How Neoprene Works: Behind the Scenes at Mormaii
Murillo Caldas explains the physics of thermal insulation in water and local manufacturing in Garopaba.
Learn how neoprene provides thermal insulation in the water through microscopic air bubbles. Murillo Caldas details the precision cutting process, the physics of compression under pressure, and why Mormaii maintains its factory in Garopaba.
Many people put on a wetsuit to swim, surf, or dive without realizing the physics and engineering behind the material. The neoprene manufacturing process begins with thick sheets of raw rubber that are sliced with millimeter precision to meet the demands of each sport—ranging from thin 1 mm to 2 mm sheets up to dense 7 mm or 9 mm slabs used in heavy-duty operations like underwater mining.
The physics of thermal insulation and water pressure
There is a common myth that wetsuits actively heat the body. In reality, neoprene does not generate heat: thermal insulation is provided by air trapped inside microscopic bubbles within the rubber structure, which blocks heat transfer with the surrounding environment. In conventional designs, a thin layer of water enters the suit, stabilizes, and is kept warm by the athlete's own body heat.
The rubber formulation changes drastically depending on the discipline. While surfing and swimming prioritize flexibility and stretch, diving demands far more durable rubber compounds. At a depth of 30 meters, for example, the body and the suit experience roughly four atmospheres of pressure. Under this force, the microbubbles undergo severe compression, and an improper neoprene blend loses its ability to expand and insulate once back at the surface.
In-house production in Garopaba and real-world development
While much of the global market relies on private labeling—picking off-the-shelf items from Asian factory catalogs simply to apply logos—Mormaii maintains its manufacturing in Garopaba, Santa Catarina, where it has operated since 1979. The historic decision to keep the factory in Brazil, upheld by founder Morongo, aims to secure local economic impact and jobs while ensuring direct control over pattern design and stitching.
In the industrial routine, a complete batch takes between 10 and 15 days from raw material to finished wetsuit. This direct factory control allows Mormaii to test prototypes in the water, fine-tune seam junctions, and validate dry or athletic designs before they reach athletes, ensuring that cutting-edge patterns evolve according to the real-world demands of those in the water.