DIY Assistance

[sde219]

So I'm building a stand for a 22x22x20 Glasscages cube tank. I'm planning on doing four 1.25 by 5/8 legs between a sheet on plywood on the top and bottom. There will be cross bracing between the legs to prevent sway in the stand....however, I was hoping to just connect the legs to the plywood on top by countersinking two screws for each leg. All four corners of the will actually rest on the legs so it will be direct support. My question is whether 1/2 birch plywood will work for the top or if I should use the 3/4 oak I have available. I prefer the birch because of it's appearance but I don't want to compromise on strength. Any thoughts? Is the thickness of the plywood irrelevant since the tank is directly above the legs?

 

Steve

[Ne0eN]

Just some quick calculations: 42 gal --> 350 lbs of water + weight of the tank + weight of salt + weight of LR + weight of substrate, etc... You're looking to support at least 450 lbs!!! How tall are you planning on making this stand? I would use 4x4 for the legs.

Edited May 11, 2005 by Ne0eN

[flowerseller]

If you build that........

It will sway

 

YGM

[Ne0eN]

...and crash!!!

[ErikS]

Not sure if I get the picture correctly - but you're saying you just have two sheets of plywood with 4 legs, one at each corner?

 

Two problems, sway & sag in the middle. Plywood has good rigidty....but...given the span you'll need something to help support the edges. Not sure even 3/4" can hold up across that span w/o a bit of sag. You might consider two boxes with ply across the top & bottom. Also, factor in that a glasscages tank requires full support across the bottom, it doesn't rest on the edges like an AGA or Oceanic. For the lateral support you could either use triangles in the corner or cover the back w/ 14" material - either will provide plenty of support (you can remove 80% of the 1/4" if you want the back open).

[Grav]

I recently built a stand for a 150g acrylic, I belive the stand I built would hold at least 2* the aproxamate TON my tanks tips the scales at... yet can be moved by one man, and looks pretty good IMHO. Here are a few things I learnt:

 

Pine has a greater compression strength then most think. About 750 pounds per sq inch. Therefore, the critical issue is making strong joints...

The added benifit to thicker, bigger legs is that they make jointing easier, not in their "up-down" strength.

Glass tanks need no support other than the 4 corners, therefore most commercial stands have no "top." Acrylic tanks need full support across the bottom of the tank.

You can find nice, cheap, unfinished oak (or whatever) doors on the internet.

Liquid nails and gorilla glue are outstanding.

 

I would not feel good about the joints you are considering.

[HowardofNOVA]

Hey Steve,

Are you back in town now?

Got your light bulbs and money?

 

Take a look at my link in DIY on building a stand. The layout would be the same for you to do for your cube, just dimensions to change.

Use 1/4" Hardwood Plywood on the out side for appearance.

Give me a call when you have a moment?

Howard

[sde219]

Just some quick calculations: 42 gal --> 350 lbs of water + weight of the tank + weight of salt + weight of LR + weight of substrate, etc...  You're looking to support at least 450 lbs!!!    How tall are you planning on making this stand?  I would use 4x4 for the legs.

31197[/snapback]

 

Exactly what size legs would you use on a 180g tank? 4x4s are massive overkill. If you take note from commercially available stands - 1x3s and 1/2 plywood are sufficient up to around 90g probably higher. I will say I wish I was only looking at 450lbs - I figure it will be closer to 600 since this tank is low-iron and quite a bit heavier than standard plate glass.

 

I appreciate the offer of advice but I rather be realistic about this.

 

As for height. the stand contains an internal shelf around 30". The top of the stand will be around 50" I guess. And the tank will span the area up to 70". These are roughly accurate but wood thickness will affect the exact height.

[sde219]

Not sure if I get the picture correctly - but you're saying you just have two sheets of plywood with 4 legs, one at each corner?

 

Two problems, sway & sag in the middle. Plywood has good rigidty....but...given the span you'll need something to help support the edges. Not sure even 3/4" can hold up across that span w/o a bit of sag. You might consider two boxes with ply across the top & bottom. Also, factor in that a glasscages tank requires full support across the bottom, it doesn't rest on the edges like an AGA or Oceanic. For the lateral support you could either use triangles in the corner or cover the back w/ 14" material - either will provide plenty of support (you can remove 80% of the 1/4" if you want the back open).

31208[/snapback]

 

The tank may not "rest of the edges" but you can support the weight at a number of points. I was debating about doing boxes for the for top and bottom. But are they necessary? I was gonna run some pieces between the legs at the top, bottom, and middle not just between the front two or the sides but alternatingly probably - linking all of them at the top, the sides and the back at the middle-although the shelf will do that anyway, and just the sides at the bottom.. That should minimize the potential for sway. The sides and back will probably have 1/4" ply with 90% of the remaining present. Do you really think the ply is gonna sag across a 24" span where a 3"x1.25" area of the tank is directly above the support legs? I mean that implies that the bottom glass is going to bow quite a bit. If the sheet were longer or wider I miht be considered about this but 22x22 isn't too large.

 

I will definitely consider using boxes at the top and bottom. I'm pretty torn on whether they are really necessary. What are your thoughts Eric? Btw I planning on running my AP600 and I'm looking forward to seeing the production you've got - thanks for putting your pics up.

 

Steve

[ErikS]

But are they necessary?

I'm not a structural engineer so my best answer is "I don't know"

 

Given that plywood's weakest point is across a span I might just go with the overkill. I do know that glasscages tanks are for the most part flat bottomed so I would think the more support the better. It doesn't take much to stiffen ply & I'm sure you wouldn't need much to add the required support. As you say it's not much of a span & given that even the 22" will be dramaticly reduced??? But then again we have little room for deflection when it comes to stands (far from the failure point).

 

So, hows that for a non-answer answer

 

I can't say enough good things about the AP600 - it's still pulling almost that much gunk from the tank every 24 - 48hrs. I've recently added ozone, but that's a tiny bit infrequently. About the biggest knock I can give it is that it takes a few hours to resume skimming after a feeding or cleaning - nothing that makes a difference though (no settings need be changed). The funniest part of the skimmer is that the skimmate is a medium color but when you clean it the "chunky" stuff that sticks to the walls & tube smell terrible (like a sewage treatment plant).