GMNA-GM1131M-2004.pdf

ENGINEERING STANDARDS Material Specification Adhesives GM1131M Sealing Compounds for Use With Fasteners and Attaching Clips 1 Scope This specification covers the more common types of sealing materials used in conjunction with fasteners (screws, nuts, and attaching clips), which are assembled into attachment holes in sheet metal. Holes intended to receive fasteners are generally designed with considerable clearance necessitating the use of a sealing material to fill the balance of the hole remaining after insertion of the fastener. Sealing materials for this service are required to prevent the penetration through the hole cavity of road splash, dust, etc.; also, to afford protection from corrosion where paint may have been chipped fro the edges of the hole during assembly. Dependant on the end use, composition, and application, the seals may be cut, molded, cast, or extruded. Normally these seals are specified as a preshaped, ready for use part and often assembled to the part for which they are designed. This specification is intended to cover only basic requirements. More detailed requirements for individual applications shall be specified in engineering drawings, purchase order and/or in other agreements between supplier and purchaser. 1.1 Material Description. 1.1.1 Material Identification. Materials fall into several composition categories as follows: Type A. Compounded rubber base which may be vulcanizing or non-vulcanizing type and must be of a uniform composition. Type A-1. Heat Resistant Composition similar to Type A. Sealer is to withstand reflow lacquer oven temperature schedule in addition to meeting all other requirements of this specification. Type A-2. Heat Resistant Composition similar to Type A. Sealer is to withstand sustained temperatures of 205 C without losing its sealing qualities in addition to meeting all other requirements of this specification. Type B. Plasticized reclaim rubber with cellulosic fiber filler that may be either extruded or die cut. Type C and C-1. Synthetic rubber and wax composition. Type D, E, F, G, and H. Closed cell sponge or foam types, usually made from vinyl plastisols, although other compositions are possible. Type J. Closed cell neoprene sponge. Type K. Composition, usually vinyl plastisol, is cast in place and subsequently cured. The finished seal is substantially solid as distinct from foam types. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ASTM A925 2.2 GM Standards/Specifications. GMW3001 GMW3059 3 Requirements 3.1 General. Seals shall have good aging properties and shelf life storage. They shall not show visible signs of deterioration under any of the test conditions of this specification. Tests shall be conducted with the compound fully exposed unless assembly is specified. 3.1.1 The sealing function must be maintained throughout the life of the product into which it is assembled. 3.1.2 The cohesion of the seal and its adhesion to the associated part must be such that the assemblies can be handled and shipped without objectionable sealer deformation or separation of the seal from the assembly. 3.2 Odor. The odor of the seal shall not be objectionable and must not be more perceptible with age. Weight. The weight or density should not vary ± 5% from that of the originally approved materials. © Copyright 2004 General Motors Corporation All Rights Reserved October 2004 Originating Department: North American Engineering Standards Page1 of 4 Copyright General Motors North America Provided by IHS under license with GM Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 06/23/2008 23:36:47 MDTNo reproduction or networking permitted without license from IHS -,-,- GM1131M GM ENGINEERING STANDARDS © Copyright 2004 General Motors Corporation All Rights Reserved Page 2 of 4 October 2004 3.3 Shelf Life. The assembly shall not deteriorate beyond usability after 12 months of plant storage in shipping containers. 3.4 Compatibility. Seal compositions must be compatible with other body sealing materials. Clip sealer and primer compositions must be selected to avoid cross-plasticizing effects. 3.5 Hardness (As Received). On Types A, B, and C the hardness is controlled by penetrometer. Using the ASTM Needle Penetrometer 1.00 N (100 gm) total load at 25°C, 5 second reading, the penetration must be not less than 3.5 mm nor more than 5.5 mm. 3.6 Aging Characteristics. The seal must not harden appreciably (beyond specified torque limits or more than 20 % of the original penetration value) after 14 days aging at 70°C nor shall the seal show shrinkage that would effect service of the part. 3.7 Staining. The material used in the seal shall not cause any migration staining against acrylic lacquer or glyptal enamel, when exposed for 24 hours to the sunlamp apparatus described in ASTM A925, Method B, migration stain. Contact stain, where checked as above, is permissible. Moderate plasticizing of the color finish at the contact area only is permissible. 3.8 Paint Touch-Up Flow Temperature (Acrylic or Alkyd Base Paints). None of these compositions must flow or bleed beyond the contact area, become hard or brittle, or shrink sufficiently to cause leakage after exposure for 30 min at 93°C. 3.9 Corrosion. When prepunched painted test panels are exposed to corrosion conditions, salt spray, humidity, etc., the condition of the corrosion developed underneath and surrounding the seal must not be inferior to that present on an adjacent hole without the seal. 3.10 Cold Temperature Flexibility. The sealing compound shall not crack when uniformly folded 180° over a mandrel 4 times the thickness of the material that has been conditioned at 29°C for 24 hours. The seal shall not harden or shrink sufficiently to cause cracking and subsequent leakage at the assembly. 3.11 Sealing Properties. Where a specific test method applies, as in Type K, that test method takes precedence, otherwise the following generalized test method applies. 