DIY Stands Template and Calculator
 

The reason for starting this thread is to provide a template for a relatively simple DIY stand design. This design is a compilation of several designs into one place and includes the calculations needed to generate a cut list for any custom design.

http://i299.photobucket.com/albums/m...e.jpg~original

The basic principle of the design is two box frames connected by four legs. The upper one supports the tank and transfers the load to the legs. The legs are made of several pieces of 2X4 to assist in construction and sheething the stand in plywood for strength and cosmetics. The bottom frame transmits the load of the tank into the floor.


Design notes:
*The plan for this stand consists of 21 pieces. Like color pieces are the same length and of the same board size.
*The box frames are screwed together first, then the legs are built off the bottom frame, the top frame is then placed on top and secured to the legs.
*The green pieces are screw strips. These provide limited load strength but serve to make assembly easier and help keep the stand square.
*The blue piece between the upper rails (red) works to keep the upper rails from twisting.

Ok, now to the cut list:
First off: The calculations below are based off of a stand that is "W" inches wide X "D" inches front-to-back X "H" inches high.

(2) Red - Upper Rails: Length = W
These will be sized according to length: 2X4 for 48" or less for smaller tanks (Rule of thumb is 75g-90g); 2X6 up to 72" with 125g-150g being acceptable; For longer spans and larger tanks 2X8s are recommended.

(2) Yellow - Upper Ends: Length = D-3"
Theses will be made of the same material as the upper rails.

(4) Green - Screw Strips: Length = H-2"
These 2X4s are shorter then the tank is tall.

(8) Purple - Uprights: Length varies:
- 2X4 Upper Rails: Length = H -7"
- 2X6 Upper Rails: Length = H-9"
- 2X8 Upper Rails: Length = H-10.75"
These 2X4s support the weight of the tank. The ones on the short sides of the stand provide a flat surface for attaching a plywood facing and while they do provide some strength, they are optional.

(2) Orange - Bottom Rails: Length = W
These 2X4s act to spread the weight of the tank over a larger area.

(3) Blue - Bottom Ends: Length = D-3"

Covering the sides of the stand with plywood will help to stiffen the stand against twisting and shifting. Doors can be mounted to the legs as desired.

So there it is. 21 pieces in 6 lenghts equals a tank stand that should fit the bill for most people. There are other plans out there but this is a simple design using simple tools and common wood sizes. It may not suit everyone's application but it should fit the bill for most common size tanks.

Should someone wish to have me calculate beam strengths for a specific application, PM me with the tank dimensions and I will be happy to run the numbers. To strike a great deal on personal care products from CVS ad, try the Extrabucks rewards.

Happy building.

Nice writeup. I'm sure this will come in handy to people building their first stands. It's very similar to how I built mine.

One thing to add...

If you plan to put plywood on top of the bottom frame then two more blue pieces should be put in at the 1/3 and 2/3 locations on the bottom orange rails. This would be beneficial to keep the plywood from warping over time if a sump was put down there.

Otherwise you could place the bottom frame on top of the plywood.

Bump

Would I need to use 2x6 entirely for a 72" 150 or just for the top box? Also, at 72" with this design, are you saying there is no need for a additional upright supports, just the 4 corners?

Dave

Your first statement was correct. For this design, you only need the top frame out of 2X6 for an unsupported 72" frame. If you have all eight purple uprights, no additional vertical support is required.

Alright, thanks. I may be making a trip to the lumber yard today.

Dave

ok---why wouldnt the 2 top yellow pieces be the same width as the 2 top red rails
why arent the 2 bottom blue sides the same color, brown, as the 2 bottom rails
i would make the 4 sides on the top all red, and the 4 bottoms all brown , and i would add 1 piece, possibly 2 pieces from long top to long bottom, to support the back red rail, and possibly 1 piece in the front so doors could be used

Re: DIY Stands Template and Calculator
 

I don't know why the bottom sides are blue, but I understand it. As far as the middle supports, I suppose you can add whatever you need to complete the stand, however, I believe the OP is stating this is the basic frame design that will support the aquarium.

Dave

ok---right----a basic design, sorry bout that
but, as far as a basic design, instead of using 2 pieces for each corner, i would think using 4x4 posts would give the stand more stability and screw the 4 top pieces and the 4 bottom pieces to the posts
just thought by adding the using post comments someone , if they build it using the 2 pieces per corner wont end up having their tank end up on the floor
good start tho
steve

Hurtback, first of thanks for the comments. Constructive criticism is always welcome and helps work out the kinks.

