Cheap DIY stand for 250lbs

Discussion in 'DIY' started by magnetar68, Sep 5, 2012.

  1. magnetar68

    magnetar68 Supporting Member

    I need a cheap stand for my cuttlefish project. I need to put my 36"x16"x18" sump under astand and my 29G tank on top (~250lbs with rock). Here is what I came up with. Anyone think it own't hold? I looked at a few designs but they all seemed way over engineered. My focus is on easy and cheap, so I went with all 2x4s. The stand below can be made from seven (7) 2x4x8s (if I did my math correctly). This should be about $20 plus screws. I made the stand 48" long to give me a little extra space for my Ca Reactor. I am OK leaving the sump on the floor as it is water resistant and I don't need a top since I placed the braces so the bottom rim of the tank will always be on a 2x4 (glass tanks are supported by their edges, not the glass).

    [​IMG]

    I would build the four sides with screws and then screw the four sides together.

    [​IMG]

    [​IMG]
     
  2. iani

    iani Guest

    I'm not so sure about the design. You should make 2 frames of 2x4s to support the top and bottom. Those frames should be on top and below 2 supporting 2x4s in the corners. There should also be another 2x4 on the inside of the frames on all 4 corners. The way you have it designed you have screws holding up the front, back, and sides.
     
  3. magnetar68

    magnetar68 Supporting Member

    I don't understand what you are describing. But the thing I did not mention is that all 8 corners (top and top) will have metal angle braces, kind of like this one:http://hydrophytesblog.com/?p=214
     
  4. magnetar68

    magnetar68 Supporting Member

    Here's the pic:

    [​IMG]
     
  5. iani

    iani Guest

    Something similar to this.
    http://blog.aquanerd.com/wp-content/uploads/2010/04/Frag-Tank-Stand-1.jpg
     
  6. aqua-nut

    aqua-nut Supporting Member

    For the picture, if the glass tank sits on all four corners of the stand it is being supported by the (looks like) 4x4 posts. This is VERY strong. The brackets are overkill. They look nice, but are overkill.

    In the drawings above, if the tank does not go all the way to the vertical 2x4s the forces will be only on fasteners and in shear. This is wood and fasteners weakest orientation. You want the forces to be in compression like the picture. If you added some 2x2 material along the vertical 2x4s to support the ends of the horizontal 2x4s it would be a lot stronger.

    This is hard to describe. Are you drawing in sketchup? If you want to send me a .skp file, pm me and I'll give you my email addy.

    EDIT: Dang some people can get a link posted faster than I can think/type!! :)

    Iani posted a great example of the correct support. It's overkill but you would never have to worry about it! Notice all the horizontal parts are sitting on top of vertical parts. All forces are in compression!
     
  7. magnetar68

    magnetar68 Supporting Member

    Iani and John, thanks! I get it. OK, let me try a different configuration. Because the sump below is 36" but the tank on top is 30", I will not get the ideal configuration for the top tank. At the same time, it's only a 29G or about 250lbs. That does not seem like a lot of weight. I understand that for a 120G tank that will weigh over a 1000lbs, that all of this engineering is important, but for a 29G tank, does it really matter that much? My preference is to make the access easier to the sump than over engineer the stand. I also want to keep costs down.
     
  8. Kensington Reefer

    Kensington Reefer Supporting Member

    First...I love that CAD drawing!
    I personally, like to have my 4x4 on directly under the edge of the tank. But from your pic and the size tank you are building for, you should be fine.
    Factors to consider: the possibility (and likely hood) for horizontal movement and any torque (or twist)

    If possible, connect the stand to the wall and the floor.
     
  9. iani

    iani Guest

    So it sounds like your tank will only be supported by the screws? It will not be on top of the posts? I would be wary of putting a tank supported like that on the stand. And to be realistic, with a 29 gallon tank we are probably talking closer to 300 pounds, this is considering tank weight, sand and rocks which are typically heavier than the water it displaces.
     
