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Zacktosterone
07/31/2017, 08:46 AM
i usually just use rocketengineer's plans for stand design but i need a little help on this one.

I have a 72x30x30 reef tank with 3/4" glass. usually the protocol would be to use a 2x8 as the joist (per say) to bare the weight.... the stand is going to be 30" tall the problem is that if I use his design then it's only going to leave me with an accessible space of 20" which is kind of impossible to do any work in.

i'm wondering if sistering 2 2x4 together and having a center support would in the stand would allow for a stronger build with maximal accessibility. thoughts??

mcgyvr
07/31/2017, 09:11 AM
Yes...
No need for 2x8s in any tank stand really..
Sister those 2x4's and enjoy..

Zacktosterone
07/31/2017, 09:55 AM
Yes...
No need for 2x8s in any tank stand really..
Sister those 2x4's and enjoy..


obviously you're sure about that or you wouldn't answer but please elaborate on how strong a sistered 2x4 is vs a 2x8.

what would a stand plan look like if I sister the stand. i need to get an idea on verticle supports

prsnlty
07/31/2017, 10:27 AM
We built our stand for the 180 peninsula with 2x4 and 2x8 for the top joists using his basic plan but tweaked a bit. Our stand is 34" high and just slightly oversized with plenty of headroom underneath. I'm glad we went with the 2x8 because it also gave extra room for mounting stuff like a 24" UV up and out of the way.

The 1st pic is before we added floor joists and floor. 2nd pic before it was skinned. 3rd pic is completed along with a pull out hidden drawer (near the wall- you can see where I have it cracked open).https://uploads.tapatalk-cdn.com/20170731/0e7c08b43b6c2dcb91949b28bb49b014.jpghttps://uploads.tapatalk-cdn.com/20170731/d50a0b519a6acaebc2ef0b43ac3693a2.jpghttps://uploads.tapatalk-cdn.com/20170731/9ce918b0f30f57396241dba1a3114d15.jpg

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Zacktosterone
07/31/2017, 11:34 AM
Nice stand. But the purpose of this thread is to build a stand without 2x8s my ceilings are low and my tank is 30" high. So my opening is too narrow

prsnlty
07/31/2017, 11:37 AM
Nice stand. But the purpose of this thread is to build a stand without 2x8s my ceilings are low and my tank is 30" high. So my opening is too narrowAhhh, I see. I'm sorry, I guess I misunderstood.

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mcgyvr
07/31/2017, 11:42 AM
obviously you're sure about that or you wouldn't answer but please elaborate on how strong a sistered 2x4 is vs a 2x8.


They are basically identical to each other..

Is the tank rimmed on the bottom?

Zacktosterone
07/31/2017, 11:47 AM
They are basically identical to each other..

Is the tank rimmed on the bottom?

No it needs foam

mcgyvr
07/31/2017, 11:48 AM
No it needs foam

Ok..
Are you planning on having 1 long 72" span with no vertical supports the whole way?

Zacktosterone
07/31/2017, 11:52 AM
Ok..
Are you planning on having 1 long 72" span with no vertical supports the whole way?

I'm going to have a single vertical support in the front and 2 in the back (because of the center overflow) my problem is that my sump is 60x26x15. So the width is now a factor

mcgyvr
07/31/2017, 12:00 PM
I'm going to have a single vertical support in the front and 2 in the back (because of the center overflow) my problem is that my sump is 60x26x15. So the width is now a factor

possibility of sump being inserted from one end?

Stand skinned with plywood? (1/2" min?)

Zacktosterone
07/31/2017, 12:07 PM
possibility of sump being inserted from one end?

Stand skinned with plywood? (1/2" min?)

I'm going to skin only the sides with 3/4"
Stand going on the side isn't a problem

mcgyvr
07/31/2017, 12:16 PM
Here.. (see attached)

Front vertical is installed after sump is put into place..

Zacktosterone
07/31/2017, 12:30 PM
Here.. (see attached)

Front vertical is installed after sump is put into place..

That inner sistered 2x4 doesn't need to be supported vertically? (of course it will be glued and screwed to death to the supported 2x4)

mcgyvr
07/31/2017, 12:37 PM
That inner sistered 2x4 doesn't need to be supported vertically? (of course it will be glued and screwed to death to the supported 2x4)

Nope.. (well... it technically would be better) but its sufficient as is shown provided its glued/screwed to the other... (to death is not necessary)..

But doing it like that is the only way to fit your sump in there.. That gives 27" front to back and you need 26" right..

And the 3/4" skinning of the sides will help tremendously with potential front/back racking..

Zacktosterone
07/31/2017, 12:41 PM
Double post

Zacktosterone
07/31/2017, 12:43 PM
Nope.. (well... it technically would be better) but its sufficient as is shown provided its glued/screwed to the other... (to death is not necessary)..

But doing it like that is the only way to fit your sump in there.. That gives 27" front to back and you need 26" right..

And the 3/4" skinning of the sides will help tremendously with potential front/back racking..