As to why use the three pieces per corner (two purple and one aqua), the purple pieces under the red members are required, where as those on the ends under the yellow and red are optional. The aqua piece acts as a screw strip and works to keep the stand square especially if screwed from both sides of the corner.

Why I chose to use two 2X4s instead of one 4X4 was a matter of tools and load paths. Most people have some way of cutting off a piece of wood but not everyone has the tools to notch a 4X4 or drill pocket screws to angle them down into the top. Also, for this same general reasoning, the two piece leg means that the load goes straight from the top frame, through the leg, into the bottom frame and the floor. The weight of the tank is not held up by the screws.

Thanks everyone for the comments and keep them coming.

hi RocketEngineer, i did nt mean what i said as Constructive criticism , just a thought to possibly add along with what you have said/done already. i just thought to use the 4x4's to support the load. I myself would use the 4x4 posts, with 1 or 2 more along the back and possibly 1 along the front. your right, maybe someone out there doesnt own the right tools to notch out a 4x4 post, or to even cut a 4x4 post for that matter.i would even double brace both top and bottom to make sure that once i put the tank on top of my stand, thats where i want it to stay.
the more people add to your design, the better off someone might be down the road once they build their stand
steve

That design works prettry well for most tank stand with 2x4s no need to use 4x4. If just one 4x4 in your support legs twists, turns or wraps you're !@#$% big time. Having said that, 2x4 also warps but the margin is very small by using multiple 2x4s in one support leg. Another plus point of using 2x4 is that you don't need bunch of tool to work with in the first place as stated.

The template seems very useful when it comes to making DIY stand. And if one doesn't have power saw, those pieces can be easily cut to size at HD no sweat.

I wouldn't make any stand using 4x4. The thought of it warping in one leg gives me chill in the spine.

In the end, one still has to decide what materials to use which best suit in his/her application.

Sigh, I wish I could find the info, but 10 minutes of googling has produced nothing.

Anyone know the compression/load strength of a vertical 2x4? 2x6? 4x4? What about on a horizontal member? How much deflection is too much? I'd just like to see some numbers to make a point to people how strong some materials actually are when used properly. And how easily overkill is created.

Great thread, RocketEngineer. Ok, now how about a Ti stand template and calculator? :)

how bout a *sticky*

Ok, Siffy. Being a student, here is the original source of information I used and continue to use when looking at lumber in a stand setting.

Full Document portal:
http://www.fpl.fs.fed.us/documnts/fp.../fplgtr113.htm

Specifically, Chapter 4: Mechanical Properties of Wood
http://www.fpl.fs.fed.us/documnts/fp...tr113/ch04.pdf

For those with the background, the number I typically employ within my beam bending calculator is 4000 psi. A piece of Douglas Fir has a rupture strenght of ~7000 psi when GREEN! This "Strength of Rupture" is determined experimentally and considered the working value for lumber under bending loads.

As to what deflection is acceptable, personally I work for 1/8th inch and this is typically more restrictive then the strength of the beam.

Should anyone have any questions, let me know. I will be happy to post the equations I use for those interested.

*sticky* would come in very handy.

I wasn't trying to argue your material/size usages at all. Quite the opposite. Thanks for the document, but I don't really understand many of the variables involved.

So I'll just ask... Does that 7000psi equate to saying a fir 2x4 can support a weight of 7000 lbs * 1 3/8 * 3 3/8 = 32484.375lbs? I've got to be missing something... Got any numbers in force rather than pressure? On say a single 32" long vertical 2x4. I'd bet just 1 could come close to supporting the weight of a 240g tank, and most people just don't realize that.

