Polyurethane Foam or PU:

polyurethane foam is the foam of the traditional fiberglass surfboard. This type of surfboard foam is manufacture by plastics manufacturers such as Burford Plastics. The Blank is hand shaped or CNC machine shaped out of a rough blank with a hard outer crust. The foam blank strengthened longditudinally with a timber Stringer. Once shaped to the desired form the foam core is laid up with weighted fiberglass cloth and laminated with either polyester or epoxy resin to form your surfboard.

Expanded Polystyrene Foam or EPS:

The EPS is beaded foam and the foam is similar to the styrofoam or "coolite" your "Esky" was made from. Since the foam maintains a structure based on an open cell it will absorb water like a sponge if exposed to water. Some limitations are the poor strength, low resistance to compression, and difficulty of shaping due to the small round spheres. If you are buying a low end epoxy board you can basically count on it to be expanded polystyrene in the core. This type of foam requires laminating with epoxy resin.

Extruded Polystyrene Core Foam:

This is a closed cell core and since it is “closed” it repels water and is more resistant to compression and damage. One of the most notable differences from the Expanded Styrene Cores is the flex patterns are greatly enhanced due to its closed cell structure which will allow for greater response under pressure. All your higher end epoxy boards utilize this type of construction. This type of foam requires laminating with epoxy resin. XTR is a high quality form of this type of closed cell foam.

Woven Fiberglass Cloth:

Fiberglass matt comes in different grades which is described as weight in ounces. The higher the weight of cloth the stronger the board but this also increases the weight of the board not so much from the actual weight of the cloth but the weight of the resin which binds the cloth to the foam forming the hard shell you find on the outside of the finished surfboard. Generally a board will have two layers on the top deck and one on the bottom. The deck requires more cloth to limit the damage from the surfers feet, knees, elbows head etc...

Kevlar Reinforcing:

Kevlar is the DuPont Company's registered trademark for a very light, very strong synthetic fiber. Kevlar has been used for high stress applications in many fields and was first introduced into surfing with the advent of tow surfing. Due to the thickness of the kevlar cloth more resin is required than a conventional fireglass which means an increase in the weight of the board. A comprimize can be made and only use the kevlar in high stress areas such as on the foot pads of the surfboard.

Polyester Resins:

Polyester Resins are styrene based products used in surfboard and general fibreglass construction. Commonly referred to as fiberglass resin or boat resin. Polyester Resin is an economical alternative to using epoxy resins. Polyester resins must be used when using Polyurethane Foam.

 

Epoxy Resins:

Epoxy Resins are a two-part resin system used for low shrinkage, low brittleness high strength applications. Epoxy Resin will outperform most polyester resins but it is a more expensive alternative. Epoxy Resins must be used when using Polyester Foam.