470 gallon plywood tank build (in progress with photos)

Scott H

HI all, welcome to my plywood tank build!

Here's the background story,
I'd been looking for a larger tank (around 180gal) for a while and and the problem is that tanks that size and above are very expensive in my area and always come in a package including a stand and hood. So I started to look at building it myself, I called various glass suppliers and they were still expensive. I did a bit of research and found a video on YouTube of a guy who built very big tank out of plywood with the front panel having a cut out for a glass window and the whole inside was sealed with liquid rubber creating a water proof barrier that lasts years and years.

So theoretically you could build a tank of any size, shape or capacity out of any materiel as long as the walls were strong enough to take the pressure and the liquid rubber is applied properly.

I did a few designs and looked at cost v size ratio and decided if I was going diy plywood then I was going to go BIG.
my new tank will be 3'x3'x7'.

So fast forward to today and I went out and bought four sheets of 3/4inch structural ply and slapped this up,
2012-09-07 01.03.38.jpg2012-09-07 01.04.28.jpg

The measuring tape in the corner has about a foot sticking out. all the inside seams will be braced heavily ( I'll probably do this tomorrow) with pine studs cut to fit glued and screwed once the glue dries I'll be onto rubber!!
the glass comes last unfortunately.
 

oscarsbud

WOW ! Can't wait to see how this progresses. Lots and lots of pictures as you go along, please.
 

aquatic

I look forward to seeing you make this!

One question, not sure if you can answer though, but why do all plywood tanks only seem to have glass on the front? Why not on the sides as well? Is it purely due to the water pressure? I ask because often on my 55 I enjoy taking peaks in from the sides of the tank as well.
 

aylad

Jumping ahead a bit, what do you plan to do with this tank?
 

kb9plc

That is a awesome idea! Liquid rubber, eh? I will have to put that into my mental notes for future use

I look forward to seeing more pictures!!!!
 

Akari_32

Wow that's so cool! How much do you have invested so far, and how does it compare to buying a glass tank?
 

Scott H

wow that's a lot of quick reply's!

The no side window thing is simply a glass cost issue but could be done easily.

As to what's going in it I think I'm going to go MalawI cichlids.

It's looking like it's going to cost about $1.50 per gallon which is half to a third of the cost of tanks in my area.
 

Akari_32

Wow, that's a great price! And its rewarding to build something and see it in action when it's all done

What sort of filtration do you have lined up for this tank? A DIY sump would be nice, or a couple canisters.
 

Cichlidnut

I have a tank like this, didn't build it myself but it seems to work just fine. My plywood is sealed with fiberglass. Mine is a 125g. I'm pretty happy with it. If you have the know how, I think it's a great alternative to all glass or acrylic. So much cheaper!!
 
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frogbreeder

Wow, is that ever cool! I've seen large tanks built by fish breeders out of plywood and lined with rubber pond liner, but never ones with a glass front, before. Do you use a roller to apply the liquid rubber to the plywood? Are the joints still sealed with silicon sealant, or do you use liquid rubber for the joints, too? Can't wait to see the finished product. What a great idea! Please, keep us updated on your progress. - frogbreeder
 

Akari_32

Wow, is that ever cool! I've seen large tanks built by fish breeders out of plywood and lined with rubber pond liner, but never ones with a glass front, before. Do you use a roller to apply the liquid rubber to the plywood? Are the joints still sealed with silicon sealant, or do you use liquid rubber for the joints, too? Can't wait to see the finished product. What a great idea! Please, keep us updated on your progress. - frogbreeder

The rubber is sprayed on, I beleive.
 

Scott H

Thanks again for the replies! I'm so glad I took the time to post this up!

For the filtration I'm going to use a sump with custom overflows.

Cichlidnut I actual seen your video when I did my research! Looks awesome btw.

All the joints are reinforced, glued with wood glue then screwed together then the rubber will coat the whole lot so there's no need for silicone in the corners.

