Monday, November 11, 2013

Aquaponics - PVC Cold Frame

Aside from a few hiccups the aquaponics system is coming along brilliantly, which means by this time next year I'll have torn it down and rebuilt it at least four times. The old "don't fix what ain't broke" adage never seemed to take hold with me.

However with winter just a month away, I couldn't put off building some sort of protection for it any longer. The priority for the build was cheap. Having blown the bulk of my book royalties on a used Camry, extra cash is a bit spotty right now. Fortunately for me, someone is always giving away something cool on Craigslist and as I was wasting time avoiding work taking a second to check out the ads I came across a listing I couldn't resist.

Free Bubble Wrap
6 rolls take all.

Who couldn't use bubblewrap? If nothing else it would give me hours of bubble popping pleasure! I already had a use in mind for it though.

I wrapped the fish tank with it, to serve as a bit of an insulating blanket. I also wrapped all the way around the sides of the grow beds and sumps.  That cut out square on the upper right is the water line marker. I can see it from the utility room window and tell if the water is where it's supposed to be, or if I have to make adjustments to the flow.

Then it was time to build a frame to go along the top edge. This would not only protect the upper edge of the bubble wrap but provide a base for the cold frame to sit on.

The bubble wrap looks atrocious but it does a good job of keeping the wind from getting underneath. I have some 12 ft sheets of clear poly siding that we'll slip up under the edge to give it a bit of protection, though I doubt it'll make it look any better.

Next comes the cold frame. Just 2x4s on their narrow edge.

Since the bed is just under 4' wide I picked up 1/2" PVC for the ribs. Since PVC comes in either 10' or 20' sticks, and since I have no way to transport 20' I got the 10'. Ideally I would have been able to cut the individual ribs at 6', but that would have left me with a lot of waste so I went with 5' and crossed fingers.

And, after it became obvious it wouldn't work, added a heat gun. Using the heat gun I was able to bend the ends to conform to the edges of the frame, which allowed the shorter length to work.

Each rib was screwed into place with 1/2" pipe clamps... which would have fit better had someone told me in advance that 1/2" PVC is actually 3/4" OD and therefore slightly too big for the conduit clamps I picked up. Oh well, it worked.

Once all the ribs were in place, I took the bubble wrap and cut it to match the length of the cold frame. The wrap was 2' wide by 50' long, so I laid three strips down and taped them together with commercial grade packing tape. Then we stood the frame on its side and laid the bubble wrap blanket on the one edge and gave it a temporary tape job to hold it in place. For the plastic cover, I picked up some 2 mil plastic drop cloths at Home Depot and a 1"x2" strip. We rolled the edge of the plastic around the strip twice, laid it on top of the bubble wrap, and screwed it into the frame. We then flipped the cold frame and repeated that process on the other side.

Had to do a little finagling on the ends since the drop cloth was only 12' and I really needed 14'. We took strips we'd cut off from the long edge, taped them to the short end, and then rolled and tucked the same as on the sides. Voila! Cold frame!

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