Wood stand possible for 300g... no center brace?

[RocketEngineer]

@RocketEngineer thoughts?

Yeah, don’t need 2X6s for the uprights but will certainly do the job.

 

[whitelightning77]

Yeah, don’t need 2X6s for the uprights but will certainly do the job.

Had more 2x6s on hand than 2x4s for some reason, so figured I'd use them up.

 

[RocketEngineer]

Had more 2x6s on hand than 2x4s for some reason, so figured I'd use them up.

Ah! That’s fair. No need to go buy stuff when you already have what would work. Carry on.

 

[Rit6942]

48" sump would still fit with a "center" brace that is offset from center of the 84" span.
The issue with wood is not necessarily strength, but more about warp/deflection in the center.
Having a rim helps, since the primary support comes from either end of the tank rim, but some center support is needed for security on an 84" tank.

Offhand, I would recommend using 2x6's for most of the frame except for 2x8's or 2x10's for the 84" span and use a "center" support set for 50"-54" clearance for adding/removing the sump.
This design would be better than no center brace, as it would still provide significant deflection prevention at the center:

P.S. I would certainly recommend a center brace (probably truly centered) on the back span.

Im going to be building a stand also for a 240g(8x2x2) tank. It also needs to be braceless in front. Ill be using 2x10s for the top span. The rear of tank will have a center support(multiple 2x6 uprights), but the front needs to go without a brace......so i was gonna do a 2x8 sandwiched to a 2x10 in front........glue em and screw em together.......then the top will have 3/4" plywood glued and screwed to the 2x10s. The uprights(legs) in the front will also be 2x10s...........so the effective unbraced front opening will be about 6 feet give or take a few inches. Its an acrylic tank.........so hoping thats enough to negate any deflection..........your thoughts?

 

[Rit6942]

Yeah, don’t need 2X6s for the uprights but will certainly do the job.

Hey check out my post on previous page.......basically doing your design for a 240g 8x2x2...........needs to be braceless in front so doing 2x10s with an added 2x6 glued and screwed to front 2x10........effective opening of span will be 6-6.5 feet. Thoughts?

 

[vetteguy53081]

Like the title states, it's it possible? I might be getting a 84x36x24 low iron tank this weekend. Wondering if a wood stand with no center brace is possible?

Very risky with No center. The Only way I would consider is having a Plywood Top on the stand and at Least a brace in front or back center allowing you to place a sump underneath without interference.
My stand on a 400g is wood and has plywood top and Brace every 24"

 

[workhz]

What’s a plywood top going to do for deflection?

 

[Rit6942]

What’s a plywood top going to do for deflection?

My assumption is when its glued and screwed into the top frame it will act as a partial "I" beam. Just another layer to add strength........

 

[timry2]

I have 300 gallon 96x30x24. I build my stand with 2x4’s and 4x4’s. I topped it with 1” plywood and sealed it with an oil based paint. My sump is a 75 gallon 48”long and i can pull it out with no problem. I have center bracing and the 2x4’s are on their side resting on top of the 4x4’s no sagging or warping

 

[timry2]

What’s a plywood top going to do for deflection?

The plywood will prevent sagging and warping. 3/4 will work but i overkilled with 1”.

 

[Lost in the Sauce]

The look, but mainly because I have an 80 gal sump which is 48x24. So I want to make sure I can remove it if need be. It's a rimmed tank.

That is not a reason to build a stand without a center support imo.

That is a reason to build a stand with a removable center support that is tightly fit or offset the support to allow the addition of the sump.

 

[Sisterlimonpot]

I'm late to the party, but I built a stand with no vertical supports on the back side of my 96" long 300g so that I can access all the equipment below.

I ended up using a glue lam, and I believe the safe tolerance for deflection was 1/8". I opted for 1/16" to be on the safe side.

If I recall correctly, wgile at the lumber store, I was able to speak with the engineers of the place that fabricates the glue lams, I told them the weight and length and the desired deflection and they recommended the right piece of lumber for the job.

Here's the section of my build thread depicting the stand build.

Post in thread 'My rendition of 300' https://www.reef2reef.com/threads/my-rendition-of-300.550019/post-5661495

This tank has been up and running for almost 5 years now without any issue. And I love the ability to gain access to everything under the tank.

Jimmy

 

[Lost in the Sauce]

What’s a plywood top going to do for deflection?

Length wise, nothing. It'll triangulate the rectangle but add essentially nothing for vertical support, deflection, warping.

 

[kenchilada]

Ask about building a stand on this site and suddenly everyone is an engineer, but there’s only a few people I’d listen to and one of them is RocketEngineer. Don’t overthink it.

 

[jsker]

Not one 2x4 and a granite top. The cabinet is made with Honduran mahogany, fiddle back maple and cabinet plywood for the casework. I do not like a sump under the tank, for easier maintenance. forget the plywood top and use a solid surface for top.

Finished

What’s a plywood top going to do for deflection?

Braced correctly with one to two stretchers and secured a plywood top works great. Just do not get the plywood wet, the reason I suggest a solid surface.

 

[workhz]

Length wise, nothing. It'll triangulate the rectangle but add essentially nothing for vertical support, deflection, warping.

That was my understanding also. Not sure why people think a plywood top is going to do much of anything in terms of structural support.

 

[jsker]

Most over build a stand. The sag in stands are usually caused from the floor the under the stand over time and the tanks crack from the stress of a uneven floor, also not making sure the floor joist are at the least a 2"x10" or 2"x12".

If you have 2" x10" joist, laminate another 2"x10" to each joist under the tank. Then you will have enough to support the weight.

 

[Lost in the Sauce]

That was my understanding also. Not sure why people think a plywood top is going to do much of anything in terms of structural support.

Who knows. The plywood, if properly attached does make the stand stronger.

Unfortunately, the ways it strengthens, is in a manner that doesn't really matter unless you're trying to crush it lengthwise.

It will not help with center sag or twist of the stand in a meaningful way, which are the two biggest concerns.

 

[Rit6942]

Most over build a stand. The sag in stands are usually caused from the floor the under the stand over time and the tanks crack from the stress of a uneven floor, also not making sure the floor joist are at the least a 2"x10" or 2"x12".

If you have 2" x10" joist, laminate another 2"x10" to each joist under the tank. Then you will have enough to support the weight.

My stand is going on the 1st floor of my house......which is a concrete pad/floor.

 

[jsker]

That was my understanding also. Not sure why people think a plywood top is going to do much of anything in terms of structural support.

The weight of the tank is on the four corners. With the newer rimless tanks, over kill is having a long support in the front and back with the plywood fasten only not glue to prevent racking/flexing of the box since most have an open back and doors on the front.

a solid surface would be set in place with silicone so the the wood cabinet can expand and contract as the surface is solid and dose not move.