The rubber that I'm getting can be applied with a brush or roller but I don't know about spaying. some spray nozzles require the paint to be thinned which I don't want to do.

I'll be doing the braces later today so stay tuned for more photos!
 

Cichlidnut

I'd brush it on. That will allow you to get good coverage in seams. I look forward to seeing the finished product
 

Scott H

All my braces cut to length
2012-09-07 12.07.40.jpg
Test fit
2012-09-07 12.05.17.jpg
Gluing and screwing
2012-09-07 14.02.39.jpg
Close up of the front corner with the wood glue/gap filler
2012-09-07 14.02.57.jpg
once the glue dries for a day or two then I can sand it down and prep for the rubber!
 

pkeeves

that's going to be an epic tank once its up and running. congrats on the build, its looking good so far.
what are you going to do for a background? custom 3D one or something simpler?
 

aquatic

Do you already have a stand built for the tank?
 

Scott H

pkeeves, I've never liked 3d backgrounds so I won't be doing that, don't really know what I'm going to do yet...

aquatic, no, the stand is yet to be built... because I have to take out most of the wall between my office and dinning room so I've got somewhere to put it...

The build is progressing, it's just taking a little longer than I thought to do the "glue and screw" part.
sorry no new photo's yet:-\
 

LE0

does anyone know if you could do a tank like this for SW? now I have seen yours I'm really jealous
 

pkeeves

ye that's fair enough, I was just wondering because I remember watching a video on youtube of a tank similar to yours and it had a pretty cool background, 3D and the guy built all his piping into it. your gonna need a lot of filtration!
 

Aquarist

Good morning,

It looks like you are making some great progress. I have to question though, is it 470 gallons or 470 liters?

Actual size is hard to determine in photos.

Great job!

Ken
 

Scott H

LEO, you definitely can make these tanks for Saltwater there a couple of them on youtube set up for SW. You just have to make sure to get the right rubber, fiberglass resin or epoxy. make sure it's for UV resistant and suitable for potable water or a proper pond liner.

pkeeves, I've got two sumps a 40gal and a 55gal so hopefully that will be enough!

aquarist48, it's 470 gallon/1780 litres. It's guna be a biggen.
 

Aquarist

Yeah! I'm looking forward to seeing more of your progress!

Thanks for letting me know.

Ken
 

Scott H

Just finished the top bracing and took a couple snaps for you guys.
2012-09-08 19.12.57.jpg2012-09-08 19.13.14.jpg
 

midnamoondog

Wow, this leaves me speechless! I can't wait to show my husband this!
 

dsmbuddy

Subscribed! I have been debating building a tank into the wall of the basement between 2 rooms, this seems like another method I need to consider!
 

APColorado

I'm so jealous of this tank, can't wait until the finish product. This is going to be epic!!!
 

Tigress Hill

WOW, so cool!
 

Disc61

Wow, why am I all the sudden considering a DIY tank project. thanks a lot Scott, haha.
congrats on the build, look forward to watching it progress.
 

Tigress Hill

Wow, why am I all the sudden considering a DIY tank project. thanks a lot Scott, haha.
I am doing the same
 

Scott H

Hay now come on it's not my fault DIYing is awesome!
 

Disc61

Hay now come on it's not my fault DIYing is awesome!
even more awesome when your able to spend other peoples money
just walk away I say, but I can't..
 

frogbreeder

I agree, DIYing is awesome. Although it's a lot more work than just buying a tank, it's so much less expensive and more satisfying in the long run. Looks like it's progressing nicely. It will definitely be much easier than a glass tank to install sump equipment, etc. You won't have to worry about it cracking, when you try to drill. Please keep us up-dated on your progress. Can't wait to see the finished product. Great job! - frogbreeder
 

Scott H

frogbreeder, It's definitely more satisfying to see something you've built come together instead of buying. for the sump though I won't be drilling the tank, I'll be using siphon type overflows that I designed. I've never liked over flow bulkheads because they can't be moved to change the water level.

