If Your First Plywood Tank Fails, Make It Bigger and Try Again - 650 Gallon Build

As the title states, my first tank build did not end up holding up, here is the link to my old 400 gallon build.

400 Gallon Build

So the interior dimensions of the new tank are 86"x48"x35" making it just under 650 gallons. Figure the key to success must be to make it bigger so tacked on another 250 gallons over the last build. Doing things 100% different this time and trying to do it cheaper and much faster. In this build I will not only do a price list, but also a time list to track hours on the build.

This tank will be framed with 2x4's just as you would a wall and the front will be the same as the 400 gallon with a 3/4" plywood front with the viewing window hole cut out. 1/2" plywood will be screwed to the framing. Not going to mess around with liquid rubbers, epoxies or fiberglass, going to use pond liner. The only tricky part of this build will be to get the viewing window in properly with the pond liner. I have seen success in doing this before so I'm hoping it won't be too difficult.

Costs
(15) 2x4 - 10' - $25.79
(15) 2x4 - 8' - $20.85
(3) 1/2" Spruce 4x8 Plywood - $55.50
Screws - $5.50

Total - $107.64

Hoping to salvage the glass from the 400 gallon so I won't have that $200 expense this time. Only other costs I'm hoping to have is around $150 for my pond liner. Goal for the build is under $250.

Time Spent
April 13th, 2012 - 2 hours
April 14th, 2012 - 45 minutes

Total Time - 2 hours 45 minutes

Time is money, so figure that the amount of hours spent on a build is equally as important as material costs. Time goal for this project is going to be 5 hours (from start until it is full of water not leaking).



Here is where the tank sits now, all that remains is to screw the plywood onto the sides, cut the front panel for the viewing window and put in the liner. Things will be at a stand still until I get the 400 gallon torn down and the glass removed.

Any advice/experiences with pond liner and the viewing window would be much appreciated.

Thanks, but this one will be just as beautiful, but bigger! Ya, that's what I figure, less things to go wrong using the pong liner. Yes, I have a plan, hard to explain, but I'll do the best I can. My glass is 78"x31", so I will cut my viewing window hole out of the plywood all about 1.5" overlap on all sides. I will lay out the pond liner and carefully cut the hole where the glass goes. If my window opening is 75"x28", I will cut the rectangle out of the pond liner to 76"x29". I'll experiment with different adhesives to see which will bond the liner to the plywood best, and around the front window will glue/silicone the pond liner. This will leave about .5" of plywood showing on all sides. Then I will silicone in the window, this way the glass will be overlapping the pond liner, but there will still be that bare plywood for the silicone to get a good seal around the window if it doesn't adhere well to the liner. Not sure if you follow that haha, but I think I got a solid plan there.

I would epoxy the front pane, glue the window inn, then overlap the remaining epoxy with pond liner.

Click to expand...

That would be easier, but I don't think the pond liner will stick real well, I think it'll have to be held in place with the window?

Got the 400 all cut up and hauled out, worked on the glass for a bit and there is absolutely no way for me to get it off cutting it with a utility knife. Any tried methods for removing silicone? Going to go down to the store tomorrow and see if I can find some sort of silicone remover. If that fails I'll have to buy another sheet of glass.