Why honeycomb is light without being soft

The trick is putting material where it actually does work.

In bending, a solid plate resists load mostly through its outer surfaces — one in tension, one in compression. Hollow out the middle, replace it with a thin honeycomb web, and the volume of solid material often drops to 1–3% of the total.

 Weight collapses; stiffness does not. The core carries shear and holds the two facers apart, turning the whole panel into a continuous field of I-beams.

The closed hexagonal cells also trap air in thousands of isolated pockets, so air cannot circulate. Two bonuses come free: sound is damped (acoustic insulation) and heat transfer is blocked (thermal insulation). And when the core is

 compressed, the cell walls buckle in a controlled way — that is where the impact energy goes.

Polypropylene brings its own baseline. Water absorption is negligible (below 0.01% for the raw resin, typically under 0.4% for the finished panel), and it shrugs off acids, alkalis and salts. Compared with plywood, that removes an entire

 category of failure modes: rot, mould, insect infestation, and mandatory fumigation on export.

Polypropylene brings its own baseline. Water absorption is negligible (below 0.01% for the raw resin, typically under 0.4% for the finished panel), and it shrugs off acids, alkalis and salts. Compared with plywood, that removes an entire

 category of failure modes: rot, mould, insect infestation, and mandatory fumigation on export.