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?
Thanks for any suggestions,
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.
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.
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
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.
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.
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.
"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
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
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
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.
On Mon, 26 Mar 2007 21:01:19 -0500, "Dan White"
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?
<Matt In Fenton> wrote in message
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.
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?
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 :-).
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:
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
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
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.
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.
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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