US Spa uses the Aristech Quarite Plus acrylic plastic for all of our spa shells.This a two ply, 325 mil laminated material. Most other shell manufacturers heat and vacuum form a 125 mil sheet of Acrylic into the spa shell form. Since this thin shell has very little strength, the shell requires several layers of fiberglass to be applied.  The Quarite Plus acrylic material that US Spa purchases from Aristech has already been laminated with a 275 mil ABS plastic backing. Thus, we start the vacuum molding process with material that is more than twice the thickness of used by most other manufacturers. Sporting a granite look, its patented pebble-like texture minimizes water spots, and surface damage from sunlight and chemical sanitizers.

The vacuum molding is done in a unique updraft fashion called “Invert-Forming”.  This process prevents the heated material from prematurely coming in contact with the cooler mold and cooling the material non-uniformly. “Invert-Forming” insures uniform thickness of the spa shell.

US Spa is one of only a handful of spa manufacturers worldwide to use Aristech’s state-of-the-art Hyrizon Hybrid Foam Resin for reinforcement and insulation. The shell is sprayed with the foam, which hardens and provides the rigidity needed.  The foam rises as it hardens to a density of approximately 30 pounds per square foot and has similar stiffness properties to an acrylic surface that has been reinforced with three layers of Fiberglass Reinforced Polyester (FRP).  Most spa manufacturers still use the time consuming, labor intensive FRP rollout method to reinforce the Acrylic. Since fiberglass lamination is such a lengthy (6-8 hour) manual process there are many opportunities for human error and contamination of the laminate material as it cures. Over time, these manufacturing defects can result in blistering, peeling and de-lamination. The Hyrizon foam cures in approximately ten minutes.  If there are any defects or bubbles, they will be seen and corrected at the factory.