Atomic's 750g Plywood Startup thread

[Atomic081]

Hello everyone,

Im in the process of building a new house (I build custom homes for a living). The framing is getting completed as I type. My goal is to have a inwall 750g plywood tank in the basement overlooking my mancave. The Tank is to be 120" long x 48" deep x 30" tall. Im struggling with a few things about my build right now and im hoping some of you all can help me make the hard discussions. My thought with the 10' long tank is because i can get 120" x 48" x 3/4" plywood from my lumber company. Its special order and kinda pricy, but I think the extra 2 feed will look amazing. If I get to the point where im not 100% confident in the 10' length holding up, ill downgrade to a 8' length. I have seen lots of 8' plywood tanks with success, but never seen a 10'.

Here is picture of what ive done so far. The framing is finished and the Plumbing for the sink is finished.

First my glass: Thickness and Annealed vs Tempered.

Ive contacted 3 of my local Glass companys that I use for homes to get there opinions between annealed vs tempered glass. They all believe that i should go with tempered glass for a few reasons. Its much stronger and can handle kids in the basments. Also they say if it breaks, the shards are small and while they will hurt children, they will not harm them like giant sharp shards of annealed. Lastly they all said that both tempered and Annealed glass both has the same problems strength in the edges. The only downfall of Tempered is that i can crack a edge with Annealed and Tempered would crack the whole thing. Im leaning toward Tempered but wanted other opinions.

I also have done my limited research on these boards and I tend to lean toward a piece of 3/4" glass for the front panel. Can anyone check this for me. I think it might actually be a bit of overkill. I figure that piece is gonna cost me around 1200 dollars.


Second: Plywood bracing: Double up plywood/Metal corners/2x4s

Because of the 10' length, I believe im going to need to address bowing in the back 10' wall. Also maybe beef up the corners as there is a extra 200g of pressure pushing on them compaired to a 8' tank. I plan on having the tank top braced with 2 front to back braces. Everything can be modified if someone can give me better ideas.

My first thought was to build a 2x4 wall around the back edge of the tank from floor to ceiling. While i think this would work well, it will make it horrible to work in the tank.

My second idea was to get a local welder to wield corner bracing around the corners of the tank and maybe 2 braces on the back side. I think this idea is my best structurally, but the tank will be saltwater, so rusting will be a huge issue. I plan on epoxying the whole outside anyway to prevent water from getting to the plywood.

The 3rd option was to double up the plywood on the whole tank to 2x thickness, glue and screw it together. I also could beef up the corners with extra wood. I think this would work, but wanted opinions.


3rd: Overflows

Do most people add the overflow after the tank is built on the back, or do they add them inside the tank. Is one easier?

4th: Rock Wall.

I plan on building a concrete/rock wall around the back 3 sides of the tank. I want to have 3 or 4 glass portholes to see in from the back, but generally i want the tank to look like a walled reef. Does anyone have any recommendations on how to mount it to the epoxy wall? I thought about adding a few mounting brackets somehow to the tank before epoxying. Then i can mount the concrete around the brackets, like they do with brick walls. Ideas?


Thanks everyone for the help

 

[Leebtattoos]

I can’t addess all of those. But 3/4” glass is good. 1/2” would work for 30” tall bit I agree 3/4 is way safer.

And the bowing. I would worry about the front more than the back. Since the window side has much less material, if it bows, you lose the silicone seal to glass like I just did on my 84x48x30” tank with doubled up 3/4 birch. *fix pending. But what I did was reinforce the entire lower section with 2x4/6/8’s as well as bulked up my top bracing (although it didn’t fail up high). But again, just something to consider. If it was me, I’d do more than 1.5” of plywood in the future for anything over 350 gallons.

 

[Atomic081]

I can’t addess all of those. But 3/4” glass is good. 1/2” would work for 30” tall bit I agree 3/4 is way safer.

And the bowing. I would worry about the front more than the back. Since the window side has much less material, if it bows, you lose the silicone seal to glass like I just did on my 84x48x30” tank with doubled up 3/4 birch. *fix pending. But what I did was reinforce the entire lower section with 2x4/6/8’s as well as bulked up my top bracing (although it didn’t fail up high). But again, just something to consider. If it was me, I’d do more than 1.5” of plywood in the future for anything over 350 gallons.

Thanks, ill look into the front. Ive never thought about it that way.

 

[Steve_C]

Sounds like a really cool project, and hope you're able to keep the 10ft length rather than 8ft. 8 would be nice too, but 10 is just that much nicer

Can't help with the questions on the plywood tank as I have not done a plywood myself, but on the rock wall I have a suggestion. Have you given any thought to maybe doing it out of foam and then coating it? I have done entire walls out of hand carved foam then coated with drylok to strengthen it and then painted to look like real rock. If you look in my "office 3.0" thread you'll see a pic of what I am talking about where I did an entire wall that way. Might make it easier to mount for your project as well as much easier to move if God forbid you ever had a tank prob and needed to get to the side/back of the tank board.

 

[Atomic081]

Sounds like a really cool project, and hope you're able to keep the 10ft length rather than 8ft. 8 would be nice too, but 10 is just that much nicer

Can't help with the questions on the plywood tank as I have not done a plywood myself, but on the rock wall I have a suggestion. Have you given any thought to maybe doing it out of foam and then coating it? I have done entire walls out of hand carved foam then coated with drylok to strengthen it and then painted to look like real rock. If you look in my "office 3.0" thread you'll see a pic of what I am talking about where I did an entire wall that way. Might make it easier to mount for your project as well as much easier to move if God forbid you ever had a tank prob and needed to get to the side/back of the tank board.

I have thought about the foam and it seems like the easier route to go, but im worred about long term with the foam. Im building this tank to hold up for a LONG time. Im never moving out of this house. So with that in mind, im gonna try to use the mortar and liverock.

 

[Leebtattoos]

One thing I realized, and not sure how o didn’t before, but if your glass is most of the size of the front panel, you won’t have the same issue as I did. Glass doesn’t bend obviously. I used a donor tank so the glass was a little smaller than I wanted for the overall size. Therefore there is more surface area of wood on the front allowing it to deflect under pressure. Design flaw on me end.

 

[Atomic081]

One thing I realized, and not sure how o didn’t before, but if your glass is most of the size of the front panel, you won’t have the same issue as I did. Glass doesn’t bend obviously. I used a donor tank so the glass was a little smaller than I wanted for the overall size. Therefore there is more surface area of wood on the front allowing it to deflect under pressure. Design flaw on me end.

I have been thinking about this all day and I had come to the conclusion that your glass had to be smaller than the front panel. Mine will be the same height as my front panel. It still has got me thinking differently about bracing the front and i appreciate any thoughts!!

 

[Leebtattoos]

That’s exactly it and my first timer mistake. Hoping my souped up exoskeleton keeps it from flexing this time around. I’m giving the silicone a a few more days to cute before I test

 

[Steve_C]

I have thought about the foam and it seems like the easier route to go, but im worred about long term with the foam. Im building this tank to hold up for a LONG time. Im never moving out of this house. So with that in mind, im gonna try to use the mortar and liverock.

No prob just a thought. Just keep in mind though if you pond armor coat the foam it will last pretty much forever. I've got ones out there that are getting pretty old and still look brand new

 

[elting44]

Subbed, looking forward to learning alot from this thread, thanks