Surfboard blanks

What is the difference between Polyurethane and EPS (Expanded Polystyrene) blanks?

Polyurethane blanks are molded and are the traditional blanks. Once surfboards started featuring foam centres, polyurethane foam was the most popular selection. Polyurethane foam blanks are used in conjunction with polyester reins to produce what is known as a polyester, or PU surfboard. EPS blanks are formed in billets (large rectangular cubes) the hotwired to specific rockers and thicknesses to make the surfboard blanks.

What is the difference between Polyurethane foam, Molded EPS Polystyrene and Extruded Polystyrene Foam?

Polyurethane and polystyrene foams differ in their chemical makeup. Chemical makeup aside, the three foams asked about are different in their cell structure. Both extruded polystyrene foam (XPS) and polyurethane (PU) foam are a closed cell type foam, which is made up of a suspension of tin bubbles.EPS foam consisits of smell beads of polystyrene that have been stuck together. Many are familiar with EPS foam as is commonly used for foam cups and beer coolers. PU foam can be glassed using epoxy resins and polyester resins, whereas XPS and EPS foam can only be glassed with epoxy resins. EPS and XPS resins will react with polyester resins. All foams come in different densities.
There are two different polyurethane (PU) foams to be on the lookout for, one is a tolulene-di-isocynate (TDI) base and the other is made of using methylene di isocynate (MDI), a less toxic chemical.
People buying stock boards off the rack will have more options, and might therefore be less informed of (or more confused by) the options that face them as they might not be familiar with the properties of certain cores or composite materials. A very little group of people will have an intimate knowledge of the vast array of foam cores and their composite technology, a matter that may affect any given shape-shapers that have such knowledge will be even more in demand.
Stay tuned to find out where to buy polyurethane  foam or to find a surf online store.