s.
Lastly, 2 measurements are important. One the overall height, nothing works better on algae removal than a razor blade so once built you want to make sure you can reach the bottom back of the tank.
Two the internal space. Make sure you have enough room for skimmer height, sump height and sump tank width and length. It won't matter much on a 75 or larger but on the tanks that have the same width as a 10 or 20 gallon the sump won't fit. This is the main reason I got rid of my store bought stand for my 40L the damn sump wouldn't fit inside the stand.
You may know this but I'll state it anyway for you background on the tank use black those coral backgrounds and solid blue detract from the color of the finish and contents.
Good luck. You doing SW or FW? The two coolest things I ever had were an octopus and a stingray.
And overall cost for a stand that size is probably less than $50. Well worth the time and effort.
-Matt On Mon, 26 Mar 2007 21:01:19 -0500, "Dan White"

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Thanks for the comments Matt and everyone else, too.
One thing I'm a little concerned about with using 2x4's is the quality of the 2x4. I build a large commercial store counter with 2x4 from Home Depot. I had to search for the best 8' boards (even the A boards had some warp and twisting to them). Am I shopping at the wrong place, or do I just have to look hard enough to avoid the warped and twisted ones?
Also, would you cut out the tops of the 4/4 (if I go with those) to rest the 2/4 into as he did, or would you just brace and screw it together?
thanks, dwhite
<Matt In Fenton> wrote in message wrote:

tank
What
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Dan White wrote:

Just in case you haven't gotten, or read, some of the other responses, "4/4" and "4x4" are two different animals. The first is pronounced "four quarter" and refers to ordinary 1" stock, which is actually about 13/16". The second is pronounced "four by four" and refers to dimensional lumber which is actually 3 15/32" by 3 15/32".
And again, 4/4 is all you need.
--
It's turtles, all the way down

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Well, now we've all established my level of expertise (ie, not knowing the difference between 4 by 4's and 4/4). :)
I'm really surprised that you all are saying that I should be fine with stock that is less than an inch square. To be clear, you are saying that I can make a frame supported in a couple of places in the center, and then screw that frame into plywood or hardwood panels, add a solid top, and that will be plenty sturdy for a heavy tank?
thanks again, dwhite

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"4/4"
quarter"
second
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Dan White wrote:

Not exactly. Let's say your tank is 1.5' by 5'. Here's what I'd do. Make up four frame and panel assemblies 19" wide and as tall as I want tha tank to be. Two for the outside and two for the inside. Make the outside ones 1/5" taller than the inside ones to allow for a 3/4" rabbet top and bottom. Cut the 3/4" sheet goods 19"x60" and glue into the top and bottom of the outside frames. Space the inside frames equally and glue into place.
Now that's the simplified version. The width of the 4/4 stock used for the frames is a matter of taste but I'd probably use 3" wide stock.
Dan, it appears from some of your questions that you're a relative beginner at woodworking. Starting with an aquarium stand is a great way to get a lake in your living room. My suggestion would be to buy a stand or find an experienced woodworker to build one for you. If you're still interested in woodworking take some classes, read some books, build some things that aren't structurally critical. We all had to go through a few years of learning - and I'm still learning :-).
--
It's turtles, all the way down

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beginner at

in
in
aren't
Yes, you could say I'm a relative beginner. Although I'm not a kid, my only significant experience with building any kind of cabinets was with my store. We did a complete renovation ourselves, which required quite a bit of sub floor modifications, load bearing wall changes, as well as new partition walls. So, I learned a lot from this. I think the counter came out quite nice. You can see it here:
http://new.photos.yahoo.com/qstroker2004/album/576460762395681003
I also built our chinchilla palace, which you can see above. (I know, the doors aren't square to the framing - I borrowed the doors from an older cage I built...).
Being an engineer, I fully realize I'm no expert, and I might well just buy a stand for the tank. On the other hand, I like doing this kind of thing as long as I do it right (I do have access to a good table saw, and have everything else I would need). That's why I over research anything I do like this. It seemed to me that the guy who built the stand out of 4x4's was overdoing it, and I don't particularly want to move something that weighs as much as the tank to my new home when that time comes.
You made me laugh because I was looking at the tank location relative to the chinchilla cage the other day, and wondered exactly how far the tidal wave would wash up into the cage if the tank fell over in that direction. Ever see a wet chinchilla? lol
If I ever build this thing, I'll post a drawing of my plans before I do it. Hopefully I can get some tips that will keep the living room dry for a long time. :)
thanks, dwhite
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Don't use construction lumber. 4/4 (hard wood) hardwood framing would be my choice. Actually, was my choice when I kept fish. Main thing is a planar top. If this is made of proper material you can support the entire with sheet goods underneath. Spills are handled by the size of the top, which protects the base with an inch of overhang or so. A couple of my main stands (6 20H) began as open frames, then were covered, because it was easier on the floor to detect and wipe dribbles from the top.
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30 years ago, I built myself a cabinet for a 125 gallon tank. The base consisted entirely of good quality pine 2x4s with a 3/4" plywood sheet topping the base. I then built a floating cabinet without a back out of veneer quality plywood to encompass the tank and the base. It worked very well for the entire time I had the fish tank. Never any leaks or swaying or skewing of any type from the base.
For simple feeding or simple maintenance the cabinet had smaller access doors on the top. But it was especially handy because I could just slide the entire construction out from the tank/base for major cleanings or full maintenance of any type.
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Be careful of designs from a site about reptiles! Aquaria look a lot like vivaria and terraria but they're full of water and the weight issues are much more significant.
I'm puzzled by what's supporting the bottom glass in this design? The usual failure mode of aquaria isn't over-loading the glass, it's excessive point loads on the underside, where all the force from a narrow frame is in one small area.
When you fill a big tank (I mean a _big_ tank), watch it in polarized light and look for the stress patterns as you fill gradually. If it looks to have a local problem, fix it before continuing.
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