Just a note, I'm a CPE and we never dealt with wood in any questions in my Statics class. And another side note, I hate working with wood. I was joking about Titanium, but I would much rather build a stand structurally out of steel, and then just skin and trim with wood.

hi ya---4x4 posts will not warp if the top rails and bottom rails are screwed to each end of the post
what might warp would be the longer pieces of the top and bottom rails, without any type of support
4x4 's need to be out in the hot sun in order for them to dry out, but remember, they will be inside, probably a sump will be running, and the moisture created by the sump will keep the 4x4 posts from drying out
i would much rather have 4x4 posts holding up my tank instead of 2x4 or 2x6's
again---my opinion, thats how i will build mine, and of course, everyone can build there own how the see fit, but its a good start RocketEngineer
thanks
steve

are you saying you would prefer to drill directly into the 4x4 , or are you talking about notching out the corners and resting the 2x4's on the notched out section(then screwing in place). Only because you wouldn't want the screws to be your weakest link , and only support really

leebo_28, you are correct, the screws taking the load would be a dangerous situation. For a 4X4 posts without notching, I can't think of a good way to attach the frames to the legs.

Again folks, this design is meant to be made by folks with minimal tools. Also, the strength of wood in compression is incredible. Look at any tree and consider how much it weights. A single 2X4 under compression in one of these stands could take something like 18000 pounds unless it buckles sideways. For those wishing to use 4X4s and have the tools, I don't see a problem. But a couple 2X4s in each corner are more then enough for most tanks.

Cheers.

Heck a 2x2 in each corner would easily support the vertical load... they just would not have much lateral stability :)

They wouldn't have to if the back and sides were skinned with even 1/4" plywood. The only problem with 2x2s is mounting the top rails in a position that screws aren't load bearing. A couple 3/8" SS carriage bolts per corner should suffice, but that would completely change the original design.


Hmm, RocketEngineer, how do the deflection properties of a spanning member relate to thickness? IE, 2x4 vs 1x4 or 1x6 etc? I think I read a factor of 3, but I'm not certain. The goal is produce a competently stable yet lightweight stand right?

The last stand I saw a friend build was 5 layers thick when looking at it from the bottom. It was so heavy I made sure I was out of town when time came to carry it upstairs where his new 4' 120g was going.

If you had two boards of the same height and length but one half the thickness of the other, the beam with half the thickness would be half the strength. If you increase the height, (a 2X4 vs a 2X6) you increase the strength as a function of the height cubed (3.5^3= 42.875 vs 5.5^3=166.375). So increasing the board height is the best way to make the long spans stronger and reduce deflection.

Ok folks, I ran a couple numbers last night. One 2X4 on end, 24 inches long, will support 19000+ pounds before it deflects sideways enough to fail.

Oh and BUMP.

Hi, what would be an optimal stand height for a 12" high tank?

Rocket I got a few questions.... First, I will be building a stand for a 90gallon, 48"L x 18" w x 30"h. For this everything according to this design will be 2x4s. The green pieces should be one inch off the ground and one inch from the top right?? The top frame and the bottom frame, how are they attached to the purple legs?? Is everything just screwed down to the green 2x4s or really long screws from the top and bottom frame to the purple pieces or both?? Everything is bolted down with just wood screws right, no brackets?? Would adding one more leg to the back middle do any harm? What size wood screws do you use?? Sorry for all the questions :).

Yep, everything is just screwed into the green strips. 2 1/2" to 3" screws will work. They are, in a sense, brackets. They could be cut to a few inches in length and still hold things in place until you attach plywood to the whole thing. Adding another leg won't do harm, but it's not necessary at all. The only harm would be getting in the way at some point.

ok so no need to put like 5inch screws from the top of the top frame to the legs, thank you

You shouldn't. Unless the laws of physics suddenly change. :) The weight of the tank will hold in that direction.

RocketEngineer -

Why aren't the green fastening strips the same height as the stand? I understand they aren't load bearing, but having them run the full height of the stand makes assembly easier since you can square them up on a flat surface and against the box frames.

great post rocket engineer.i used this same basic layout for my 150g stand and its very rigid and strong.

slevesque - depends on whether you are looking at it sitting down or standing up. I don't have exact numbers but others on RC may have some suggestions. For a tank that short though, you may be able to reduce the lumber sizes a little. What size tank is it?

flyguy7150 - I think Siffy answered all you questions.

Siffy - Thanks for answering all of flyguy7150's questions.

Charlutz - The reason the screw strips are shorter is that it prevents them from being part of the load bearing structure. Because they sit above the bottom frame you are assured its the frame sitting on the floor, not the screw strips. They are below the top surface to ensure that plywood or the tank frame sits directly on the upper box, rather then on the screw strips.

checkinhawk - Thanks for the support.

