DIY Stand.. Do I need to worry about this?

[cpark645]

Hello R2R,

I am totally new to woodworking, but I am thinking about building my own stand for a 48x24x16 setup. I know there's a ton of guides out there, but it seems one thing doesn't get mentioned too often..

Do I need to worry about the 2x4's being not perfectly square? I'm worried because I don't have a planar/jointer, I won't have perfectly square 2x4's which could throw off how square the whole stand is.

 

[paphater]

Just go through the wood piles and get the straightest pieces you can find and you'll be ok.

 

[bobman]

The tank must sit flat on the stand. If not it will cause stress on the glass and the tank will fail. I have made plenty of stands and I dont have a plainer. As long as you get the straightest boards you can it will be fine. Once complete run a credit card along the mating surfaces on the tank and stand it should not be able to fit in between the tank and stand

 

[Billdogg]

I would suggest using a piece of 3/4 plywood on top of the 2x4's. It will be flat so that you can easily see where the stand itself might not be. You can then insert shims as need before you fasten it down. Remember to use glues and screws, not just screws themselves during assemble. The screws are there more to hold it together while the glue dries than they are to provide structural support.

Follow the standard "Rocket Engineer" template and you will be fine.

 

[cpark645]

Thanks everyone for your advice!

 

[trustmeimalawyer]

Agreed with the advice so far. No way for you to get truly perfect 2x4s but the way to address this is to skin it properly and place a flat plywood sheet on top. I just finished building my stand and had the same issues, as you can see in the pics. I ran into a couple issues with my 2x4s not lining up but everything got squared up once I skinned the stand.

 

[MrPike]

Shimming the stand when it's complete helps as well. If your floor isnt straight, sometimes the stand will rock, don't allow this. Throw a level on it, and use shims to get it right.

 

[cpark645]

Drew up a SketchUp of a plywood stand.

Essentially using 3, 3/4'' birch plywood boards, front won't have any support. Using 2x4s to make a frame on the bottom, and will put another 3/4'' on top of that. Will put it together using glue and kreg jig.
I like it because it gives me a lot of room in the stand, but I'm worried if it will be strong enough. Any advice?

Finished one:

 

[Retro Reefer]

Drew up a SketchUp of a plywood stand.

Essentially using 3, 3/4'' birch plywood boards, front won't have any support. Using 2x4s to make a frame on the bottom, and will put another 3/4'' on top of that. Will put it together using glue and kreg jig.
I like it because it gives me a lot of room in the stand, but I'm worried if it will be strong enough. Any advice?

Finished one:

I would not trust that without internal framework, you may be able to use 1x3’s instead of 2x4’s if you are using 3/4 birch as long as everything is glued and screwed really well

 

[davocean]

So that front rail has no support other than screws fastened to it?
No I would not trust that last sketch.

Also in getting advice, I see you are in orange county, don't forget earthquakes, we have to really make sure our stands do not rack.

 

[Matthew Frost]

Plywood stands IMO are not meant to carry the loads long term for a couple of reasons. It is very difficult to adequately brace the stand and support the tank using only plywood. There are some stand manufacturers that do it but with a fair amount of engineering and specialized wood products. Plywood products from your local Big Box hardware store simply aren't engineered to be exposed to those levels of moisture for long periods of time, it breaks them down. Your best bet is a lumber product like a 2x4 or 2x6 for load carrying and then a plywood product to skin the stand and for shear strength.

I have been a woodworker for two decades and owned fish tanks longer than that, my philosophy has always been over build. I don't ever want to come home and find a stand failure caused a tank failure.

 

[dutch27]

I have to disagree that plywood stands can't handle a tank. I had a 75g on a custom built oak stand where the framing was entirely 3/4" plywood (oak). Plywood can handle a compressive stress perpendicular to the plan of the plys in excess of 1000psi, assuming it's quality ply. That means you can apply 750 pounds to a 1" length of the plywood before it fails. The dimensions he notes adds up to around 80 gallons, which is 640 pounds, which would be spread out along the plywood frame. That plywood frame will barely feel the tank.

The only change I'd make to this sketch is a support to that lone header up front. A 2x4 likely won't deflect much under the tank at such a small span and load, but you may want to add a small center support under that board. I'd suggest making your frame dimensions such that the perimeter of the tank would site in the center of the vertical plywood, then oversize the plywood top so you can add some finish trim underneath it. Once it's done stain it (or not) then add a couple coats of poly. My stand had 2-3 coats of poly and has stood up to 3 different tanks over the past 8 or so years.

 

[cracker]

I'd think, You want (upright) supports in the corners at least. Also At each end off the front top. This is a 4 ft run? Again I think that is too long a run across the front with out a brace. If the tank is smaller You should be ok.