Ok then. Last question. What Would need to be done if I didn't want a front vertical support

Also the stand will be 72.5 by 30.5

mcgyvr
07/31/2017, 01:03 PM
Ok then. Last question. What Would need to be done if I didn't want a front vertical support


What is the allowable deflection for the center of tank?

I'm personally not sure how much deflection is allowed in a rimless tank with no bottom trim..
I have a rimless deep blue tank but its trimmed on the bottom so I treated it as a normal tank and supported at the 4 corners and didn't concern myself with center deflection..

removing the center certainly will allow far more deflection there..

mcgyvr
07/31/2017, 01:08 PM
With center..
This was a very quick analysis and I don't have the materials setup properly for wood but I'm getting .1" of deflection with no support and far..far less with center support..

Zacktosterone
07/31/2017, 01:42 PM
With center..
This was a very quick analysis and I don't have the materials setup properly for wood but I'm getting .1" of deflection with no support and far..far less with center support..

So to give you some more info

I'm going to put 3/4" plywood on the top as well

Also the tank has trim on the bottom but it's decorative, it does not support the bottom pane, and secondly the tank is erobraced on the top and has an inner brace on the bottom perimeter

Let's play with more ideas.
Using 2x6 instead. Raising that stand by 2" and creating a bucket in the bottom for the sump to sit in if the horizontal supports on the bottom are screwed in laying down with a 3/4" ply bottom. So the sump is sitting a little lower than the 2x4 horizontal runs. Then I will have more clearence

oreo57
07/31/2017, 01:45 PM
A doubled-24 is only half as strong in flexure as a single-26. The bending moment of inertia “I” of a rectangular section is proportional to the cube of the section’s height. I = 1/12 [b*h^3] where b is the width and h is the height. Every little bit of additional section height counts WAY more than adding (a whole bunch of) width.


If you consider a 2x4 (of Eastern White Pine, straight grained, no knots) as being a shelf that is 1.5" wide and 3.5" thick (in other words using it on edge), and using 4' spans, and putting a load of 500 lbs on it at the center, the sag would total .1". That's actually better than I thought it would be. In actuality, that is a worst-case scenario. You would not be putting a 500 lb point load on the center of the span, but would spread it out a bit. A uniform distribution of 500 lbs across the span yields .05" sag, so your real load would be somewhere between the uniform and center scenarios. Sagulator also notes that these are initial deflections. Beams and shelves will sag an additional 50% over time. It says a target allowable sag should be .02" per foot. The measures I provided here are totals, so divide those by 4 to get per foot measures.

If you use something a bit more sturdy than pine, say white ash, the sag is lower by about 20%.

I'm not exactly sure of your design. You say the bench will be "suspended". I'll make an assumption here in that you would most likely use 2 2x4s, tied together in some type of frame under the seat. The sag drops to .05" (center load), and .03" (uniform load). I assume you will use something on top of the 2x4 frame as a seat which will actually help strengthen the assembly and the sag will drop a bit more. Sagulator says this construction could support over 1000 lbs uniform load.

Bottom line is that you should be able to build a very sturdy structure using just 2x4s over 4' spans.

For comparison, if you use a 6.5' span, the total sag with 2 pine 2x4s on edge under the seat, the sag computes to .22" (~1/4") over the span, .033" per foot. That's a little higher than sagulator's recommendations of .02" per foot. So, if you use 2x6s (1.5"x5.5") instead of 2x4s, your total sag would be .06" or .009" per foot (and support over 2000 lbs uniform load). You could actually rip those 2x6s down some if you want to. 2 1.5"x4.5" boards would get you sag calculations of .10" total and .016" per foot ( supporting about 1200 lbs uniform load).

And lastly, if you use 2 2x6s on 4' spans, your sag will be .01" total, .003" per foot with 500lbs center loaded. This construction, according to Sagulator, could support ~6000lbs uniformly load... A very, very sturdy bench indeed!

Lsufan
07/31/2017, 07:55 PM
I almost always agree with mcgyver but the only way I would go without a center support is to use a 2 by 8 top frame. Being that isn't possible I would sister the 2 by 4 like y'all are discussing but I would use a center support. Doubling up a 2 by 4 isn't the same as a 2 by 8.

As far as being able to slide the sump in from the end. I would only set it up with only a single 2 by 4 for the vertical support on the corners & once u install the sump add the other 2 by 4 & screw them from the inside of the stand so u can get to the screws if u ever have to remove the sump. Doing it that way u will have 27" to slide the sump in, once u double up the support u would only have 24" so the sump wouldn't fit. The only downside is u won't be able to glue the 2 by 4 supports together because u would have a hard time getting the sump out if u ever need to. I would just use more screws then u normally would & screw them on a small angle to where they don't go straight in.

