Residential Glass Bending Guidelines

Transcription

1 Glass Section 1 GENERAL BENDING OVERVIEW 1.1 In addition to being used in flat heat-treated applications, Guardian s Low-E coated glass products have been successfully bent. To maintain aesthetics and ensure superior performance, special care must be taken during the fabrication of these products. This Product Application Note offers requirements that when followed, will reduce the chances of damage to the coating during the bending process. Failure to adhere to these guidelines may void the warranty. Section 2 PREREQUISITES FOR BENDING 2.1 Prior to initial fabrication, Guardian Field Customer Engineering must conduct a certification visit at the customer s fabrication facility. 2.2 Identification of the coated surface must be done with a low-e coating detector or an ohmmeter. Figure 1. Coating Detector 1

2 2.3 Coating detection, handling, cutting and washing must be done in accordance with requirements set-forth in the Guardian s Low-E Fabricator User s Guide. 2.4 In preparing the glass for entry into a bending furnace, the coated substrate must be machine washed with the coating facing up and away from conveyor rolls. Washer drum brushes (low-e brushes mandatory) may have to be raised prior to bending. A hot [55 66 C ( F)] detergent wash, followed by a warm [18 32 C (65 90 F)] distilled; de-ionized or reverse-osmosis treated water rinse is required. 2.5 Washed glass must be totally dry and free of fingerprints and other contaminants. Note: Close inspection of the coated glass following the washing process is required. Fine scratches produced by washing will be further enhanced during the bending process. 2

3 Section 3 GENERAL INFORMATION FOR BENT ANNEALING 3.1 Interleaving release agents such as talc and isopropyl alcohol may be used during the bending process. However, post-bend residual release agents must be removed using a clean, soft cloth saturated with water. 3.2 During the bending process, glass temperature must not exceed 605 C (1120 F) and the ambient temperature must be at or below 630 C (1166 F). If this temperature is exceeded, coating degradation may occur. Note: The thermal reflective properties of Guardian s Low-E coated glass products will render top-mounted measuring devices inaccurate. 3.3 As soon as the bending process is complete, the glass must be immediately brought down to a temperature of 515 C (970 F), from which the slow annealing cycle may begin. 3.4 Radical bends may cause coating stretch or crazing. 3.5 Full-scale mock-ups must be produced prior to accepting live orders to ensure the suitability of the coating for the intended use. 3

4 Section 4 BENDING GUARDIAN S RESIDENTIAL LOW-E COATED GLASS PRODUCTS 4.1 Guardian s Low-E coated glass products will generally require edge deletion prior to bending. For more information on edge deletion, review the Guardian s Low-E Edge Deletion and Sealant Product Application Note, Edge Deletion Requirements. Products within this category include ClimaGuard HT, 63 HT, 55HT, ClimaGuard DT, and Performance Plus II HT. 4.2 During the bending process, optimal results will be obtained by placing the coated lite on top of a dual-lite stack, with the coating facing upward away from the mold. 4.3 A coated lite must be bent singularly or over its uncoated mate. Do not stack glass on top of the coated surface. 4.4 Due to the reflective properties of Guardian s Low-E coated glass products, extended soak times are necessary. 4.5 Applications involving coating on the #2 surface (convex or concave) must not exceed a bend radius of 2032 mm (80 in.). 4.6 All Guardian coated glass products must be insulated or laminated after bending. Guardian s coated glass products must not be used for monolithic applications. 4.9 Inspection of bent parts must be done in accordance with requirements set forth in the Guardian s Coated Glass Fabricator User s Guide. 4

5 Section 5 CONVEX AND CONCAVE BENDING 5.1 Convex or concave applications will be determined by both the orientation of the coated surface and the mold shape. Figure 2. Convex Bend. Coating facing upward away from mold. Final application places the coating on the #2 surface. Figure 3. Concave Bend. Coating facing upward away from the mold. Final application places the coating on the #2 surface. 5

6 Section 6 BENDING TERMINOLOGY CONVEX CONCAVE SERPENTINE CURVE COMPOUND CURVE When viewed from the exterior, the curve bends toward the observer. CIRCUMFERENCE When viewed from the exterior, the curve bends away from the observer. POINT OF TANGENCY A condition of having concave [R1] and convex [R2] curves in the same plane. TANGENT A condition having curves in horizontal and vertical planes. RADIUS The length of a curve or arc of a circle. It must be specified whether the measurement is along the exterior or interior face of the glass. CHORD The point at which a straight line meets a curve or arc. Determination of this point is crucial for the interfacing of curved glass and metal. A straight line exiting an arc or curve. Sometimes referred to as a straight leg. The dimension or measurement of an imaginary line taken from the center point of a circle to the arc or circumference of the circle. GIRTH DEGREE OF ARC HEIGHT The dimension of an imaginary straight line connecting the end points of a curve or arc. Sometimes referred to as the point to point dimension or measurement. RISE The length of a curve or arc required. The dimension or measurement of the material required if viewed in a stretchedout or flattened state. The longer girth must be specified. Every circle, regardless of radius, contains 360 degrees of curvature. The girth or arc length of curved glass can be determined when the degree of arc is given. The straight edge of a lite of glass as opposed to the girth dimension. Could also be referred to as the width dimension if the lite is installed in an overhead application. In geometric terms, the rise is known as the height of the arc. While not critical when adequate information is submitted, the rise can be used in conjunction with the chord dimension to calculate an unknown radius or girth. COMPRESSION Pressed together, made more compact by pressure. TENSION Stress on a material produced by the pull of forces tending to cause extension. Sources: GANA Glazing Manual 2004 and Webster s New World College Dictionary [4 th edition]. 6

7 Section 7 ADDITIONAL INFORMATION 7.1 Every effort has been made to ensure the accuracy of the information in this document. This information is intended to assist in the proper application and use of Guardian coated glass products and does not constitute a warranty for any particular purpose. The only warranties offered by Guardian on coated glass products are Guardian s published Coated Glass Limited Warranties. 4.2 For additional information or technical support with any coated glass products, please contact Guardian s Customer Engineering Group at