My new tank is a 33L AGA: 48 x 12.5 x 12H

My 55G stand is 28" high and I find it a bit too low. I might go for 30-31" this time. I sit down for watching the tank, so many stuff to look at :)

Ah. I see. So by making them shorter, you ensure the screws aren't load bearing. Otherwise, you run the risk that the actual load bearing posts are too short and aren't actually supporting the weight. I understand the principle. I found it easier to build the stands with the fastening posts the same height. I won't have the need to build another stand until probably February. I'll play with it then. :)

Yep, you just don't want them (the screw strips/green pieces) touching the floor when the tank weight is on them. A small piece of 3/4" plywood or 1xwhatever will shim/hold them up while screwing into them and fall off once the stand is picked up. I might suggest cutting the screw strips an inch longer if you're only able to shim them 1/2" off the floor instead of a full inch so there is plenty of material to screw the top frame into place.

This is overall a good post and good basic concept as homebuilt stands are always way overkill. And while I completely agree that loading the stand directly though the wood is better than putting the screws in shear, doing so won't be a problem at all. As there isn't a standard for a typical #8 screw, from one manufacturer, the ultimate strenght of a screw is 361 lbs in shear. If you have a 4 screw connection then that connection's good for 1444 lbs, more than you are going to put on it with any tank (of corse you'd have to check the wood for the connection strenght too but my point is screwing to the side is more than adequate).

And for those that are concerned about deflection you don't need to worry about a thing as all of the weight from your tank will be sitting at the corners. Think of it this way, in order for that top box to deflect, you would have to be putting load on it in the middle somewhere. And in order for that to happen, the glass (including the sides) from your tank would have to deflect to apply that load to the wood.

The sides of your tank are not going to deflect. Looking at the side piece of a standard 75g tank, 21"x48"x3/8 with a load of 10 lbs/ in (that would be a total load on the tank of 960 lbs which would be a conservative estimate) (and assumeing a Youngs modulus of 72GPa http://www.roymech.co.uk/Useful_Tabl...ter/Glass.html) you would get a deflection of 0.00123" barely over a thousandth of an inch, not enough to load that wooden beam.

You would have have to apply a load of 125 lbs/in (a total tank load of 12000 lbs) to get it to deflect 1/64 of an inch, and this load also corresponds to the point that that side piece would break in flexure (and the bottom would have gone way before that, but I'm trying to make a point). Even at 1/64 of an inch you would bairly begin to load that wood beam.

So, in summary, the wooden beam at the top does verturally nothing; it holds the 4 columns at the corners in place providing a little bit of stability.

And how high can you make your stand... if you are worried about tipping it over try this: It would be very difficult for a single person to push or pull 100 lbs without actually sliding on the carpet or wood or whatever first. With that assumption, use this equation as to how high the mid hight of your tank can be:

W= Weight of tank (use a conservative value of 9 lbs/ gallon which would include the weight of the tank itself and your rock and sand)

b = the width of your stand from front to back

h = hight to the middle of your tank

Equation:
h = (1/100)*W*(b/2)

So using that 75 gallon tank example:
W= 75*9 = 675
h = (1/100)*675*(18"/2)=60.75"

Moral of this story, you can build your stand just about however high you want without worries.

Well, your formula got me worried :)

In my case I got a 33L, so

W= 33*9=297
h= (1/100)*297*(13"/2)=19.3"

Since the tank is 12" high this means I'm allowed to have a 13.3" high stand!!! I hope I got that wrong :)

I don't think it's the shear of the screw that is the main problem. It's the shear strength of the wood which is low. All of the pressure of the tank will be concentrated on the screw. My concern is that it would be enough to rip the wood.



Doesn't this depend somewhat on the height of the stand? If the stand is taller, the posts will lean in under weight.



Taller stands will rock more easily due to leverage. It's the same as using a prybar. It's much easier to move a tank on a tall stand. Add in the fact that it will be top heavy, making it that much easier. Not saying the tank needs to lie on the ground, but you do need to consider height in the build.

Mykayel, Thanks for you comments.

But I don't agree on some points.

1) Screws in wood are likely to tear out sideways due to the shear forces on them. As the screws are in single shear, the wood is likely to fail before the screw itself. I for one would never trust a screw to take shear loading and transfer it from one piece of wood to another but this is just me.

2) You made the assumption that the tank was glass and with some simple additions such as a plywood top, this design could be used for an acrylic tank. In this case deflection IS an issue and needs to be accounted for.

