EPVC Capabilities

EPVC Capabilities for Bucky Domes

By: Josh Rucinski

      As part of a project in creating a buckydome that is at least half scale, there has been a drive to create the dome as inexpensively as possible.  A major crux of the whole endeavor has been the materiality of the connector pieces.  Metal is expensive and difficult to fabricate.  Wood is inexpensive, easy to fabricate, but it is weak when subjected to cross grain stresses.  The connectors would have a lot of cross grain stresses due to the geometry of the connector piece. 

      The image shows the basic connector piece form.  Since there would be so much machining to make this out of wood, the basic shape, which is only about 6 inches in diameter would lose integrity.  Therefore, a new material has to be introduced.  Web searches for a material that would be easy to machine, strong enough to function as intended and be reasonably cost effective.

      Expanded Polyvinyl Chloride is that material.  It is a plastic, and has a cellular 'foamed' nature, so it is less brittle than solid PVC and lighter too.  Unlike a lot of other plastic choices, it will not melt when machined, so the edges will stay crisp.

      EPVC is used largely in the sign industry as a substrate for silk screen printing because of its superior dimensional stability as opposed to wood, and it's weathering characteristic are also superior in regards to water and wind.  The Sun's UV light can destroy the plastic over time, this has been somewhat mitigated with admixtures allowing a six-fold increase in UV durability.  Durability can be increased with coatings and this might be explored further as the project matures.