The Build Pt 2
With the epoxy paint dry, I added casters and righted the assembly. Next came the doors. With the doors added, the additional stress on the walls to support the doors was enough to bend the walls slightly and prevent the doors from aligning. So I added a 1"x4" clear acrylic crossbeam to the top of the terrarium to prevent the deformation.
With the crossbeam in place, the doors matched up nearly perfectly. However, I live in earthquake country - and large plate-glass doors shouldn't actually meet directly at all - so I added a clear polycarbonate edging to the doors which both protects the edges of the glass and is flexible enough to be shimmed into a perfect seal between the doors.
The bottom of the terrarium needed to be something of a basin to collect the water run-off. I drilled and epoxied a drain hole and then used a 3/8" thick sheet of polycarbonate to create a curved bulkhead matching the doors. With clamps I was able to match the bulkhead to within 1/8" of perfectly aligned with the doors. More epoxy sealed the polycarbonate wall in place and added another layer of waterproofing to the already well-sealed bottom. Here again, strategic placement of the polycarbonate edging gave a perfect seal with the bulkhead and glass doors (my obsession over perfect seals is quite unneeded for orchids... this extra work is in the interest of containing frog prey).
With the bottom and the rest of the interior fully sealed, I paused in the work to consider the proper interior assembly. The aforementioned orchid terrarium was built using real wood - I was lucky enough to find a gorgeous knarled and contorted madrone trunk on the roadside that I was able to cut and stack into a great base for orchids. The problem with the scale of my new tank was that using wood for my intended design would have added 500lbs to the weight of the viv. In addition, the constant moisture would begin to structurally weaken the entire setup with a few years.
In a departure from my previous terrarium construction, I decided the interior would be of all artificial materials - items that would not rot or disintegrate in constant moisture. I did a bit of DB lurking to confirm that styrofoam was a durable choice (I had already used some, hidden in the orchid terrarium, for supporting the stacked wood).
For those needing terrascaping-grade styrofoam in unlimited amounts at a very good price, look no further than solid home insulation panels. They can be had at home depot or lowes for ~$20 per 4' x 8' panel. I brought one home and began sculpting and stacking. The intent was to create a giant tree trunk that would coil around the interior of the terrarium and then spread into branches.
A few rounds of gluing, waiting and more stacking and I had built-up a nice trunk shaped structure of terrace-stacked styrofoam pieces. With the backbone done, I needed to smooth this very artificial looking structure into more of a naturalistic form. I started with spray foam but realized quickly it was only good for filling irregular voids - not so much for creating a smooth surface.
The breakthrough came when I visited the local plastic supply store and saw huge bags of styrofoam pearls. With a proper adhesive, these pearls could be mixed into a modeling material and spread/sculpted into place. Using the remaining epoxy as a binding agent turned out to be a good idea. 4 tablespoons of epoxy was enough to create a gallon of molding pearls when mixed. The initial mixture was a little too "runny" and did not stick to vertical surfaces very well - though it did handle horizonal mounding just fine. By adding a thickener to the epoxy, I was able to add just enough stiffness to the pearl mix.
The resulting material was lightweight, quick to dry, easy to apply to vertical surfaces and, when cured, was firm and strong. I discovered that a paper towel was a perfect appliance tool - it was like a non-stick surface that could be used to manipulate, place and sculpt the pearl paste (a material which otherwise stuck to gloves and any other object with the slightest contact). The paper towel method allowed me to sculpt a wonderful smooth surface of pearls to cover the angular tree layers.
Once complete, I had a nearly 7 ft x 2" tree trunk that weight about 15 lbs. Even better, this material would never rot and was still strong enough to support a person. As pleased as I was with the shape of my tree, the white color of the tree and the baby-blue of the walls (the color of the epoxy paint) was not so natural. I'll save the discussion of surface covering for the next installment...
Last edited by kimcmich; 03-12-2016 at 07:31 AM.
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