I have started with a new bronze version of Between Heaven and Earth in which the elements have a profile of a teardrop. The top picture shows the casting model made of wood by milling and sanding and below you can see the results of the first sand casting, which turned out very well. Soon I will cast another 10 of these bars which in total should be sufficient for the complete sculpture.
One side finished
The frontside of the new sculpture Plumage in Bronze has been finished: the 4 moving bars are balanced and can be moved smoothly all around and they remain steady in any of its poses. It functions wonderfully! To make the long moving bars at the right length for perfect balance was a challenge since the mass distritution of the bars is not equal along their length. It required extensive calculations.
At the moment I am constructing the other side, which is equal to the front side.
Bearings and Center of Mass
The development of the new sculpture Plumage in Bronze proceeds well. From the sprues of the bronze casting of the profiles I made bronze bearings, with axles of stainless steel.
The sculpture is now being build up step by step, this is the base with the central rotational joint. Since the moving sculpture has to be perfectly balanced in all different poses, it is important to know of each part precisely the mass and the location of the center of mass. For finding and measuring the center of mass I developed a measurement system, shown in the last photo. Here the profile is clamped in a block with a small axle. By moving the block hence and forth and up and down the point can be found in which the profile is balanced and does not turn around. The axle then is in the center of mass. The results of the measurement influence the exact lenght of the other parts, which then can be calculated.
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