Tile-Top Stand for 40B Tank

[Walking_Target]

I'm in need of a new stand for my 40B.

 

Let me explain further. The stand that I originally built, while quite suitable and well purposed as a table, lacks a completely level top and thus is a cause for concern. Basically, while the stand is rock solid, one corner is about 1/16" out of true and the tank itself has been shimmed in that corner. While this theoretically *should* be perfectly acceptable, I don't believe it is.

 

The problem lies in the fact that I don't do finish cabinetry. I have plenty of experience in quickly knocking together tables for work sites, but little to no experience in making something that one would consider furniature. That and this stand was put together quite literally the night before the tank was put on it - short version of the long story: I rescued a large pufferfish from someone who would have otherwise flushed it. So it's not the best stand, but the house will fall apart before the stand does - 3/8" plywood top, 2x6 runners and 4x4 cedar post legs all held together with wood glue, 4" screws and liquid nails.

 

What I do know is framing, flooring, drywall, panneling, masonry and tile.

 

Now, my thoughts are to build a new stand, capable of supporting the tank, being leveled independantly of the floor to a limited degree and having a completely water proof tile top.

 

The basic design is a framed box (the cabinet) resting on top of a 2x4" frame that will support the weight of the tank. Based on the standard safety factor given for tanks of this type, you're supposed to count on a minimum of 10lbs per gallon of water (an average 40B holds closer to 45g). This accounts for a certain amount of equipment, substrate, rocks and the glass itself. The tank as it is now holds around 42 gallons of water, plus 30lbs of sugar fine sand, and the glass weighs about 50lbs. In the future, this will also have a sump system, so we're counting on another 150lbs or so of weight for that, so the design parameters are for aproximately 550lbs worth of tank. Broken down, that's roughly 140lbs on each leg if I were to use a 4 leg stand. To me, this is unacceptable, as that is a great deal of point-load on one area, so the weight will have to be distributed on a lowe frame, probably using 5 legs, with a cental post in the back of the stand and an extra 2x4 running laterally along the front to make up for this lack.

 

The reason for using a lower frame is to spread the weight out over a larger area. This is better for both the floor and the tank. even though accounting for 10 pounds per gallon is a bit of overkill, there is no sense in takeing chances, the stand alone will add another 50-80lbs as well.

 

Next is the top. The top will be constructed from 3/4" finish grade plywood, this will then be coated and leveled with thinset, allowed to cure, then a tile top made from 4" square black 'bathroom' grade flooring tile will be installed. The grout will be a sanded epoxy grout, this prevents any sort of moisture from penetrating. The edges of the stand will be finished with trim tile.

 

The sides of the stand will be made from finish grade 3/8" plywood, as will the drawers. The interior will be given a similar treatment with a bottom of 3/4" finish ply that has been urathaned until waterproof,

 

Now, the one part I need input on.

 

between the top and lower frame, there is the possibility of using a leveling plate. In it's simplest form, it's many heavy duty bolts placed between two frames, with a pair of nuts and a lockwasher on each. You level the stand once in place by raising and lowering the nuts in sequence. this is similar to how an extending support pole can be installed in a basement.

 

I'm wondering if it's even worth taking the time to install such a system, or if it would be better to simply shim in place...

 

 

Yes, this design is drastically over-engineered, but that's the point. To put something together that will do the job, period.

[neanderthalman]

Yes, this design is drastically over-engineered, but that's the point. To put something together that will do the job, period.

 

I also built a 40B stand not too long ago, and it worked out very nicely. I can give you a few tips.

 

Don't worry about the fifth post. For whether or not it will damage the floor, you have to put it in terms of psi - if you have a 2x4 post, supporting 140lb - the local floor loading is 21 psi. By comparison, a tiny 100lb chick in stilletos will be generating about 800-1600 psi per heel, depending on her stride. So, unless you don't want some honey walking around your living room for fear of her damaging your floor, then you don't need to worry about the fifth post.

 

In order to make your top completely true, you need to be able to force and hold the stand to be square in three separate planes. This means a solid back, a solid bottom (or top), and a solid side. Not everyone wants the side to be solid - i didn't, so I instead used wire and turnbuckles to pull the side square and hold it that way.

 

The issue now is that you're putting a true square cabinet on top of a likely unlevel floor. Those damn construction guys.... . I solved this by adding leveling feet under the posts. The feet have 5/16-18 threaded bolts, which are mated to 5/16 tee nuts hammered into the bottom of the posts. As for loading, well, it's not a problem. The tensile strength of a shiatty 5/16-18 grade 2 bolt is about 70-75000 psi, or about 5500lb. You've got an order-of-magnitude safety margin.

 

I'm not a fan of the tiled tops, because it's extremely difficult to make it truly flat - you're going to need to put some styrofoam down to even out the imperfections so you don't get a stress concentration from a slightly-too-high tile. It doesn't take much.

 

If you want pics, the link is in my sig.

[C-Rad]

I agree with everything Neanderthalman said. The last stand I built assumed a flat level floor. When I put water in my tank, on top of my nice square stand, it was about 1/2" deeper at one end than the other! My next stand will have leveling feet.

 

You may notice that using leveling feet on each of the 2x4 legs concentrates the weight, so that instead of 21 psi, you're up to about 114 psi (assuming 1.25" round leveling feet.) 114 psi is still nothing to worry about, and the hottie in heels comparison is still valid.

[Walking_Target]

Alrighty, leveling legs it is. I found a great product that lets you use a wood block on the floor instead of the little plastic and metal foot that some of those assemblies come with.

 

Tile is one thing i would really like to do, but I may experiment a bit before trying it on a stand

 

With bathroom tile being only $0.39 each, I have no problems making a small test rig to get the leveling right. The other option i'm presented with is making use of a granite top.... a friend of a friend has a line on some finish-grade black granite in the size i need for only $80... and that is milled perfectly level.

[neanderthalman]

The other option i'm presented with is making use of a granite top.... a friend of a friend has a line on some finish-grade black granite in the size i need for only $80... and that is milled perfectly level.

 

 

That would be sweeeeeeeet.

[bitts]

+ 1 to swweeeeeeeeeeeeetttt!!!!!!!!!!!!!!!!!!!

 

granit for what?!!!!! you could almost call it a moral imparitive.

 

love the write up so far keep it coming.