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Re: stand issues + air circulation and humidity issues




>as you would a floor joist (like you mentioned).  But
>one thing that wasn't clear to me is how many rows of
>2X6s did you put (with the wide side vertical) running
>underneath the tank? Or did you only use the 2X6 for
>the outside members?

Only the perimeter of the top is constructed of 2x6, and there is only a 
single 2x6 on each outside edge of the rectangle formed by the top 
perimeter. The bottom is only 2x4 since the floor is taking the weight 
there so deflection isn't a problem.

>what exactly is a carriage bolt? (possibly an ASCII
>drawing?) and does a place like Home-Depot carry
>these?

A carriage bolt has threads like a normal bolt, but a "rounded" head 
instead of the usual hex head. The round head has a square section beneath 
it that bites into the wood when you tighten it and then holds as you 
continue tightening it. The result is that it looks something like a rivet 
from the outside and doesn't protrude out of the wood the way a normal bolt 
would. I like to use them in wood where I want a finished appearance. Home 
depot DOES carry them (I got mine there). You have two choices though: 
shiny chrome-looking, and dull gray. You want the dull gray hardware since 
that is the galvanized stuff and will hold up much better than the shiny 
cadmium-plated stuff.

>I think the carpet trick should work for me, but just
>in case, how "large" of a bolt are we talking here?
>(diameter) and how many of these "feet" do you think I
>would need to employ for a large tank such as this?

Maybe 7/16" or 1/2". Something large enough that it won't rip through the 
wood with the many hundreds of pounds it will be carrying. The fewer you 
use the easier the leveling will be, but the more stressed the wood 
structure will be. You will probably need at least six, ALWAYS one on each 
corner, and then 1-2 along each of long spans as well.


>Do you think this method would really work for such a
>large weight?  It does concentrate the load in one
>area (creating high pressure).  Do you think its a
>high enough load to do damage to the concrete? (I
>doubt that...)  How far apart would you recommend I
>space these "feet" if I need to use them? (assuming I
>go with a 9' stand)

I've used this up to several hundred pounds back when I was rigging stage 
lighting equipment. I haven't used it on a tank yet, but I'm certain it 
will work as long as the materials are scaled up to the sizes needed for 
the weights involved. I'd probably want one every 3' or so around the 
structure. It will take some effort to get them all leveled, but it should 
work for you.

>how long would the bolt have to be since it needs to
>go into the wall too!

The wall anchor holds an angle bracket, then a second angle bracket bolts 
to the first and to the threaded rod section. The idea is that the joint 
between the two angle brackets can act as a hinge and allow some flexing. 
With the lead anchors I mentioned you can use a long bolt since the extra 
length will just go all the way through the anchor and into the open space 
within the blocks.

>I do have block walls and so I can't use the
>triple-point expanding anchors (by the way, is this
>the variety thats used to bolt foundations too?)
>Since it is a block wall, what type of expanding leads
>would I need (how long?)

The expanding lead anchors are a conical wedge sunk into a lead cylinder. 
Home depot does not always carry them but many hardware stores do. If you 
can't find them that way, just about every electrical supply house will 
have them since electricians can not live without them :-) The only problem 
with the lead type anchors is that you need a special tool to properly set 
them, and the tool (made by Greenlee, maybe others), is about $50. With it 
you just screw the anchor onto the tool, put the anchor into the hole with 
the tool on top, and then bang on the tool with a hammer until the anchor 
feels solid. I've occasionally set the anchors by using a regular bolt, a 
washer, and a short (1/4" or so) of thick wall pipe between the bolt and 
the anchor. You can then insert the assembly into the wall until the washer 
is against the wall and tighten the bolt until the anchor sets. As you 
tighten the bold (or bang the tool), either the bolt pulls the wedge into 
the lead expanding the lead against the block, or the tool pushes the lead 
around the wedge and into the block. Either way works but the tool is lots 
easier. My company uses these anchors to mount equipment racks onto walls 
and they support hundreds of pounds like that.


>I like this idea.  Does Home-Depot carry the urethane
>sheets?

