3/4" ply strong enough?

Amaroq · Jan 7, 2020

Hi all, simple question. I've been thinking of buying a new larger metal tube stand so I can store practically all my system equipment within the stand. Plan was to buy a standard metal 120g, 48"x24"x28", stand and move my standard 40B system over onto it. Do you think after placing a sheet of 1/2" styrofoam beneath a 3/4" sheet of birch handy panel 13ply would safely longterm support the 40B? I know the stand itself can handle the weight, but since the 40B won't actually be on the metal frame but rather "inside" the frame and thus fully bearing its weight onto the plywood. The goal here is to have my ATO res, Salt mixing tank, sump, and frag tank all on the bottom 48"x24" section of the stand with just the 40B on the upper section. It also gives me future proofing for when I wanna finally go bigger again.... Am I just way underrating the strength of 3/4" plywood? haha

The Aquatic Arsenal · Jan 7, 2020

Would be able to brace the ends of the 40b underneath the plywood? I think that would give me peace of mind.

sharpimage · Jan 7, 2020

my 112 gallon stand is made completely of 3/4" ply.
So was the stand under my previous 300 DD

motortrendz · Jan 7, 2020

Can you weld a few cross braces into the top.of the stand to support the actual load of the tank.

Amaroq · Jan 7, 2020

No unfortunately I wouldn't be able to add more braces as I wouldn't be making the metal stand, just one from the LFS.

motortrendz · Jan 7, 2020

The 3/4 can handle the weight but itll also flex without supports. So eventually the tank will sag. Expecially if the wood gets wet.

pdxmonkeyboy · Jan 7, 2020

I dont think that it will flex at all really. The weight is distributed over the entire footprint of the tank, not the middle.

If you are the nervous type then just screw a 2x4 on its edge to the bottom of the ply. Screw it 3" OC the whole length.

Completly overkill, but that is how you would increase rigidity

Amaroq · Jan 7, 2020

Hm...well I'm glad I asked. What about something even sillier, two 36"x12" metal tube stand butted together to make one 36"x24" stand, then the 40B would be spread across 2 beams under the ply in the center and both short ends fully on top the metal frame? Would mean I need to be a little more creative as I'd be down a 20g underneath the display but theorecitcally it would better supported up top?

crusso1993 · Jan 7, 2020

Amaroq said:
Hi all, simple question. I've been thinking of buying a new larger metal tube stand so I can store practically all my system equipment within the stand. Plan was to buy a standard metal 120g, 48"x24"x28", stand and move my standard 40B system over onto it. Do you think after placing a sheet of 1/2" styrofoam beneath a 3/4" sheet of birch handy panel 13ply would safely longterm support the 40B? I know the stand itself can handle the weight, but since the 40B won't actually be on the metal frame but rather "inside" the frame and thus fully bearing its weight onto the plywood. The goal here is to have my ATO res, Salt mixing tank, sump, and frag tank all on the bottom 48"x24" section of the stand with just the 40B on the upper section. It also gives me future proofing for when I wanna finally go bigger again.... Am I just way underrating the strength of 3/4" plywood? haha

Your plan is good. However, if you have any doubts or it might keep you up at night, then simply double up on the 3/4" ply. Doubled 3/4" ply is much, much stronger than comparative dimensional lumber. Plus there will be no concern of twisting or warping.

Good luck and happy reefing!

Amaroq · Jan 7, 2020

Doubling the plywood makes total sense and frankly would be much easier as it would just require one more 48"x24" panel from Home Depot, plus I get a slightly higher stand!

crusso1993 · Jan 7, 2020

Amaroq said:
Doubling the plywood makes total sense and frankly would be much easier as it would just require one more 48"x24" panel from Home Depot, plus I get a slightly higher stand!

LOL!

pdxmonkeyboy · Jan 7, 2020

only kooks buy anything but full sheets of plywood..... your father should have told you this

BrandonS · Jan 7, 2020

my 93 gallon cube stand is entirely made of 3/4 ply. no issues or flexing and the tank sits 2 inches in off all edges.

zalick · Jan 7, 2020

For piece of mind, I wouldn't.

I had two 55 gallon brutes on a piece of 3/4 ply for my mixing station. It absolutely flexed over time.

If the ply flexes, it could put odd stress and angles of force on your tank's glass.

My 300g is sitting on 3/4 ply but the edges of the tank are directly above the support structures.

Redleg · Jan 7, 2020

Amaroq said:
Doubling the plywood makes total sense and frankly would be much easier as it would just require one more 48"x24" panel from Home Depot, plus I get a slightly higher stand!

Make sure you glue them together, and seal the edges.