I've got a couple of photos of the rubbers 1st coat if you all want a look.

2012-09-10 21.47.20.jpg2012-09-10 21.47.53.jpg2012-09-10 21.49.05.jpg

I'm finished with the rubber now (4 coats) and am waiting for it to dry properly. (the bucket says to fully cure for potable water it can take up to three weeks!)
Am focusing on getting the glass now and can't decide on which I should get, standard 12mm float glass or
10mm toughened glass...
 

Cichlidnut

I'd go for tempered glass. What brand of rubber did you use? That looks pretty darn good. I'm going to have to try this
 

Akari_32

Wow, it looks great!

Dang, 3 weeks??
 

APColorado

Wow...coming along great.

This is definitely on my "to do list" one day when I have the space. Thanks for posting your journey.
 

Akari_32

Mine too, Amazon! I love projects like this!
 

kb9plc

I wonder how much begging I'd have to do to put this on my husband's to do list
You know… happy wife, happy life? Hahaha

This looks awesome!
 

Scott H

Cichlidnut, this is the rubber, I got it from Bunnings. I don't know if you guys have Bunnings in the US?
2012-09-12 14.24.56.jpg2012-09-12 14.25.09.jpg
Thanks for all your support guys! I'm loving this project.
 

kb9plc

Does that stuff have a.... well...... reliability life span? Essentially, at what point do you have to be concerned with it not retaining the water as it should, anymore? (if at all)
Just curious!
 

Lupinus

Will the final color be the black or do you do another step over that for another color?
 

Mer-max

I'm wanting to attempt a saltwater DIY much like this for my daughters room. This is freaking awesome
 

Scott H

kb9plc, If I remember right the guy at the shop said that its guaranteed for ten years if I follow the instructions to the letter. the instructions said two coats and I did four so I'm hoping it will last a good long time!

Lupinus, there were other coulors there (blue, sandstone etc.)but they were more expensive so I'm going to leave it black.

Mer-max, It's a great idea if you've got the know how, you can sit back at the end of the day and say "I built that, I didn't buy it, I built it" It's a very manly sort of pride really, lol.
 

kb9plc

That's awesome. A huge 10 year tank for a fraction of the cost of buying one. And you could technically make it any shape and size you need.
I am so putting this on the future honey-do list. He likes woodworking.
He's not a fish person (yet), but by the time he puts two and two together as to why I'm having him build a big plywood box........ it'll be too late; I'll have the first rubber coat on in record time. Hahahahaha

I can't wait to see what you do with this tank!
BTW, where is it going? And on what?
I assume it's either occupying an entire wall with a really strong stand, or you are building it into a wall?
 

Scott H

kb9plc, I'm going to go either malawI cichlids or a community tank. Not sure which yet. I still haven't built the stand yet because I want to water test the tank outside first. The tank is going in the wall between my dining room and office which means I've got to tear down the wall before set it all up properly, also I'm going to have to check under the floor to make sure it can take the weight... Still a long way to go yet...

I've got some good news though, I talked to a friend of mine who works at a local quarry and he's going to get me a heap of stone for the tank for next to nothing!!!
 

kb9plc

Holy cannoli, that's a lot of work!
Worth it
But a lot of work!
And those fish are gunna love you forever.
Hey, how about you hop on a 16 hour flight, come to Chicago, and build one for me when you are done. I got just the wall for you to tear apart!
 

frogbreeder

Wow, that is downright awesome! Sure wish I knew about that liquid rubber stuff when my garden pond started to leak. It definitely would have saved me a whole lot of work. Tank looks great. Can't wait to see more.
 

Scott H

kb9plc, sure I'll come to Chicago and build you a tank! as long as you can afford my flight, accommodation, travel insurance, building materials and tools... I await your response eagerly!
 

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