"PVC sky balloon"? It could refer to several things, depending on context:

1. PVC Helium Balloon A large balloon made of PVC (polyvinyl chloride) used to float in the sky, often for events, advertising, or scientific purposes.

2. Weather Balloon Some high-altitude balloons are made with PVC or similar materials, used for atmospheric data collection.

3. Decorative Sky Balloon Balloons used in outdoor decorations for parties or events, made from PVC for durability.

4. Hot Air Balloon (PVC) Though most hot air balloons use nylon, there might be experimental or small-scale versions using PVC.

5. Sky Lanterns or Blimps Sometimes people call large inflatable advertising blimps or sky lanterns sky balloons, and some are made from PVC.

Let me know the exact use case or what you're trying to find outsuch as size, purpose, lifting capacity, or how to build oneand Ill give you a more tailored answer.