HDPE Panel/Liquid Rubber/Plywood 240 Gallon DIY Aquarium Build

[coolkeith]

That Garf site is way outdated. It was popular 10+ years ago when the DIY plywood tank craze took off. There have been some successes, but there have been a lot failures following those plans also. When you plug in 25" for height, notice how it says "GARF Does not recommend building a plywood tank longer than 48 inches when the height is more than 24 inches. "

Here you're building an 8 ft tank, at the max height for those plans, using the minimum glass thickness, on a top heavy stand. You might just want to keep this tank in the garage or basement on a concrete floor, where it won't do any damage if it fails. In a living area like in the picture you provided, if you have wood floors underneath that bounce or vibrate, it could be concerning.

 

[muttley000]

The only tank I've built uses the epoxy pour method, so there is a quarter inch minimum epoxy on all surfaces, and the plywood substrate is not very important to the structural integrity of my build. I would look and do research on what the other guys are bringing up with the liquid rubber build as I don't have any experience on if it will bow and compromise the seal. I do believe your corners are only going to give once before it's over! I like the idea of the shallow tanks underneath, but they look like they will be difficult to access. You need more space above them. They will help get the center of gravity lower which is a plus on your extra tall stand. I would second fastening it to the wall, especially if you have to worry about kids hanging on it! When you test fill, please report your deflection.
Your stand looks a little beefier with the change you made, but the plywood will still be your only protection against racking, which seems like it would be a bigger problem with your height.

 

[BearFish]

Keith, I see what you mean. I might have to think about how the brace the bottom seam better. My house is on a slab floor, so it is on concrete in the picture. I would never put this on a wood floor.

 

[BearFish]

So I've got 9 coats of ames blue max on the plywood, just put a fresh coat on for 10 coats total. This stuff goes on in very thin layers. I put another coat on the HDPE panel and let the two coats set up for about 30 minutes. After that, I put the bottom HDPE panel in place. I'm hoping the ames blue max will act like an adhesive. I also did the same to the back HDPE panel today. Tomorrow I may get the other three sides.

 

[BearFish]

Muttley, How much room do you recommend? Right now I have 5 3/8" to reach down a 10" deep aquarium.

 

[BearFish]

OK, I did some plastic welding and welded HDPE strips at the seams. It is good because it stops the deflection from the sidewalls, but they are not good enough to be water tight.



So, on goes the butyl caulking. Not happy it is white, but I can hide or paint the seams later.

 

[muttley000]

Muttley, How much room do you recommend? Right now I have 5 3/8" to reach down a 10" deep aquarium.

Are you gonna have lights between there? Think of trying to net a fish or work in the tank in that space. I have a lid that is 9" above the water and a door that is 6" tall that I remove to feed and work on a 65 gallon, it is a pain in the rear!

 

[BearFish]

Well Muttley, when I started this build I knew I would have a design flaw and that would be access to the tanks.

So, any way back to the fun of building a monster fish tank.

I've got a three tier setup. 240 Gallon at the top, smaller ~100 gallon below, and a large sump ~150 gallon.




Here is the structurally enhanced version of the stand. Need to skin it, and paint it still. Used up a box of 474 screws on the tank and stand.



Glass comes in on Friday, I hope to give the main tank a water test on Monday. Wish me luck

 

[BearFish]

So getting ready for the glass. I was not able to plastic weld this 1.5" long piece that the glass will sit on like I've done with the other corners that only had 1/4" thick strips. But, I was able to tack it in place. Using butyl caulking again to make the tack weld water tight.

Here is a picture of my cheap Harbor Freight plastic welder (I paid a little over 50$ for it), and a pretty good tack weld if you ask me.

 

[BearFish]

Putting the glass in, here is my checklist:

1. Check for high spots. You can crack the glass if you put pressure at one.
2. Have double the amount of caulking you need with expectation of tanking it back to the store
3. Have a glass suction cup thingy (This work great to pull the glass too you)
4. Have enough wood pieces with soft insulation foam stuff to use as devices to put pressure on the glass (see picture)
5. Have plenty of lighting
6. Have a way to get access to the top of the tank with ease
7. Move hammers very far out of reach.


I ran a 0.5" bead of the butyl caulking around the glass, and pushed it against HDPE panel. This is how I put pressure on the glass. I hot glued the insulation pieces to the wood so they would stay place before I started. This worked out really well.



I may have used to much caulking, the sides made a tight fit. But, the center seemed to have around 1/8" gap and I could not push it any closer. I'm not sure if the tank front is warped a bit, or there was just too much caulking at this location. This picture also shows the plywood, ames blue max, HDPE Panel, Butyl caulking and glass interface well.



So, this butyl caulking seemed to creep out of the joints as time when on. I guess the pressure was causing it to push out of the seams. But, long story short, I have lots of caulking all over the place!



Lots of work, and I finally started to get it cleaned up. There is still a fogginess on the glass from smearing the butyl caulking.