Catchment cover frame DIY?

[seekir]

I made a simple PVC rig as EightFingers describes for my tank years ago: two lengths of 1" PVC pipe somewhat longer than the diameter of the tank crossing each other in an "X" shape with T's at each of the four ends where the pipes meet the pool rim. I cut about a 1" gap along the T's long side that would fit and grip the rim of the pool and used exterior-grade plastic zip ties to join the two pipes at the intersection of the X. The lengths of pipe were long enough that they bowed up a bit which lifted the cover about a foot and a half above the water. I guess a better and more rigid center could be made as a square with T's between the four elbows cut into the four sides of the square (maybe about 1' along each side?) with the four legs meeting the sides of the center square at T's in the middle of each of the square's sides. If more legs were required I suppose 45's could be used instead of elbows to make a multi-sided (octagonal?) center. I suppose the joints could be left unglued, at least until the appropriate angles for the height of the cover were determined.

[birdmove]

The PVC pipe idea is interesting. So 1" is stiff enough to support the cover, but still bendable. My tank is from 1996 and I believe it's a 15,000 gallon unit. seekir, how big is your tank? I ask because the newer tanks seem to be much smaller diameter and higher, and so the PVC pipes wouldn't have to support as heavy of a cover.

By the way, people make bows for archery out of this plastic pipe. You can find youtubes on the process. Looks pretty easy and the bows can be quite powerful.

Jon in Keaau/HPP

[seekir]

That was a 15' diameter pool tank, I suppose you could use 1.5" PVC for larger tanks (or use the alternate octagonal center structure with more legs/strength). I think I bent the pipe into place alone but I think it'd be simpler with help.

[birdmove]

Seekir, thanks for the tips. I mention above that people can make pretty powerful bows for archery with the PVC plastic tubing. They use, if I recall correctly, a length of 1/5" tubing and insert it into a length of 3/4" tubing. It's a bit tight, but that's what they do. I think the bow, depending on length, ends up around 60 pound pull. So that method could also be used if the cover was too heavy.
I haven't removed my cover since I moved in just over a year ago, but I am going to try this method as you did.
Another very helpful bit of information from Punatalk.

Jon in Keaau/HPP

[seekir]

With the center square or octagon method (which I haven't tried) I'd think the "legs" could be straight or slightly bowed up against gravity depending on the angle the "T's" attaching the legs are glued onto the center and the length of the legs. I'd think a wide tank might require an arching bend for strength to help support the cover's weight. I actually used fishing line to bow my rig's two "X" crossed PVC members (just like a bow for shooting arrows) into an arch so that the rim of the pool wouldn't have to bear all the outward pressure of the arched legs. This probably made the assembly process simpler since you won't have to flex the pipe into the arch-shape during the mounting process. I just cut saw kerfs into the modified "T" feet of the crossmembers that rest on the tank rim so that a knotted length of line could be retained like a bowstring, this made adjusting the line's length fairly simple so that the arched crossmember would be the correct length to span the tank.

[DanielP]

If you are going the PVC route, you might try schedule 80 electrical PVC conduit.

[terracore]

Is there an advantage to the cloth covers that have to be replaced every few years as opposed to a more permanent metal variety? (Other than initial cost)

[kalakoa]

I'd say "cost", after you're done barely affording the tank you don't have much left for a nice cover...

[rainyjim]

I'd like to see one of these on a catchment tank -

http://domeclimber.com/



Cheers

rainyjim