My 3665 Gallon Lined Plywood Tank Build Log

[Nolapete]

Ok, here's step by step. Ignore the cuts in the corner. Paper doesn't give any like the liner will in the corners when folded down. There WON'T be any cuts in the liner.

Here's the picture progression:

Liner flat

Long sides folded up

Short sides folded up (notice the triangle formed on each corner)

The difference between corners folded inside (top/normal) and outside (bottom/my way)

Another example of the folded inside normal way on the bottom

The folds on the outside my way between inside of tank and plywood

Clean inside lines with top folded down over the 6" walls of the tank. Notice how the fold is secured in the corners. No folds on the back and front.

 

[Nolapete]

:iagree:....and this is gonna be awesome. I'm only 200 miles away from you, How much you gonna charge me to come see it opcorn:

ONE BEELYON DOLLAHS!

 

[Sploke]

I agree that the water pressure will hold the liner mostly flat, but certainly not to a water-tight degree. I think you'll get water back behind the folds where noted below, which just seems like a great area for all sorts of crap to settle.

 

[Nolapete]

I don't think it will because the overlap (secured with a 2x6 like a sandwich) secures the top against the plywood and the bottom is held in place by the bottom of the liner. As I'm filling it, I'll be pushing the water and air out from behind it.

If the liner is folded to the inside like most people do, like my friend did, it will definitely allow fish, water, waste, etc. behind it.

Of course, it's just a theory. Application is the true test.

I may use a strip of the Firestone QuickSeam on top of where the corner folds meet. It would prevent what you're thinking will happen and serve no structural integrity purpose whatsoever. Unlike when I was planning on seaming the corners.

I don't think it will be needed though and will try it first without it.

 

[alleykat0498]

Thats exactly how we fold them in square or rectangular shower's. The biggest concern we have as well as you should is the height of the "flaps" and it seems you've got that well figured.

 

[Nolapete]

The liner calculators say to use 20x25 and I calculated 20x24 which allows for 12" overlap; 6" more than I need. I'm sure the 20x25 suggested is because that is a standard size.

I don't understand why no one, at least that I've seen, draws from plumbers' experience. Everyone I've seen with ponds have always had the excess inside the pond. I think this could be adapted to almost any shape pond/tank.

 

[Phatboydime]

Have you thought about a marine grade epoxy for the inside instead of the liner. Dunno of that would be more cost effective for you?

 

[Nolapete]

Pond armor is what you would use for epoxy. Marine grade isn't potable or fish safe. VLDesign is doing pond armor in his 1500 gallon tank.

Comparison:

He spent $700 for 2 gallons of Pond Armor and still isn't done. (My tank is over twice the size of his)

The liner I need is 20x25 and even at 60 mil it's under $400 shipped. If I go 45 mil, which is all I really need, it'll be under $300.

 

[Sploke]

The problem with ponds is that they very rarely have nice square corners and straight, flat edges. I know when I did mine, due to the shape, it was necessary to have many smaller folds to fit the contour rather than 4 large ones. The smaller ones are much more difficult to keep folded down flat...pond liner doesn't crease like paper. Think of it as folding a bicycle tire....you can fold it in half, but its going to want to unfold it as soon as the pressure is off.

 

[DrNo]

This is going to be epic Nola.

Question for you and those with monster tanks in general re: access. What happens when you need to service areas that are central tank? Don waders and walk in? I'm assuming its essentially the same as an above ground pond.