CompositesWorld
Issue link: https://cw.epubxp.com/i/517026
JUNE 2015 48 CompositesWorld INSIDE MANUFACTURING this is a rare step for polyester compos- ites fabrication, Kreysler points out that in exterior applications, laminates will, indeed, postcure with sufcient time and/or exposure to temperature. "We did not want to risk that a panel not cure completely for some reason, get installed and then postcure on the building and warp," he explains. Pre-installation framing Because the uncored FRP panels were only 4.8 mm thick but 1.7m wide, aluminum framing was installed on all four edges with intermediate crossmem- bers to stifen the panels and serve to connect each FRP panel to its Enclos-built unitized wall-panel backing structure. Steel rods were inserted into holes drilled along the lengths of the intermediate stifeners. A 90° elbow at the end of each rod ft into a groove in a composite attach- ment plate, which was then bonded to the FRP laminate using Plexus methyl meth- acrylate adhesive from ITW Polymers Adhesives (Danvers, MA, US, see Step 5). Te fnal step performed at Kreysler's factory was sandblasting to produce a sandstone-like matte fnish (Step 6). "We have used this fnish on buildings for 20 years, and they still look great," touts Kreysler. "It is easy to repair, does not oxidize easily and does not stain like concrete because it does not absorb moisture." After fnal quality assurance checks and documentation, the panels were ready to ship. Enclos leased a building in nearby Vallejo, CA — standard procedure for the company, which establishes an "assembly site" near each job site, where it receives aluminum extrusions, glass or metal panes, gaskets and attachment hardware from suppliers. Everything is computer- designed, pre-ordered to custom sizes and assembled into ready-to-install wall panels away from the job site, where quality control can be better maintained. Tis also reduces complexity and risk at the building site. Tus, as Enclos assem- bled each unitized wall system panel for the SFMOMA expansion, it received and attached the matching FRP rain screen panel from Kreysler & Associates (Step Notably, a sand component is added to create a matte fnish that resembles sandstone, yet also shimmers when directly lighted. Behind the cured gel coat, three layers of woven glass fber roving wet out with a resin impregnator were applied (see Step 4, p. 46). Kreysler used a polyester resin supplied by Ashland Performance Materials (Dublin, OH, US) and a special-order fabric sourced through distributor Core Composites (Bristol, RI, US). "We wanted an equal number of strands in both warp and weft directions, and also a custom width that matched our average panel width [1.7m]," Kreysler reveals. Panels were allowed to cure at room temperature for several hours. But after demolding, they were postcured at 65°C for three hours in a custom-built oven. Although TECHNICAL FIBRE PRODUCTS INC. E: inquiries@tfpglobal.com • T: 1 518 280 8500 Advanced nonwovens provide lightweight solutions for: High Quality Surface Finish EMI Shielding Electrical Conductivity Enhanced Corrosion Resistance Abrasion Resistance Fire Protection Fracture Toughness Improvement Find out more about our diverse range of high quality OPTIVEIL®, OPTIMAT® and TECNOFIRE® nonwovens and our capability to develop custom nonwovens to meet specifc performance, aesthetic or processing requirements at www.tfpglobal.com. SURFACE ENGINEERING FOR COMPOSITES FROM TECHNICAL FIBRE PRODUCTS Visit BOOTH 1726 at JEC Americas • Houston • 2-4 June