 

[cpark645]

All right. Y'all got me quite nervous now.

The reason why I left the front without a support is b/c the sump I am planning on using is 36'' long, so it won't fit if I put a center support.

@cracker Per your suggestion I've added some 2x4 upright supports in the corners, and a 2x4 frame at the top. Do you guys think this would be sufficient?

 

[cracker]

Good job in the corners. It's a 4 ft run from left to right? The tank is how many gallons? A 75 or 90 perhaps? Sorry if I missed that part.
I don't know about that long without support. I'd like to hear what others say also before suggesting anything.
I understand about wanting to pull the sump cause I have the same issue. Wasn't concerned about it cause I thought I had it all worked out . Well, of course I didn't.

 

[cpark645]

Good job in the corners. It's a 4 ft run from left to right? The tank is how many gallons? A 75 or 90 perhaps? Sorry if I missed that part.
I don't know about that long without support. I'd like to hear what others say also before suggesting anything.
I understand about wanting to pull the sump cause I have the same issue. Wasn't concerned about it cause I thought I had it all worked out . Well, of course I didn't.

It's a 48x24x16 tank, 80 gallons. For its LxW, it's a light tank b/c it's shallow.

I've read that a standard 2x4 frame stand doesn't need center braces until the length is greater than 48. But I'm definitely a novice so I want as much input as possible.

Thanks everyone for all the advice, this community is amazing!

 

[Matthew Frost]

The 2x4's should be sufficient without a center brace, a 2x6 is only $2 more and would be guaranteed to cover that span and not sag.

The big reason I stay away from building/owning plywood stands is the moisture exposure. If you're making sure there is no moisture exposure then its better. "Most" commercial grade plywoods are laminated with water soluble glues. There are some marine grade and other special furniture grade products but they are expensive and hard to find.

 

[cpark645]

The 2x4's should be sufficient without a center brace, a 2x6 is only $2 more and would be guaranteed to cover that span and not sag.

The big reason I stay away from building/owning plywood stands is the moisture exposure. If you're making sure there is no moisture exposure then its better. "Most" commercial grade plywoods are laminated with water soluble glues. There are some marine grade and other special furniture grade products but they are expensive and hard to find.

I was thinking I'd paint the inside with waterproofing paint to help with that problem. As for the type of plywood, I've read many people use birch for their plywood stands.. so I'll be going with that.

 

[Sleepydoc]

Plywood stands IMO are not meant to carry the loads long term for a couple of reasons. It is very difficult to adequately brace the stand and support the tank using only plywood. There are some stand manufacturers that do it but with a fair amount of engineering and specialized wood products. Plywood products from your local Big Box hardware store simply aren't engineered to be exposed to those levels of moisture for long periods of time, it breaks them down. Your best bet is a lumber product like a 2x4 or 2x6 for load carrying and then a plywood product to skin the stand and for shear strength.

I have been a woodworker for two decades and owned fish tanks longer than that, my philosophy has always been over build. I don't ever want to come home and find a stand failure caused a tank failure.

First, a plywood top will not fix an uneven stand, and if you've gotten to the point of putting plywood on the top and find out it's uneven you've got to start over.

The main problem with Rocket engineer's template is that it uses 2 x 4's. They are overkill for what's needed and straight 2x4 stock is very difficult to find. (if you're interested, look up the compressive strength of various types of wood. 1x4 stock skinned with plywood is more than adequate.

My current stand is made of hickory 1x4s at the corners with a double laminated 1x4 across the front so I don't need a center brace (48" wide 120 gallon tank.) The really ironic part is, after I finished the stand and put my tank on it, I noticed a slight gap under the center of the tank, just enough to slide a business card into. A wave a panic went through me as I thought that the stand wasn't flat, despite my efforts. Well, it turns out that the stand was perfectly flat; the tank wasn't!

I would also disagree that plywood is not meant to carry loads. Not that I would hold it up as an example of fine woodworking, but the factory stand that came with my 120 was actually particle board. It was still solid when I replaced it after 3 years. I've seen plenty of well constructed plywood stands that have performed well for years. It's all about the construction. As for the plywood delaminating, first you need to make sure the stand is properly finished and sealed, then you need to make sure you don't have water getting on it. The humidity around the tank won't hurt the plywood and if you're getting enough water on it to damage it you've got other issues. In some ways, plywood is better since it's less likely to warp with humidity.

 

[Sleepydoc]

All right. Y'all got me quite nervous now.

The reason why I left the front without a support is b/c the sump I am planning on using is 36'' long, so it won't fit if I put a center support.

@cracker Per your suggestion I've added some 2x4 upright supports in the corners, and a 2x4 frame at the top. Do you guys think this would be sufficient?

You still don't have any support directly under the front cross beams.