Plywood Cabinet Design Review

Yoder · Sep 9, 2021

Hey R2R,

First post here (I think). I'm totally new to the saltwater world, and am looking to setup a SCA 120 gallon eurobraced tank. I'd like to tackle building the stand/cabinet myself, but I'm no woodworker. But, with a little help from a few friends, I think I can get it done.

Could someone more wise than myself look at my design and give me a go/no-go? All wood will be 3/4" birch (not Baltic probably, just the HD/Lowes 7 ply), Kreg Pocket screws w/ Titebond III, concealed euro-hinges with a 1.5" overlay.

Thanks!

Biglew11 · Sep 9, 2021

I would build a 2x4 stand to hold the weight. Then skin that with the plywood to make it look nice.

Yoder · Sep 9, 2021

Biglew11 said:
I would build a 2x4 stand to hold the weight. Then skin that with the plywood to make it look nice.

Thanks, that was my first thought as well, until I saw threads like this one. A RocketEngineer style 2x4 stand seems like you could park a Humvee on it. If I did that I'd skin it in something a lot thinner than 3/4" plywood.

I hate losing so much interior volume to 2x4's, and would like to achieve the clean look of the Red Sea/Waterbox cabinets (From what I gather, most of those are MDF, and I definitely wouldn't use MDF)

Sleepingtiger · Sep 9, 2021

Yoder said:
Thanks, that was my first thought as well, until I saw threads like this one. A RocketEngineer style 2x4 stand seems like you could park a Humvee on it. If I did that I'd skin it in something a lot thinner than 3/4" plywood.

I hate losing so much interior volume to 2x4's, and would like to achieve the clean look of the Red Sea/Waterbox cabinets (From what I gather, most of those are MDF, and I definitely wouldn't use MDF)

if you look at stands built by Oceanic, Red Sea, Waterbox.... they have no 2x4. At most they have are 3/4"x3" boards out of poplar. My Oceanic 180g bowfront was made out of 100% mdf. 2x4 I think are way overkill. They are ugly and take up way to much space in the already crowded area under the stand.
What you have to worry about is the plywood overtime bending due to the weight of the aquarium. If you reinforce it with 3/4" x 3", just like your design, you will be fine. Not sure if you are staining or painting... but I would go with a dense wood like beech.

For me, a cabinet build has to be not just strong, but it has to be functional and looks good. This is your cabinet, imagine the possibilities.

I like your design. Several things I would add to your design. Add support to the middle divider. Add a drawer on the right had side. Stay away from pocket screws. I know you probably don't have the tools, but think about a dowels. If you got a friend who is a carpenter... ask if they have a domino so you can make floating tenons. If you can't do dowels or have a domino, I would countersink and use wood screws. Then fill in with a dowel or putty.
Add soft close hinges to avoid scaring the fish when the cabinet door is closed.

Think about the sump, the equipment. How can you organize things to make it look good. What happens during a spill?
If you are painting, get a marine paint like topside. Its expensive, but you know the plywood wont swell and fail when you have a leak.

What are you doing with the right side? Maybe a control panel that is on drawer slides that you can pull out?
Research cable management. You will have a crap load of cables to contend with.

For me, this is not just a reef tank, its a piece furniture that not only showcase the tank, but your equipment.

Check out the stand I built for my 95g cube. Its in my build thread.

um_fan5 · Sep 9, 2021

I did a similar design to the OP and took my inspiration from the RSR, Waterbox stands!
They all use 3/4 ply!
My stand is 63 x 23.25 x 33. Left the the 3/4 in the from for the cabinet doors.
That way, doors would be flush with the tank when closed.

What I did...doubled up on the 3/4 to create 1.5 for the sides and 21" on center for "middle"
Plywood were glued together
Used 2x6 on the top and 2x4 on the bottom.

I do 1000% agree with @Sleepingtiger "this is not just a reef tank, its a piece furniture" and needs to be functional and not have it look like it belong in the garage!

Edit: I did not use ply made from Pine...I used Hardwood Ply

alton · Sep 9, 2021

Baltic Birch from Russia is an aquarist dream for building aquarium stands. No warping and it is exterior plywood that will last a lifetime.

Sleepingtiger · Sep 9, 2021

Here is a stand I completed for a customer a few weeks ago. Made of Baltic birch. It was for a saltwater setup. Customer wanted drawers and an area for his canister filter.

Sleepingtiger · Sep 9, 2021

Here is my current build.

rossco · Sep 9, 2021

Take a look at the first couple post of my build thread. Still rock solid after 10 years.

