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Re: floor loading for 135G & stand issues... (LONG)

>This post is rather pertinent to me and I am wondering
>what you used for your stand Bill? (4X4s? or 2X4s?) 
>The reason I ask is that I am in the process of
>building a stand for an eventual 200G in the basement.

My stand is made of a combination of 4x4, 2x4, and 2x6 lumber as indicated 
in my ASCII drawing here: 

(top view)
|   |   |   |

All perimeter members are 2x6, the center two braces are 2x4 mounted so that 
the top of them is even with the top of the 2x6 perimeter. 

(side view) 

||    |    ||

 - is 2x4 (the | in the middle is also a 2x4 with the wide side supporting 
the 2x6 above)
= is 2x6
|| is a 4x4 

I have the 4x4's cut so that the 2x6 is inset, something like this:
| |  |
| |  |  <- 2x6 on left
| |  |
 ---  |
|    |  <- 4x4 beam 

I used two carriage bolts to hold the 2x6 to the 4x4. The bottom of the 4x4 
is cut the same way but upside down and sits on the bottom 4x4 frame. All 
2x4 and 2x6 is oriented as you would a floor joist, with the wide side of 
the beam vertical to provide the best rigidity in the up-down direction. the 
2x6 and 2x4 frame is mitered at the corners, with the 4x4 cut as shown here: 

(top view)
      _  <- carriage bolt head
| \     2x6
|   \-------
|2x6| 4x4|
|   |----
      =  <- nut with fender washer (use the fender washer, it helps keep the
            nut from pulling through the wood) 

Underneath the 4x4 is full size, with about a 2x2's worth (around 1.5" 
square) sticking up as shown above and used to reinforce the corner. The 
bolts go through the 2x6 and the small piece of 4x4 at each corner. With 
construction like this there are no bolts carrying the load, all the weight 
of the tank is handled by the horizontal wood sections resting on top of the 
vertical wood sections. The little 2x4 braces across the top are supported 
with screws only, but they don't carry much weight so they should be OK. 

A stand built like this fairly industructible, and I did try before using it 

>the load bearing because the the basement is solid
>concrete (all 4 walls and the floor).

Mine sits on the basement concrete too. I did find out the the slab isn't as 
flat as you might think. I have some cheapo office-style carpeting down 
there that evened it out OK, but if you have a big problem you could screw a 
few *large* lag bolts into the bottom members and use them as leveling feet. 
I've done this before with good success. 

>Only thing is that I don't want is the stand to give
>way.  Also being in calif, I want to bolt the stand to
>the walls just to be safe (whats the best way to do
>this?).  I don't want to bolt it too tight because
>then it has no room to move, I think it needs to have
>a tiny bit of &#34;playing room&#34;???.  

To borrow from my industry (telecommunications), it is common practice to 
use a piece of large (5/8" or so) threaded rod to bolt between a wall member 
and the top of an equipment rack is seismically active areas. Being just 
outside Detroit Michigan we can reasonably expect solid ground to stay solid 
so I didn't worry about this :-) The seismic bracing kits I see for racks 
(our racks are usually from Homaco, which makes one of these kits) use two 
angle brackets on each end of the threaded rod, which allows the rod to be 
mounted at an angle between the rack and the wall. You'll need to bolt the 
wall anchor into your concrete using a *strong* masonry anchor. I would 
recommend the triple-point expanding anchors if you have a solid wall, or 
the expanding lead kind if you have a block wall (the triple-point needs to 
be inserted about 2" to grip, and this puts you into the hollow space in a 
block making the anchor unusable). I can get you a part number for these if 
you need one. 

I don't know if you want wiggle room or not. The telco racks are mostly 
aluminum with some made of steel, and if the equipment rattles a bit that's 
usually OK as long as the rack doesn't fall over. Bracing like I mentioned 
is going to be very solid. You could probably use some urethane sheet 
between the angle brackets to make a stiff spring if necassary. 

>footprint).  The foot print will help me when I add
>extra weight because I will be putting a 50G (possibly
>an 80 later on) as a sump underneath plus 2 X 30G as

I have plans to build a special shape tank from acrylic to put on the bottom 
level of my stand. I have a covering made of MDF to provide a level surface. 
The top of the stand is just the raw beams since the All Glass tank only 
needs support along the rim. 

>I don't think I should go any higher than 4X4s because
>the weight of the wood itself would be
>counterproductive.  The only thing that bothers me is
>that the front is left with out support (the 4X4s are
>separated by 4' in the front).  I have to do this so

I used 2x6 on the top to minimize deflection. I actually ran some 
calculations before building it to keep deflection down to under 1/16" or so 
along a 3' span (the longest unsupported horizontal span). You get more bang 
for the buck using beams like 2x6 and 2x8 than 4x4 if you are worried about 
deflection. I used a 2x4 in the center and probably could have used a 2x2 
but was concerned with possible warpage over time of such a small structure 
member. If I had the time I would have built the stand out of 2x2x1/4 
structural steel angle stock, but that's mostly because I like working with 
metal more than I like working with wood. I am also very frustrated with the 
creative interpretations many lumber mills have about dimensions and what 
constitutes a right angle. Steel mills are much better about maintaining 
tolerances of their product. 

>Like I said before, I think building the stand an
>extra 6&#34; wider than normal will give me extra
>footprint and stability (for earthquakes).  I also

Just be sure to brace it. With my stand, the vertical load is placed 
directly on the structural members, not on a table top type surface that 
needs to transfer the load to the actual supporting structure. If I built my 
stand as you described I would have used 2x6 for all members of the top 
rather than using 2x4 for the two center braces. I might have added more 
braces too. I would then have used the same 3/4" MDF on the top. The MDF is 
very flat and not prone to warpage bust it MUST be sealed from the water! 

>to access it (say 6&#34;) + plus the 4X4s on the top
>and bottom of the stand; the 200G's bottom will be
>sitting at around 32&#34; high.  Does this sound

My stand was built to allow an open top spacing of some 12-14" between the 
bottom of the MH lights that are on a moveable track suspended from the 
ceiling by steel brackets. The lighting arrangement and ceiling height 
dictated the height of the tank top, which then in turn forced the height of 
the stand to something around 28" if I remember correctly. The sump will be 
(haven't made it yet) custom built for the space, and is probably only going 
to be about 12" or so high. I mostly want to use it as a plant filter with 
horwart so I don't need anything fancy. 

I should also mention that by using 2x6 outer framing on the top and only 
2x4 for the two center braces, you can mount flourescent fixtures on the 2x4 
part and have the extra 2" (more like 1.5") around the perimeter shield them 
from view. It makes for a nice way to light the sump if you plan to grow 
anything there. My intent is to use one or two 96 watt PCF fixtures mounted 
at an angle under the top part of the stand and have them light the sump 
well enough to grow things. 

>Thanks for any advice, and your time

Sure. I probably set the list post-length record with this ;-) 


Waveform Technology
UNIX Systems Administrator