Thinking about plywood tank again...

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Conner

Conner

Piranha
MFK Member
Dec 27, 2008
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Kentucky
:nilly:

So, I've been thinking that I should build a plywood tank again. The reason is that I'm getting more and more into rays, and I have several gar as well. I need a wiiiiide tank, which I just haven't been able to find many of for a decent price lately.

After designing it out, I figured I can probably do a 250g, 78"x36"x24" (LxWxH) tank for $220, depending on what plywood I choose. Here's how:

I have a 55g tank that I'm considering breaking down anyways, so if I use the front and both sides from that, I will have 3 viewing windows covering just over 6' in length (hence the 6.5' tank length). I will just make the tank tall enough to accommodate the height of the glass, and then I can make it 3' front to back, so I can keep rays for a long long time in it. I'm also thinking of using a 45 mil epdm liner, as they are cheap, tough, and (relatively) easy to use.

Here's the cost breakdown so far (tank only):
Glass = 55g tank glass = $0
Plywood = (3x) 0.75"x4'x8' = $120
Screws = $0 (have plenty)
Liner = 45 mil epdm 10'x15' = $77
Silicone = 5 tubes (?) = $20
Total = $217

So that's building the actual tank, waterproofed and fish ready, for $0.87 a gallon. Not bad. Only gets more expensive once I add a stand, sump, filter media, heaters, and pumps.

Does anyone see any problems so far with the tank?

Here is a pic that shows the tank from the front.

250g plywood tank.JPG
 

Attachments

The viewable portion of the windows will be this:

9"x18" for the two small windows
45"x18" for the large window
 
how thick is the glass on that 50 gallon and tearing down a tank is tedious risky buisness.

i just tore down a tank and broke the two sides.
 
bigbaddad;3856693; said:
how thick is the glass on that 50 gallon and tearing down a tank is tedious risky buisness.

i just tore down a tank and broke the two sides.
Click to expand...


I'll have to double check when I get home, but it should be 3/8", which according to garf.org will work for the size tank I listed above.

Well, if I end up breaking the glass, I can always go out and buy some new glass, and then I can have one window instead of three. But if I can use the glass from the 55g, then I will.

I do have 2 125g tanks I could use, but I'd rather not sacrifice them.
 
Check out my 90 Gallon Expansion thread. You could make an 8' tank and put the smaller pieces of glass long ways and the 4' glass in the middle.

BTW, tearing apart a tank is tedious, but easy. You just have to take your time, be patient, wear gloves, and think. Broken glass is unnecessary and rare. There's only two reasons for that to happen; the glass already had a fracture or carelessness. I've dismantled, resealed, and refurbished many tanks and have never broken a piece of glass.

You can build the same height tank with any given piece of glass. If you're skeptical, Google hydrostatic paradox.

wintank.JPG
 
I think I'd rather actually just have a 6.5-7 foot tank, as space is an issue. Besides, depth (front to back) is more important to me than extra length.

I just measured the 55g glass, and its a hair under 1/4". Not as thick as I thought. Will that thickness still be ok for a 24" tank (probably on 21-22" water depth)?
 
I'm gonna call tomorrow and get a quote for some 3/8" and 1/2" glass sizes. Here are what I'm going to price:

94" x 22"
82" x 22"
70" x 22"

After I get those quotes, I'll check craigslist, cuz there's been a lot of tanks up for sale lately, and I think I saw a 125g for $150...
 
I got glass quotes today for 3/8" glass with polished edges. Sizes and prices:

94"x22" = $143.60
82"x22" = $125.30
70"x22" = $106.90

These were cheaper than I was expecting. I found a 125g tank for sale on craigslist for $150, but for $7 less I wouldn't have to deal with taking it apart, plus I'd get a new, clean, polished piece of glass that was 2 feet longer...

At this point I'm considering whether to make it 6' long or 8' long. Cost won't really be increased that much for the extra 2 feet. Figure $37 more for glass, plus $12 more for the pond liner, and that's about it. I would still be able to get the tank out of 3 pieces of plywood either way, and since I already have all the screws I need, that won't be any more costly.

SO for an extra $49, would you go 8' instead of 6' (rhetorical question :screwy:).

Looks like if I do this build, it will be 96"x36"x24", single viewing window, and 45mil epdm liner.
 
Glass thickness is determined by height, so if you build a tank the same height you can use the same glass as the 55.

http://scubageek.com/articles/wwwparad.html

If you decide to go with a liner, check out my liner folding technique in the beginning of my big thread.

Also, you want to use a hard rubber gasket (you can buy the material from a rubber supply house) and rubber cement it to the liner. Then use Dow 795 to attach the glass to the rubber gasket.

My friend has 2 tanks built like this with 3 6' windows each. 2600 and 2200 I think the capacity on the narrower tank is. 26' long and 36" tall. The 2600 is I believe 48" wide.

I can give you details to the process when you're ready, but basically, you fit and fill the tank with the liner in it to get it situated. Drain and dry the tank. Install the gasket on the liner, attach the glass to the gasket, put braces behind the glass to hold in place, let it cure, refill the tank to test the fit. If everything is good, you cut out the liner section to expose the window.
 
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