Multi tank stand idea. Thoughts?

[hose91]

Fair point. My stand sits on a concrete slab in the garage, so I didn't consider that. Even so, the subfloor will spread the point loads out to the joists anyhow, so unless you're worried about a dent in hardwood floors, that's not a terribly large concern. When locating my 75G on the second floor, I found this very good article by a moderator over at cichlid-forums who is an experienced structural engineer. (I'm a civil engineer and work with lots of structural guys which has given me an appreciation for what they do). It's worth a read...http://www.cichlid-forum.com/articles/aquarium_weight.php

The section following Myth #9 where he defines the types of stress and talks about what happens when you put the aquarium on the floor is where he talks about the pressure from stand legs on the floor.

 

[justin case]

What angle does that pressure propagate at? I know clamping force spreads at a 45° angle. Or close. And I'd think vertical load pressure would follow along the same lines. So if the foot were to land directly between joists the load would never come close to the joists. Even using 2 inches of subfloor which is way out of the realm of reality. I'm trying to remember what the last house I built was engineered for as far as the dead load and live load. Seems like 10 lbs a sq ft dead and 50 live? Its been a few years but those numbers seem right.

 

[hose91]

I'm not sure that clamping force and load propagation follow the same rules. If you put a 2x4 across 2 sawhorses 6 feet apart, and then put a 40 pound 5 Gallon bucket of water in the middle, the saw horses definitely pick up the load, and they'd be far outside a 45 degree angle cone from the bucket. As you get farther from the supports, the vertical load changes from a shear force to more bending moment. And the deflection in a bending moment is proportional to the stiffness of the material. So a 3/4 inch plywood subfloor nailed to the joists would transfer some portion of a point load to the joists on either side while also probably deflecting some due to the bending stress.

All of which is sort of beside the point for the OP. I see the point of the extra 2x4's, and they also serve as screw strips to give the other pieces something to screw into. You can go either way. On the plus side, it's great to be thinking about this sort of stuff.

We're working with significant loads for furniture, and you definitely want to be somewhat careful about where you put 80 (or more) gallons of water in your house, and you also surely want to be sure that in the stand itself, you are supporting the load with the wood to the ground, not on wood screws. Lots of ways to do that, for sure. I still owe some pictures of my stand. I'll work on that tomorrow.

 

[Madness]

I know very well how to build. And i still think having more weight above less weight us a bad idea. Unless the base is a good bit,like 1.5×,bigger than the upper levels. Or if its well secured to a wall. Say you have 4 soup cans. One is full and the rest are empty. Now what happens if you stack them one on top of the other with the full one at the top? It may be fine for a while but sooner or later some one will slam the door to hard and down it all comes.

This makes absolutely no sense. The heavier upper tank is not resting on the (empty) tank under it. Lets put it this way, someone builds a tank stand that is 8' high, strong enough to support the 150. After said tank is up and running, the individual decides to add a tank below this one and they build another level , and so on.

Like i said above, if the stand is built with each level being supported from the floor with the appropriate supports then there is absolutely nothing to worry about

 

[hose91]

I don't think he's referring to the strength of the stand for supporting. He's referring to the stability. All is well as long as the weight is coming straight down through the stand. If you have a weight that is higher off the ground, it's center of gravity is also higher, and any time a horizontal displacement is applied, the moment arm is bigger because of the higher stand, and it takes less horiz force to tip over the stand. Moot point if you anchor it to a wall. But still accurate. What's harder to push over, a 75G on a stand 24" off the ground, or one that is on a stand 60" off the ground, all else being equal? Again, you're both right, just to different aspects of tank stands, and for the stability aspect, it is generally intuitive to put the larger tank lower to the ground to lower the center of gravity. Not required, but if you decide to raise the center of gravity, then you should be aware that you have less stability and should maybe address that (anchor to a wall, make the feet of the stand much wider, etc).

 

[justin case]

Exactly. As long as everything is built plumb and level all is well. But if you're a quarter bubble out of plumb it's not going to take much for the whole thing to come tumbling down. I know very well how strong framing lumber is. And that's not at all what I was talk about. Think leaning tower of pizza. Or better yet a tree being felled. It stands til it reaches a certain point where it just don't stand no more. That what I'm worried about here. Not a vertical collapse. But like hose said nothing to worry about if secured well to a few wall studs.

 

[justin case]

I mean,no disrespect to the OP or any one else but for all I know they just got a saw and a screw fun for Xmas and suddenly they think they know how to build some thing. Just wanted to cover as many basses as possible.