Not that I'm aware of. http://www.usplastics.com does. The sheet is 
expensive, you are better off buying a piece of the rod and cutting discs 
of it.

>sorry, but that flew right over my head.  What does
>MDF stand for?

MDF = Medium Density Fiberboard. It is basically particle board, but made 
with a finer particulate. It tends to be dimensionally stable over time and 
it is fairly easy to work with. A lot of commercial enclosed wooden tank 
stands are made entirely from MDF sheet.

>Do I need to worry about warpage with the 2X6, 2X4, or
>4X4s?

Probably not. 4x4s tend to be stable. If you brace the 2x6 and 2x4 every 2 
or 3 feet the way you probably need to support your tank you won't have any 
problems. Just make sure to select good boards to start with.

>YES!  I was thinking the same thing and I alluded to
>it in the beginning of the email that I am writing.
>How many center braces would you recommend I put in?
>(assuming the tank is 2.5' wide) and how much spacing
>in between the braces?

My stand uses braces on 2 foot centers. This is mainly because that's where 
All Glass has braces in their tank's plastic framing. One brace in the 
center would probably have been fine. You probably need a brace every 3' or 
so if you intend the 1.5" wide beams to line up well with the edge of the 
tank all the way, maybe 2' to be on the safe side. I like to over build a 
bit and not have to worry about bad things happening in the future.

>where? can you give me some suggestions?

For an 8' wide tank you have 2' more length than I do, so you'd want one 
more brace than I used if you follow my design. That means 3 braces in the 
middle of the top spaces every 2 feet. For such a long span I'd definitely 
put one center vertical support on the front and the back too. So many 
commercial stands -- especially the lightweight metal ones -- have 
insufficient bracing along the longest spans and I see them supporting 
tanks only on the extreme left and right edges which is asking for trouble.

>I really wish I knew what this MDF stuff was! ;-]  And
>speaking of sealing, warpage, and water; Did you stain
>your wood?  Are there stains that are water
>"resistant" (or "proof")  What about paint (I would
>use paint if it could keep the moisture out better
>than a stain).  Also, is lamination a practical
>choice? (like the kitchen counter-top kind)  If

I used a polyurethane sealer. A few coats of that and you will essentially 
be encapsulating your stand in plastic. Paint *everything*. I'd probably 
paint the wood and then assemble everything to allow the possibility of 
dismantling the bolts in the future, but otherwise paint everything. I 
wouldn't bother with laminates since you probably won't be able to seal 
them around the edges and you'll end up trapping water inside the structure 
which is even worse than no protection at all.

>using to give a boost to my foot print area).  Simply
>because I will be sticking my hands in and out of the
>tank constantly (don't we all!) and even if you
>couldn't destroy your stand Bill, H2O can do it
>effortlessly!

If you paint everything with the polyurethane and then put a laminate on 
you should be fine. You could stain the wood and then apply the 
polyurethane (although the polyurethanes I've seen all tint things a bit 
yellow so keep that in mind) and maybe make the stand look nice enough you 
wouldn't need the laminate. If you really want to be water proof there is a 
company called Fibergrate that makes fiberglass structural extrusions for 
use in marinas and water treatment plants. Strong and completely rust free! 
Very expensive though. I would have spent some $800 to build my stand that way.

>then I might have to install the lights in between the
>braces.  For that, I could put in a couple of 2X2

If you use PCF lighting you can fit enough light in a small enough space 
that you have a lot of options for concealed lighting.

 >since you mentioned that you did your project in a
>basement as well, how did you take care of the high
>humidity that the tank causes?  I mean basements are
>humid enough as it is!  Obviously, I will have to try

I haven't done anything but I really should. I don't have everything fully 
finished yet though so I guess that's my excuse ;-) I did see a heat 
exchanger system that can exhaust the humid air and conserve the heat which 
is good for us in the frozen north (34F outside right now here, no more 
summer for us).

 >"circulation" system which would basically consist of
>two computer fans, two DC power supplies, and some PCV
>pipes like so:

You could use AC fans and leave out the power supplies if you want.

         -Bill
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Waveform Technology
UNIX Systems Administrator