# Plywood for aquarium stand/shelf?



## RandomMan (May 31, 2011)

Hi, I'm going to be making some shelves to hold some small aquariums (think a long stand along the wall or a rack). I'm trying to decide on the material to use for the actual shelf the tanks will sit on I don't expect it to be continually wet, but I'm sure water will get on it from time to time, not to mention humidity.

For that reason, I know MDF is out.

Can I use the outdoor plywood they use for siding? Or do I need to spend the bucks for double sided MDO (Medium Density Overlay) which is what they use for making outdoor signs? 

I don't want the wood to warp or rot from getting wet.

One more question, is 1/2" thick enough, or should I go to 3/4"? The plywood will be supported around the edges, not all the tanks will go all the way to the support.
I've used planking in the past, but its just too expensive and comes in the wrong sizes. A 4x8 slab of Plywood will be perfect size wise.


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## proaudio55 (Oct 20, 2011)

What dimension tanks are you talking here? Like 5 or 10 gallon aquariums or micro betta tanks or . . .?


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## Bushkill (Feb 15, 2012)

Same question here. But to be honest, if you have the ability to work with a full 4X8 sheet, you would be cutting corners if you didn't just go to 3/4". Heavier but not by much, and in the long run will give you more flexibility if things change (bigger tanks, etc.).


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## AaronT (Apr 11, 2004)

I would spring for the 3/4" MDO myself if you want it to last a good long time. I think it's about $60 / sheet, which isn't cheap, but still much cheaper than buying a shelf system.


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## proaudio55 (Oct 20, 2011)

Unless you've sat down and run the engineering calculations on what material you're working with (and know exactly what you're doing) my advice is always to overbuild DIY stands. That said, I would go for 3/4" material. To make it last, I would use a quality varnish to seal up the wood. That will keep any splashed water from soaking in. 

As for what weight you need to support. A safe rule of thumb is to estimate about 12 pounds per gallon (that covers water, glass, substrate, etc). So figure a 10 gallon is around 120lbs, 5 gal is 60lbs, and a 120 gal is 1,400 lbs. :wink:


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## GraphicGr8s (Apr 4, 2011)

Use a birch plywood for the stand. 3/4" all the way around. If you seal it with polyurethane on all sides of the plywood, 3 coats at least, you shouldn't have any water problems. Stay away from treated products. 
You could also just use 2 x 4's to support the tanks (no plywood at all under the tanks) and put 3/4" plywood between the tanks for shelving. Glass tanks only need support on the edges. The guy I got my breeder tanks from had them on 2 sticks of galvanized piping running down the hatchery. No other support under the tank. Just the 2 long sides is all.


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## James (Western Canada) (Mar 25, 2012)

Somewhere in a recent thread, I saw mention of this product, it sounds like it would be a good start to protecting your wood....

http://www.rotdoctor.com/products/cpes.html

James
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RandomMan said:


> Hi, I'm going to be making some shelves to hold some small aquariums (think a long stand along the wall or a rack). I'm trying to decide on the material to use for the actual shelf the tanks will sit on * I don't expect it to be continually wet, but I'm sure water will get on it from time to time, not to mention humidity.*
> 
> For that reason, I know MDF is out.
> 
> ...


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## Hoppy (Dec 24, 2005)

Wood doesn't rot from getting wet, nor does MDF deteriorate from getting wet. Both are damaged if they are continuously wet for a long time. Wood is used for bathroom sink cabinets all the time, both plywood and MDF, and they both last a long time in that damp humid environment. If your aquarium stand is wet more than occasionally you have leak somewhere or very careless techniques around the tank.


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## RandomMan (May 31, 2011)

Thanks for the feedback everyone. To answer a few questions:

This will be mostly 5 gallon tanks laid out next to each other, although there will be a few odd balls. The 5 gallons will have their ends directly over the supports, but the odd balls may not.

In regards to MDF, I've seen mixed results from people. I've had some say it "puffs up" from just a little water exposure like cheap particle board does, and I saw someone who bought a commercial steel rack for their aquariums, which came with melamine coated MDF, say that after a year the MDF was starting to rot. I've also seen others who say they've made garden posts out of it and left it in the ground for a year without issue.

I probably should just spend the extra money and go with MDO, but I'm a cheap bastard. I also don't have a lot of room to apply sealant to wood (without the dogs getting to it) so I want to avoid having to do that. I've heard pressure treated sheathing may release fumes, so that's why I'm avoiding that. 

Also after doing some reading, I was surprised to learn that a lot of boat builders use MDO. Not too shabby.


