Construction Updates 2
From Batcountry
See Construction Updates Part 1, Part 2, Part 3, Part 4, Part 5
Here we show Part 2 of our construction process for Bat Country: Generation 2
Click on photos to enlarge.
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[edit] Materials: Joining Units
After building the Gen 1 tetrahedron, we decided to change our construction method. For the Gen 1, we attached 3 bats to each joint to build Gen 0 (6 bats) tetrahedrons, then used the joining plates with the little bolts to assemble joints in pairs. Dealing with the little bolts was rather "fiddly".
For the Gen 2 construction, we instead started by assembling the pairs of joints first (with joining plate and 6 little bolts) to make double joint units. Assembling these double joints really blacken our hands. We changed bolts twice along the way so that they have a low profile and wont poke people who climb on them. The photo below shows our first version, before we flipped the bolts.
After the joint is assembled, we use an electric drill to tighten each bolt and then to clear the holes of any jagged edges. We just ordered a new drill bit to make this clearing holes easier. It's important to have smooth holes so we don't damage the threading on the rods.
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[edit] Layer 1: Building a Gen 2 Sierpinski Triangle
We want to test the strength of the Gen 2 tetrahedron that will form the top quadrant of Bat Country. So we bolted three completed joint to wood-filled cement supports for the base corners of the Gen 2 tetrahedron. When the Gen 2 is complete, it will be supported entirely by these joints on the 3 cement blocks.
We laid out an equilateral triangle with 4 bats on each side and the cement blocks at the corners. Then, we bolted the bats to completed joints. Then, we added bats to make a Gen 2 triangle, which is all of the bats in the base of the Gen 2 tetrahedron.
To help everything lie in a plane, we add supports under the joints. At this point, our additional supports are made of the finest plastic food storage containers in our collection. For Bat Country, we will use large plastic buckets to support the joints instead of our little plastic containers. This lift is necessary to provide us space for our wrenches to tighten the bolts.
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Next we add the coupling nuts, first screwed all the way onto one bat. We will center these after they are all added to the base. Once the pieces are assembled, the next step to to tighten all of the large bolts attached to the bats and the coupling nuts. For Bat Country, each coupling nut will be glued into a cored 12" softball.
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As the bolts are all tightened, the base triangle started to flatten and lift off the ground! Oh, YES! In the process of tightening, the coupling nuts are centered in each joint. Finally, the base triangle is tightened, as our dog Walter so nicely models. (Goooood doggie.) We use bricks to support the joints that will be most stressed as we build the next layers. After completing Layer 3, the structure should be quite solid. Accordingly, we should be able to remove these bricks and the structure will be fully self supporting at only the 3 base corners. How exciting!
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In terms of construction, we can tighten one new layer at a time. As we add each new layer, we must keep everything loose or we cannot fit the pieces together. When the pieces are all assembled, we tighten everything at once. Now, the bottom layer (above) is complete.
For the purpose of counting layers, the bottom layer is actually only a half layer because it can all be tightened at once. The next layer will be composed of 2 sets of bats: The bottom half layer is bats pointing up. The top half layer a plane of bats parallel to the ground, plus the new joints that will hold Layer 2 together.
[edit] Buiding Layer 2 of Gen 2 Tetrahedron
Now, the fun part... adding bats. We add 9 bats, then 6 more.
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Then add 3 more bats in the center. This finshes the bottom half of Layer 2.
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Adding the top half of Layer 2 requires some fiddling and selected untightening of Layer 1.
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[edit] Sunset
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[edit] Buiding Layer 3 of Gen 2 Tetrahedron
The first half of Layer 3 is very easy. We add 9 new bats.
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Then we add joints, which is also easy.
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As you can see in the photos, it's night time. We will have to wait for another day to finish Layer 3...
This completes Part 2 of Construction Updates.
Go on to Construction Updates 3.
All images, designs, and text on this site © 2005-2008 Gwen Fisher and/or Paul Brown. Permission required for any capture or reuse.