Something else u can consider, I take it as u said u aren't skinning the front of the stand. If u don't want a center support & being u have a 60" sump, u can put a support on each side of the sump. So then u would only have a 60" span without a support. In that scenario I wouldn't hesitate to use a double 2 by 6 as the top frame because u would essentially only have a 60" span

Zacktosterone
07/31/2017, 07:57 PM
I think the solution is to just go with a metal stand

bblumberg
08/01/2017, 03:45 PM
I think the solution is to just go with a metal stand

^this is the best option for maximizing space inside the stand.

McPuff
08/02/2017, 04:27 AM
https://uploads.tapatalk-cdn.com/20170731/9ce918b0f30f57396241dba1a3114d15.jpg

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I'd love to see a front view full tank shot of this one!

prsnlty
08/02/2017, 11:29 AM
I'd love to see a front view full tank shot of this one!The stand or the tank? lol

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prsnlty
08/02/2017, 11:36 AM
I'd love to see a front view full tank shot of this one!The other side with the stand... we have an enormous sectional that butts up to it.
https://uploads.tapatalk-cdn.com/20170802/75590ab472778aaa89e8a4e86e6d47da.jpg

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JohnZena
08/03/2017, 06:28 PM
i usually just use rocketengineer's plans for stand design but i need a little help on this one.

I have a 72x30x30 reef tank with 3/4" glass. usually the protocol would be to use a 2x8 as the joist (per say) to bare the weight.... the stand is going to be 30" tall the problem is that if I use his design then it's only going to leave me with an accessible space of 20" which is kind of impossible to do any work in.

i'm wondering if sistering 2 2x4 together and having a center support would in the stand would allow for a stronger build with maximal accessibility. thoughts??I would take it one step further. Double 2X4s sandwiched together with 3/4" plywood. You in essence then create an I-beam. Googlecthe strength of this versus a 2X8. The numbers will be astonishing

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Zacktosterone
08/03/2017, 06:36 PM
I would take it one step further. Double 2X4s sandwiched together with 3/4" plywood. You in essence then create an I-beam. Googlecthe strength of this versus a 2X8. The numbers will be astonishing

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Is this a thing?

JohnZena
08/03/2017, 07:07 PM
Is this a thing?Indeed. Google wooden I-beams. Done right they can be as strong as steel.

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ca1ore
08/04/2017, 04:40 PM
I would take it one step further. Double 2X4s sandwiched together with 3/4" plywood. You in essence then create an I-beam. Googlecthe strength of this versus a 2X8. The numbers will be astonishing.

Maybe I am not clear on what you are proposing, but sandwiching a 3 1/2" strip of ply between two 2x4's is not the same as a wooden I-beam. While I agree that this kind of engineered lumber can be very strong, the lack of depth (only 3 1/2") would I think be problematic.

On my big tanks, I use 2 thicknesses of 3/4" ply laminated together for the long horizontal supports, but I go 8" deep (with a center support) which fails to address the problem the OP is trying to solve.

Zacktosterone
08/08/2017, 03:23 PM
so if a metal stand isn't an option.. can i make the stand out of only 2x4s with 4 vertical supports in the back and 3 in the front? this way i can still see everything and access the sump. If I can do it without plywood being screwed on the sides then i can slide the sump in through the sides. thoughts?

JohnZena
08/08/2017, 03:34 PM
so if a metal stand isn't an option.. can i make the stand out of only 2x4s with 4 vertical supports in the back and 3 in the front? this way i can still see everything and access the sump. If I can do it without plywood being screwed on the sides then i can slide the sump in through the sides. thoughts?You have options. In short yes, you can use 2x4s. I would eliminate the center front myself. What size tank? Liverock and how many pounds?

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Zacktosterone
08/08/2017, 03:43 PM
You have options. In short yes, you can use 2x4s. I would eliminate the center front myself. What size tank? Liverock and how many pounds?

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the tank is a 240 gallon 72x30x30.

JohnZena
08/08/2017, 03:50 PM
Have you considered making the stand 4 or 5 inches taller. Then you could use the 2x8 and still have your sump space. All you need do is change your vertical measurements by 4 or 5 inches. All other measurements remain the same. Its your cabinet. Its the height you choose. I am making mine higher than normal for space.

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Zacktosterone
08/09/2017, 10:55 AM
Have you considered making the stand 4 or 5 inches taller. Then you could use the 2x8 and still have your sump space. All you need do is change your vertical measurements by 4 or 5 inches. All other measurements remain the same. Its your cabinet. Its the height you choose. I am making mine higher than normal for space.

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Not enough ceiling room

Rx79394
08/11/2017, 03:06 AM
Not enough ceiling room

Easy solution... raise the ceiling.

Zacktosterone
08/11/2017, 07:06 AM
Easy solution... raise the ceiling.

No problem. I'll go get the jacks and start raising the house so I can install some concrete spacers in the basement

Zacktosterone
08/11/2017, 07:07 AM
Easy solution... raise the ceiling.

No problem. I'll go get the jacks and start raising the house so I can install some concrete spacers in the basement pereimeter. Or maybe I should start planning down the studs