 

[hose91]

Not to beat a dead thread, but I did snap some photos of my stand last weekend.

Full shot. Garage door was open behind me, so got some glare.


This what the lap joint looks like for where the 60" front and back supports join the vertical supports. The short 2x4 section you see behind the power strip and under the plywood is glued and screwed to the vertical supports. That joint bears some load, which isn't ideal. The plywood shelve are screwed down as well, to give it some stiffness. There are 2 small strips of plywood (60" x 8") across the back to prevent racking.

Here's the front on that same side.

Overall it's a solid rack. I would probably do it all over again pretty similarly. I might do a better job of notching the 2x4s for the lap joint. I used a mitre saw to make a bunch of cuts then chiseled it out. I think a jig saw would probably work better. You can see it's not a super tight fit, but it's good enough for my garage and it transfers the load to the ground just fine. When I put the 100G on it, I added the lower middle vertical support to keep the lower cross members from deflecting too much. Otherwise, I'm pretty happy and it gives me lots of wood space to screw accessories to like power strips, tool holders and hanging baskets. Good luck with your build plans!!

 

[GraphicGr8s]

Not to beat a dead thread, but I did snap some photos of my stand last weekend. View attachment 2526

Full shot. Garage door was open behind me, so got some glare.

View attachment 2528
This what the lap joint looks like for where the 60" front and back supports join the vertical supports. The short 2x4 section you see behind the power strip and under the plywood is glued and screwed to the vertical supports. That joint bears some load, which isn't ideal. The plywood shelve are screwed down as well, to give it some stiffness. There are 2 small strips of plywood (60" x 8") across the back to prevent racking.
View attachment 2527
Here's the front on that same side.

Overall it's a solid rack. I would probably do it all over again pretty similarly. I might do a better job of notching the 2x4s for the lap joint. I used a mitre saw to make a bunch of cuts then chiseled it out. I think a jig saw would probably work better. You can see it's not a super tight fit, but it's good enough for my garage and it transfers the load to the ground just fine. When I put the 100G on it, I added the lower middle vertical support to keep the lower cross members from deflecting too much. Otherwise, I'm pretty happy and it gives me lots of wood space to screw accessories to like power strips, tool holders and hanging baskets. Good luck with your build plans!!

That's also about how I built my racks. I didn't use plywood though. Since these are in a fish house I knew I was screwing them to the wall in case my then 4 year old decided they were a ladder.
The idea is wood to wood to floor. I used 2 x 3 on most of the racks and a couple are 2 x 4 just because I had them.

Here's a link to a thread I have on another forum with pics of the stands:

http://www.plantedtank.net/forums/12-tank-journals/787753-some-pictures-fish-house.html
There's one rack that has over 156 gallons on it now.

The lap joints don't have to be a real snug fit. What is needed though is for the bottoms of all the laps to be at the same height.

 

[xicaque]

Instead of using that many blocks and wood, have you thought about going to Costco and getting one of those metal racks? I have my 110 acrylic and it fits perfect.

 

[krislhull]

Not to beat a dead thread, but I did snap some photos of my stand last weekend. View attachment 2526

Full shot. Garage door was open behind me, so got some glare.

View attachment 2528
This what the lap joint looks like for where the 60" front and back supports join the vertical supports. The short 2x4 section you see behind the power strip and under the plywood is glued and screwed to the vertical supports. That joint bears some load, which isn't ideal. The plywood shelve are screwed down as well, to give it some stiffness. There are 2 small strips of plywood (60" x 8") across the back to prevent racking.
View attachment 2527
Here's the front on that same side.

Overall it's a solid rack. I would probably do it all over again pretty similarly. I might do a better job of notching the 2x4s for the lap joint. I used a mitre saw to make a bunch of cuts then chiseled it out. I think a jig saw would probably work better. You can see it's not a super tight fit, but it's good enough for my garage and it transfers the load to the ground just fine. When I put the 100G on it, I added the lower middle vertical support to keep the lower cross members from deflecting too much. Otherwise, I'm pretty happy and it gives me lots of wood space to screw accessories to like power strips, tool holders and hanging baskets. Good luck with your build plans!!

That is pretty much what I had in mind, only just not as wide! I think what I have planed will work just fine!

 

[hose91]

Alright, good luck!! It was fun to plan and build, though clearly my carpenter/framing skills could use some work. Looking forward to seeing pictures of your new stand!