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## GraphicGr8s (Apr 4, 2011)

Hoppy said:


> Wood doesn't rot from getting wet, nor does MDF deteriorate from getting wet. Both are damaged if they are continuously wet for a long time. Wood is used for bathroom sink cabinets all the time, both plywood and MDF, and they both last a long time in that damp humid environment. If your aquarium stand is wet more than occasionally you have leak somewhere or very careless techniques around the tank.


Hoppy, they also use particle board for countertops. Heck they use it for the cabinets themselves.


Randomman, are you going to paint the stand or leave it bare wood? If your going to paint it then you can use a waterbase poly instead. It's try to the touch in just a short time. You can get 3 coats on easily in one day and there is very little to almost no odor with the WB poly that I've noticed. Just do it after the stand is built.


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## RandomMan (May 31, 2011)

I'm not planning on painting it, for the same reason I don't want to treat the wood myself. I have a limited area to work in, and anything that involves wet sticky stuff will quickly get dog hair in it, if not the dog itself.


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## wastedtime (Oct 27, 2011)

Hoppy said:


> Wood doesn't rot from getting wet, nor does MDF deteriorate from getting wet. Both are damaged if they are continuously wet for a long time. Wood is used for bathroom sink cabinets all the time, both plywood and MDF, and they both last a long time in that damp humid environment. If your aquarium stand is wet more than occasionally you have leak somewhere or very careless techniques around the tank.


This ^ :thumbsup:


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## RandomMan (May 31, 2011)

I ended up going with MDO. I was surprised how cheap it was. $38 for a 4x8 sheet, not that much more expensive than a decent plywood. And if I ever get into boating I can tear it out and using it for shealthing the boat. 

Sent from my MSM using Tapatalk 2


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## GraphicGr8s (Apr 4, 2011)

RandomMan said:


> I ended up going with MDO. I was surprised how cheap it was. $38 for a 4x8 sheet, not that much more expensive than a decent plywood. And if I ever get into boating I can tear it out and using it for shealthing the boat.
> 
> Sent from my MSM using Tapatalk 2


Not sure where you are but down here a decent plywood is $45.00 per 4 x 8 sheet. There is cheaper but you did say "decent".


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## rcoups (Apr 12, 2015)

I want to build a shelf unit into a wall between 2 studs that are 27.5" apart. This was an area surrounding an old woodstove chimney. I plan on using 3/4" birch plywood. The shelves will be 27" wide and attached at the ends in dados. I want to get a 15 gallon bowfront tank that would weigh about 180 lbs. loaded. Would this shelf support the weight?


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## Immortal1 (Feb 18, 2015)

I have a 75 gallon tank and I opted to use plywood for the structural portion of the stand. I probably over did things a bit but, I only used 1 sheet of 3/4" for the entire structural portion. If interested, there are a lot of pics in my build thread listed below.


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## ichy (Apr 6, 2015)

are you handy enough to put a countertop laminate on? lots of color choices and pretty indestructible.


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## lochaber (Jan 23, 2012)

I have a stand that fits a 10 gallon tank made out of 2x12 - it's super easy, and pretty strong - just use a circular saw to cut some dados in the uprights, and then set the horizontals in them. (I'll try to attach a pic, since I'm not terribly good at describing things)

You can even build it without measuring, if you cut the uprights and shelves together (cut the 2x12 in half and make all the cuts across both boards simultaneously), and do the same for the dados.

It should work for smaller tanks too, what's a 5 gallon, ~8.5" wide? so you could use a 2x10 for that.


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## Hoppy (Dec 24, 2005)

rcoups said:


> I want to build a shelf unit into a wall between 2 studs that are 27.5" apart. This was an area surrounding an old woodstove chimney. I plan on using 3/4" birch plywood. The shelves will be 27" wide and attached at the ends in dados. I want to get a 15 gallon bowfront tank that would weigh about 180 lbs. loaded. Would this shelf support the weight?


No, it wouldn't support the weight well. It would sag away from the load, where possible, leaving the tank supported at the ends. Plywood will gradually warp from loads of any kind unless it is reinforced with wood strips at the edges, so the strips make the shelf look like it is 2-3 inches thick. I have seen many bookcase shelves that were permanently bowed from the weight of the books.


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## hamstermann (May 10, 2007)

you could also add strength and prevent bowing by adding vertical supports under the shelves every so often. 

Also, for calculating how much bow there will be in wood over distances, the sagulator is very helpful: http://www.woodbin.com/calcs/sagulator.htm


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