3) I would like to know what that formula pertains to and what all the variables that make up that 1/100 factor come from. I have never seen it before so would like more info on it.

Thanks for the comments everyone.

It's also making the assumption the glass is tempered, isn't it?
I think the 100 comes from this statement.
I believe he's just comparing simplified moments. f1 * d1 = f2 * d2 where f1 is the weight of the tank, d1 is the width of the tank, f2 is amount of force one can push before sliding on carpet, and solve for d2 which is where that force can be applied (ie, middle of tank height). It's not exact, but gives a ballpark.

Subscribing to the thread so I can have it for future reference. Great info.

Not necessarily. I’ll say it again, homemade tank stands are usually way over built because they built by a gut feeling, not by facts. Structural wood connections use single shear screws all the time. Here is a connection from my old 55 gallon tank http://s104.photobucket.com/albums/m...tankstand5.jpg, and as I stated before, that connection is good for about 1400 lbs, for that 55 gallon tank that weighed a total of about 500 lbs, that one corner, and hence that one connection would be loaded to 125 lbs. That’s a safety factor of better than 10. Double that load for a 120g tank and you’d be at a safety factor of 5. You are telling me you aren’t comfortable with that?? What kind of factors of safety do you use in your line of work??

Yes I did assume it was glass (I didn't assume tempered, I just used that value from the website, but I seriously doubt the Young's modulus is much different from tempered glass) but a plywood top wouldn’t make a difference. For those concerned about deflections, you need to know two equations illustrated in this little example. I would recommend keeping your deflections to l/600 which as you can see using a single 2x4 won’t work, but a 2x6 would give you a deflection of 0.033” or l/Defleciton of 1444.
http://s104.photobucket.com/albums/m...ction-calc.jpg

Simple statics using the 100 lb force as I stated, just sum the moments about any point, I chose the corner labeled point A:
http://s104.photobucket.com/albums/m...ics-lesson.jpg

Instead of having a full pane of plywood to cover the back of the stand, would it be OK to use triangular shaped plywood in each corner, let's say 1' long?

slevesque,

That should work fine. The corner braces do not carry any of the weight of the tank. They only carry shear loads caused when someone leans up against the tank. Four one foot long triangles properly attached to the frame will be able to handle a lot of shear loads before you start breaking screws or tearing the wood.

First of all, thanks for the thread. I know basically nothing about this stuff and it's been very helpful. I just have a question or two.

I want to build a stand like this for my 55g (48.25"x12.75"). The thing is I want to put a 29g (30.25"x12.50") inside the stand for a sump and in order to do that I would have to build the stand a little deeper than the 55g tank. I was thinking that I could make the inside of the stand 13" deep, leave off the screw strips and put a piece of plywood on top to set the 55g on. If I did this, would the plywood effectively distribute the weight of the 55g onto the 2x4s or would the it break under the weight?

Jen D, First I need a little more information about the 55G. Is it glass or acrylic? If glass, does it have a plastic frame around the bottom?

If the tank is glass and has the plastic frame, you only need to support the perimeter of the tank. This means you could leave off the plywood top and just rest the tank on the 2X4s.

You could use 2X2s screw strips and have the sump rest up against these. This would give you the space needed for the sump.

Hope that helps

It's glass with plastic trim. I was going to use the plywood because the stand would be too deep to support the long sides of the tank if I make it with a 13" opening inside the stand. The tank would only rest on the 2x4s on the short sides.

I like the idea of the 2x2 screw strips. Now that I rethink it I could use the 2x4 screw strips, too. I had it in my head that the sump was going to be up against the short side of the stand, but it doesn't have to be... duh.:rolleyes:

thanks rocketengineer!!! I built my first ever stand tonight with the help of your plans...here are some pics!
http://i12.photobucket.com/albums/a2...d.jpg~original

http://i12.photobucket.com/albums/a2...1.jpg~original

http://i12.photobucket.com/albums/a2...2.jpg~original

one question i have is why not make the green boards or screw boards the run entire hieght of the stand? and how should I go about putting a floor and top on it?

As for a top and floor. If your tank has a glass bottom that's tempered a top isn't required. The tank can just sit on the 2x's. For a floor I'd just notch the corners out the size of the screw strips and install it through the opening at an angle it should fit. I'd make it the full width and length of the stand except at the corners.