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Comment by Jim Troyer on July 20, 2013 at 10:24am

Thanks John, great explanation.  I was surprised to hear you did not use a heat gun. 

Everything is so tight and smooth, I was sure you must have had some extra persuasion.

Once again nice job and thank you very much for the link and explanation.

All the best,

Jim  

Comment by John Doty on July 20, 2013 at 7:33am

The liner is Dura-Scrim R20WWK http://buyplasticnow.com/Products/Aquaponics.aspx This is the liner the big commercial aquaponic farms use. It's VERY strong. The link is the site the main company set up to sell smaller quantities. I think these are end runs from huge orders.
As for installing the R20WWK there used to be a Youtube of Murray Hallam installing similar liner. I can't find it any more. I think Murray has pulled it because he is now selling a CD that the footage has most likely become a part of.
The best way to describe the process is like wrapping a gift only from the inside. First, Make sure you have drilled a snug-fitting hole for the bulkhead fitting for the bell siphon. Don't cut the hole in the liner until it is fully installed.
Next I made my measurements using a tailor's measuring tape and I was very exact to not come up short (down a side, across the tank, up the other side and add enough to fold over top edge but not so much that the spring clamps won't work). After I cut what I needed I used spring clamps to hold the middle of each edge. I clamped one edge the full length. I smoothed that down to the bottom bends and made any adjustments to the clamps for evenness. When you work from the middles first and smooth towards the corners of the bottom a natural fold begins to form. I continued clamping towards the corners.
Once the edges are all clamped and the folds are pointing towards the center of the tank you will need to cut each corner once ABOVE THE TANK EDGE so you can start bending down the top excess. Try to make sure everything is pressing flat to the tank shape. Hardware stores and lumber big box stores sell aluminum upholstery tacks. That's what I used to hold the folded over top edge. Needle nose pliers helps hold the tack to start. Fold the corners back and make sure they lay flat. DON'T PUT ANY TACKS IN BELOW THE TOP EDGE or the tank will leak. Use the clamps to hold the folded corners. Bend down the edges and tack them to the top of the frame. Using an exacto knife carefully cut out the hole in the liner for the bulkhead fitting and install it.
I'll try to post some more picts. This process was difficult and exacting. The dura-scrim is quit stiff but it's so durable it's worth every penny of it's fairly high cost. Enough for all 3 4x4 foot beds was $75 but the shipping was another $70.
Hope this helps :-bd

Comment by Jim Troyer on July 19, 2013 at 12:55am

Hi John

Can you describe the method you used for putting down that liner.  You did an awesome job BTW

What brand liner is it and where did you get it?

thanks

Jim

Comment by John Doty on July 18, 2013 at 10:28pm

I'm using half-inch lava rock in two of the grow beds and Hydroton (Plant-it) in one. The plants seem to grow about the same in each media. The lava rock keeps the plants from blowing over in high winds and I use the Hydroton for root crops and lettuce.

Comment by Troy Curtin on July 16, 2013 at 1:57pm

nice job installing the lining.  what kind of media are you using?