Spa producer Hawkeye Manufacturing and resin supplier AOC have collaborated to produce one of the largest, most complex single-piece spa liners on the market.
The Bossetti combination spa and hot tub from Barefoot Fitness Spas is a 2000-gallon tub with seating for five adults, 37 stainless-steel spa jets, 6 adjustable-flow swim jets, flow fountains and a waterfall.
Hawkeye Manufacturing, Richmond, Virginia, USA, uses AOC materials and technical support to ensure the quality and durability of this product. “With a unit this large, we had to be right the first time,” declares Casey Murray, Vice President for Hawkeye Manufacturing. “The unit’s size makes it difficult – and more expensive – to transport and install. Any issues in the field would create an enormous cost.”
Hawkeye starts with a sheet of acrylic that is heated and vacuum-formed into the shape of the spa’s smooth, seamless uni-liner. After mastering the technique for forming the large, complex Bossetti liner, the next challenge was developing a protocol for the fibre reinforced polymer (FRP) structural composite back-up.
According to Murray, the major concerns for the composite manufacturing step were:
- precisely controlling composite thickness variations that are needed for the complex liner;
- controlling the exothermic heat generated during composite cure to prevent spikes that could distort the liner shape; and
- ensuring an extremely strong adhesion between the composite and liner.
The first step for the composite is the application of a skin coat consisting of chopped glass fibres and high performance AOC Altek® H100 vinyl ester resin. This technique is similar to that used in boat building and serves the same purpose, to prevent moisture from reaching and affecting the integrity of the thicker composite structure. The vinyl ester also provides excellent adhesion between the composite and acrylic. To finish the back-up laminate, Hawkeye applies chopped fibre in Altek C949 polyester resin.
“This spa is larger than anything we have ever produced before,” Murray states. “The consistency of AOC resins and outstanding AOC technical support were essential to helping us reach this milestone.”