Build thread

alton · Sep 9, 2021

Sorry I missed this but welcome to R2R. Its a great place with a lot of info

Yoder · Sep 10, 2021

Thanks for the replies! Those are some beautiful stands!

Sleepingtiger: I agree about it being a nice looking piece of furniture, that's what I'm shooting for! I hadn't considered a drawer, but now I am.

The right side of the tank is where I plan to do cable management, power distribution, etc. I know pocket joints aren't as good as traditional joinery, but no fasteners will be supporting the weight of the tank, I'm relying on the tank to floor 3/4" ply back and sides, along with the 1.5" (doubled up) corner supports and front beam to distribute that load.

I'll use copious amounts of waterproof wood glue, and do pockets every 6-8". Sadly, I just don't have access to more advanced joinery tools. Thanks for the paint idea, I'll definitely go that route, at least on the interior. I'll be using a hardwood (birch) plywood.

It's my first reef tank, so there's a lot of things that are "fuzzy concepts" for me still, despite watching 9000 hours of BRS YouTube.

Yoder · Sep 10, 2021

Some more pics that hopefully clarify a little...

Corners:

Yellow colored to show load bearing pieces, green are secondary support/anti-racking (hopefully)

Thanks again to everyone for your input, idea, etc, it's much appreciated!

Randomwhiteguy89 · Sep 15, 2021

I like your design my only advice would be to build a frame inside the stand out of 2x4’s and replace those 4 vertical pieces you have with 2x4’s and make sure the frame is resting on the 2x4’s not screwed into the side of them that will give your tank all the strength it needs without a doubt I edited your last photo I will apologize in advance for my crude drawing but it should get the point across lol

Randomwhiteguy89 · Sep 15, 2021

I believe 1 vertical 2x4 can hold something like 1000 lbs before it breaks so with just that top frame and the 4 2x4’s your stand can already hold roughly 4000 lbs but you have to make sure that frame is resting right on top of the but of the 2x4 if you attach it any other way your losing strength and relying on the strength of the screws which I believe has a Breaking point of around 50lbs per screw which means even if you put 4 screws in each 2x4 it will technically only hold about 800 lbs.

Yoder · Sep 16, 2021

Randomwhiteguy89 said:
I believe 1 vertical 2x4 can hold something like 1000 lbs before it breaks so with just that top frame and the 4 2x4’s your stand can already hold roughly 4000 lbs but you have to make sure that frame is resting right on top of the but of the 2x4 if you attach it any other way your losing strength and relying on the strength of the screws which I believe has a Breaking point of around 50lbs per screw which means even if you put 4 screws in each 2x4 it will technically only hold about 800 lbs.

Thanks, I've watched a bunch of 'King of DIY' on YouTube, with his 2x4 stands, that's what got me started on this path. Then I noticed all the commerical stands are made of plywood or (gasp) MDF, and started heading down that road, mainly because I don't like all the internal space consumed by the massive frame.

I know having the load from tank to floor is really important, as the shear strength of screws can't hold up, as you mentioned. (My design also has no load which is bearing on screws)

Personally, I feel like 1.5" (~14 plys) of birch hardwood is a lot stronger than a 1.5"x3.5" piece of soft lumber (the actual size of a 2x4).

Thanks for your reply and input. I've got a while before I actually start building the stand, so I've got time to brainstorm and revise. I've got a newer revision of the design I'll post when I get to a PC.

Poof No Eyebrows · Sep 16, 2021

Welcome
I think there is no reason why you can’t or shouldn’t use 3/4” plywood. The most crucial aspect will be your joinery. I would use a combination of dado cuts to set the pieces together and use glue. If done right I bet it could actually be stronger then many of the 2x4 cabinets we see.

Yoder · Sep 18, 2021

Here's some pictures of the revised design I've been working on. I've decided to go with Russian Baltic Birch. It's a lot more expensive, but if it's a stand I plan to keep for a long time, it's worth it.

SCA 120 gallon drilled for Synergy Shadow V2 - 40 gallon breeder DIY sump

The front center brace I'll make removable (when the DT is empty), like the SCA PNP stand is.

knockout · Jun 1, 2022

@Yoder did you build the stand? would love to see your final design and finished product.

Yoder · Jun 1, 2022

knockout said:
@Yoder did you build the stand? would love to see your final design and finished product.

I ended up having a guy I work with build the stand for me, not exactly to these plans. He's a really experienced woodworker, and he made a few deviations.