  10. aqua-nut

    aqua-nut Supporting Member

  11. rygh

    rygh Supporting Member

    Yes, definitely fix those corners!

    I would put angle braces on the back instead of that cross+vertical brace you have.
    (Like you have on the front)
    It leaves more room for the sump.
    You will likely want to put pipes in that region from the back side of the tank.
    And it makes it stronger, since you only have angle braces on the front.

    You might also want angle braces on the sides, so it will not topple forward or backward.
    Although there I would suggest plywood
     
  12. magnetar68

    magnetar68 Supporting Member

    Updated design. I am planing in using 4 Simpson Strong-Ties from Home Depot to brace the 2 braces at the top ($0.79 each). Other than that, I don't think I need any more metal bracing or bracket. I am hoping to keep everything open for running pipes and access.

    [​IMG]
     
  13. rygh

    rygh Supporting Member

    You have no diagonal bracing anymore?
    That means no shear strength if pushed horizontally, say in an earthquake.
    Will it be clad in plywood? If so, not an issue. (doors do not count)

    You might rethink that front low cross beam. The one that has a 45" on it.
    While it makes doors look nice (if you have them), it makes getting the sump in and out a pain,
    plus makes it hard to clean spills.
     
  14. aqua-nut

    aqua-nut Supporting Member

    Ray,

    Looks like you could park a truck on that beast! Mark (aka, rygh) is right. Some shear wall would improve it. You could add ply ends and back panels. They don't have to cover the entire side/back. They do need to be attached to top, bottom and side. You might even want that to be able to block light from getting to the sump. If you want it really open I think you could even get away with a piece of ply with a 'window' cut into it. Kind of like the top on a acrylic tank. Any structural engineers reading this want to comment?

    Are you adding a top? Seems a shame to waste all that space next to the tank. There won't be a place for all the odds and ends to accumulate! :) I think I'd find myself dropping things in the sump without a top.

    Really, I'm not trying to make this cost more!
     
  15. Kensington Reefer

    Kensington Reefer Supporting Member

    If you go with the above drawing, attach a sheet of 3/4ply to the entire back side. This will hold for sheer, torque... I have built and designed many many stands. Not all were pretty but none have failed.
    Feel free to pm me.
     
  16. magnetar68

    magnetar68 Supporting Member

    OK, I will probably go with the design below. I appreciate the feedback; it has been very helpful.

    I did intend on a top, but wanted to show the bracing. This pic shows the top, so the bracing is as described above.

    I think the tendency among DIY hobbyist is to over engineer things. I believe this stand is structurally sound for a 29G tank even without any plywood on the sides. If we have a big earthquake and it fails, I will grant you the opportunity to say you told me so.

    [​IMG]
     
  17. denzil

    denzil Webmaster

    Yeah, DIY hobbyists generally over-engineer but that's what Civil Engineers do on a daily basis with reasonable justification in costs. If people don't know the actual forces being applied to each component of the physical support system they're building, people just tend to add extra support to be absolutely certain. Plus, it generally doesn't hurt your pockets too much for that added bit of insurance for your lack of knowing.
     
  18. rygh

    rygh Supporting Member

    The real reason to over build it:
    You are going to look at that big surface area and go : Hmmmm - I can fit a 65G on there.
    ;)
     
  19. rygh

    rygh Supporting Member

    First : Yes, for a 29G tank, it is probably overkill.
    But another failure point to consider is when some big 200 pound person
    falls on it, after looking at the pretty fish.

    You might want a diagonal brace on the ends as well, for forward/back shear forces.
    Preferably on the same leg as the side to side braces.

    Maybe you want the diagonal braces in the back, not the front. Easier access to sump.

    If on the back, you can even put them down near the floor, between legs and bottom board.
    Might seem odd, but similar effect. And keeps it open for pipes going up to tank.
     
  20. magnetar68

    magnetar68 Supporting Member

    Actually, I did think about that. I would add more support by using plywood along the sides and back if I was going to put larger tank on there.
     

Share This Page