Creating hollow metal sculptures is a popular method for reducing weight while maintaining structural integrity and artistic appeal. Here are the most common techniques used by artists and fabricators:

1. Sheet Metal Fabrication: Artists shape thin sheets of metal into hollow forms by cutting, bending, and welding. This method allows for intricate designs while keeping the sculpture lightweight.

2. Lost-Wax Casting with Hollow Cores: Traditional casting techniques are adapted by leaving hollow cavities inside the sculpture, significantly reducing material usage and weight.

3. Wireframe Armatures with Metal Skin: A lightweight wireframe serves as the skeleton, covered with thin metal sheets or mesh to create the outer surface.

4. Modular Construction: Sculptures are built in separate hollow sections and assembled, distributing weight evenly and simplifying transportation.

5. Internal Support Structures: Strategically placed ribs or trusses inside hollow sculptures provide strength without adding excessive weight.

6. Perforated Metal Techniques: Cutting patterns or holes into metal surfaces reduces weight while adding visual texture and interest.

7. Inflatable Metal Concepts: Some contemporary artists use specialized techniques to create semi-hollow metal forms that appear solid but contain air pockets.

Each technique offers unique advantages depending on the sculpture's size, design complexity, and intended display environment. Modern artists often combine multiple methods to achieve optimal weight reduction while preserving artistic vision and durability. The choice of method depends on factors like metal type, structural requirements, and the desired aesthetic effect. These approaches continue to evolve with advancements in metalworking technology and materials science.