EVA Manufacturing

[Len]

I'm confused! You ask about EVA, but the machine to which you refer uses EPS.

Expanded Polystyrene (EPS) and Ethylene Vinyl Acetate (EVA) are very different materials and may require different process strategies.

Fishing floats made w/ EPS can be molded by loading a pelletized PS which contains an enclosed/bound volatile liquid material w/in the solid pellet. The mold is closed on a charge of pellets and then heated to a point where the volatile liquid w/in the pellet is converted to a gas, thus expanding the pellets. The pellets expand and pack together, filling the cavity. After cooling the EPS conforms to the shape of the mold.

EVA may be foamed, but this is usually done by incorporating a blowing agent during the extrusion or injection molding process. Heat of processing activates the blowing agent and causes the EVA to expand.

What is your question really about?

Len

[Louis]

I'm thinking it is blown into a mold that gives it the outer surface texture. That is if indeed it is a hollow air filled sphere of EVA.

How thick are the walls?

[Len]

I could be wrong, but arn't those "water weenie" kid toys made of foamed EVA? I think they are foamed via a blowing agent during the tube extrusion process and thus are closed cell foam core tubing w/ a smooth outer skin. You could slice these into chunks and have floats like those used for nets and mooring lines. Just my thoughts.

Len