Materials for Waterpark Ride Seats
- Category: Case Histories
- Published on Monday, 03 August 2009 21:07
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Alberts Company Process Produces Polyurethane Seating to Reduce Ride Maintenance Costs
Long time manufacturer of custom-molded parts using advanced processes and techniques, The Alberts Company, Inc., Montoursville, Penn., is now rotocasting polyurethane seats for waterpark rides to reduce maintenance time and costs for amusement and theme-park operators.
The new seats feature a streamlined design that replaces traditional foam-andmetal composition with a strong, seamless polyurethane shell into which a low-cost foam pad is inserted. The next-generation seats, molded from an advanced polyurethane supplied by Innovative Polymers, Inc., Saint Johns, Mich., are waterproof and 40% lighter than old-style seats to reduce wear-and-tear on ride support structures.
Brian Mitchell, Production Manager, says, “Our rotocast polyurethane seats have a service life three to four times longer than traditional seats because the shell does not rust and the pads are easily replaced on-site without necessitating a costly and timeconsuming reclamation process.”
The Alberts Company has designed and molded theme park ride restraints for amusement parks for many years. Among its customers are Busch Entertainment, Cedar Point and ride manufacturer Zamperla.
Originally, water-ride seats were built with a steel frame covered by flexible opencell foam. In service, the foam absorbed water causing it to degrade and the underlying metal to rust. For repair, seats were removed from the ride and returned to the manufacturer where foam padding was removed, the frame refurbished and new foam padding installed. The overall process was expensive, requiring a significant amount of labor plus the cost of shipping heavy seats to and from the factory.
Several years ago, The Alberts Company began investigating the use of rotocasting for molding of lightweight, plastic seats. The new ride parts were designed with a shallow depression that allowed for fast installation of a ¾-inch foam pad on which passengers sit. Seat backs were engineered to withstand use as a “hand hold” for passengers boarding and exiting a ride. The new seating proved to be a durable alternative to metal seats.
Most recently, The Alberts Company began building seats from an Innovative Polymers high-performance polyurethane to realize improved processing and endproperties.
The IE-3050 polyurethane now in use is formulated specifically for rotational molding. It has a very low viscosity and a 5 to 7 minute gel time that provides for even, complete coating of mold surfaces. The mercury-free polyurethane cures in quickly, permitting part demolding in as little as 30 minutes. Completed seats combine rigidity with good tensile strength.
To mold each seat, equal parts of IE-3050 resin and hardener are mixed and injected into a fully released epoxy/fiberglass mold. The mold is then rotated along both X and Y axes at varied speeds to produce a polyurethane coating of consistent thickness on the mold surfaces. After curing, the shell is backfilled with rigid foam for added strength.
Mitchell explains, “Initial set-up for a seat is a combination of expertise and trialand-error. We make a part, cure it and then cut it up to examine wall thickness and consistency. If too much polyurethane is used, the walls may incorporate lumps of plastic while too little material may result in unacceptably thin or uneven walls. By varying processing speeds and material amounts, a formula is ultimately finalized that yields consistent, high-quality parts.”
In service, the seats molded from Innovative Polymers IE-3050 polyurethane stand up to the rigors of use, providing ride operators with the required durability and low maintenance.