Shell Surface
Two major types of material are used to manufacture spa shell surfaces:
OAS and acrylic. They are both resistant to impact damage and can handle a fair
amount of rough treatment, but there are some significant differences between
them.
• OAS. Olefin Acrylonitrile-Styrene (OAS) is used for shell surfaces
under several different names. Two examples are Rovel and Ultralife, but all OAS
shells are made of essentially the same material. OAS is a popular alternative
to acrylic because it costs less and therefore helps to reduce the overall cost
of the spa. Many people also prefer the simpler, plain appearance of OAS to the
more lustrous look of acrylic.
For those of you who enjoy a really complicated scientific name, the specific
nomenclature for OAS is ASA/AES terpolymer. It is an acrylic-styrene-acrylonitrile
blend with olefin modified acrylonitrile-styrene co-extruded over acrylonitrile-butadiene-styrene
(ABS) backing. No wonder most people would rather call it OAS.
• Acrylic. Acrylic is a smooth, high gloss material that most spa
manufacturers have chosen for their spa shells. Its benefits include a wide
array of colors and styles (including two and three color marble patterns and
simulated granite) plus a smooth, high-gloss finish. This finish gives the spa
shell a luxurious sheen that’s easy to clean, and its non-porous surface helps
prevent dirt from accumulating. It’s very stain resistant, making shell
maintenance simple and easy.
Acrylic comes in several different types that can be used in the formation of a
spa shell. Check with the spa manufacturer for specific details about the type
of acrylic they use and the benefits it provides.