3.11.1 Several samples of the seal and its associated parts, as received, are assembled to simulate actual use and test. Use conditions include moldings, metal gauges and contours, hole sizes and shapes, screw torques, paint, or any other conditions normally present. Screw torques will be the upper limit called for by fastener torque specifications for the part involved. Holes are to be punched or drilled with the burr on the same side as the production usage. Painted panels must be according to standard painting procedure. 3.11.2 The assemblies, made as above, are tested in a simulated production water test. By this test, the seal assembly is considered acceptable if no leaks appear, or if an initial water spot is not continuing. Several assemblies, after passing this preliminary test, are subjected to an aging condition as follows: a. 24 h at 100% R.H. and 38 C, followed by b. 24 h at 70 C in circulating air, followed by c. 24 h at 29 C d. repeat a, b, and c three times 3.11.3 After recovering at room temperature overnight the assemblies are subjected to and must pass the seal test before aging. 3.12 Torque Retention Test on Assemblies (For Sealing Hex Nuts). The assemblies for test shall be made up by taking stainless steel automobile body moldings and attaching them to primed (one side) and lacquered (other side) 0.90 mm metal panels using typical molding spring clips and bolt assemblies along with the proposed sealing hex nut. The hole size in the panels shall be such that when the nut is assembled on the bolt, and the periphery of the bolt is touching one side of the hole, the washer shall overlap the opposite side of the hole by 1.50 mm. Half of the completed assemblies are then torqued to 1.1 Nm, and the remainder to 2.3 Nm with a calibrated wrench. 3.12.1 Individual assemblies shall be subjected to each of the following test conditions: Room temperature 72 hours. a. Temperature of 93°C for 3 hours. b. Accelerated Aging for 14 days at 70°C. c. Cycle test consisting of 3 complete cycles as follows: 1. 24 h at 38°C and 100% R.H. 2. 24 h at 70°C Copyright General Motors North America Provided by IHS under license with GM Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 06/23/2008 23:36:47 MDTNo reproduction or networking permitted without license from IHS -,-,- GM ENGINEERING STANDARDS GM1131M © Copyright 2004 General Motors Corporation All Rights Reserved Page 3 of 4 October 2004 3. 24 h at 29°C 3.12.2 The sealer must not, after exposure to any of the above treatments, produce any appreciable exudation of compounding oils, stabilizers, plasticizers, etc. These oils, when present in limited quantities, must not plasticize either production primers or production acrylic lacquers more than a moderate amount at the contact areas only. Under all conditions of test listed above, the minimum torque after test and normalizing assemblies to room temperature shall be 0.8 and 1.7 Nm from an initial torque of 1.1 to 2.3 Nm respectively. The maximum torque loss permitted for other mall size fasteners is 30%. All torque rechecks must be in clockwise rotation. 3.12.3 Sealing Ability of Above Assemblies (for sealing hex nuts). The sealing nut assembly, upon completion of the “torque retention” test, shall withstand a 20 kPa of water for a period of 100 h without showing any sign of leakage. 3.13 Heat Resistance (To Reflow Lacquer Over Temperature Schedule Type A-1 Only). This sealer must not age harden more than 20% of the original penetration value after having been exposed to lacquer reflow oven temperature schedule of 25 minutes at 177°C. After this temperature exposure, the sealer must meet the requirements of the balance of this specification. 3.14 Load Deflection (Type K Vinyl Plastisol). This material must conform with the following load deflection limits when tested with a link spring tester or equivalent. Readings are taken after 15 s at the specified load to allow for creep characteristics. 3.14.1 As Received: 45 NDeflection 0.50 0.90 mm 220 N. Deflection 0.90 1.25 mm 3.14.2 Aged 14 Days at 70° °C 45 NDeflection 0.060 1.0 mm 220 N. Deflection 1.15 1.50 mm 3.15 Torque-Tension (For Stamped Metal Self- Threading Nuts). 3.15.1 Make typical joint assemblies in dynamic torque-tension recording equipment. Preset a Rockwell 31F-476A pneumatic power wrench or equivalent according to Table 1 using a Chicago Pneumatic CP-200 torque analyzer or equivalent. The typical assemblies shall be made in tension recording equipment. The nut is to be driven against plain steel panel surface with suitable clearance holes for respective zinc die cast stud diameter. Parts must be shimmed when necessary to engage nut helix (thread) at critical diameter of stud as shown on respective part drawing. Note: The developed dynamic tension must meet the requirements for Table 1 for: a. Nut with as-received sealer b. Nut with sealer aged 14 days at 70°C prior to testing. 3.15.2 Conduct a torque-to-failure assembly test using manual torque on zinc or steel as required and allow by design a 25% safety factor in excess of established maximum assembly torque. 3.15.3 Determine ratio of assembly torque to residual (hand) torque at initial and 24 h period when assembled with specified pneumatic wench preset to specified inch-pounds (See Table 1) on CP-200 Torque Analyzer or equivalent. Note: Parts must conform to minimum initial and residual (24 h) values shown on respective part drawing. 3.15.4 Remove nut and mastic sealer assembly after power tool torque down and observe for visual evidence of contact (scoring) of washer to panel. Note: The assemblies must exhibit good (80% nominal) fastener metal-to-panel metal contact at above specified power tool torque setting. 3.16 Heat Permeability. Type A-2, after exposure to 205°C for 1 h, the material must provide an airtight seal at 7.0 kPa min pressure. Copyright General Motors North America Provided by IHS under license with GM Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 06/23/2008 23:36:47 MDTNo reproduction or networking permitted without license from IHS -,-,- GM1131M GM ENGINEERING STANDARDS © Copyright 2004 General Motors Corporation All Rights Reserved Page 4 of 4 October 2004 Table 1: Minimum Recommended Values for Developed Residual Tension Typical Part Finish Finish Nominal Size mm (in.) Power Tool Analyzer Torque Setting a. Sealer As Received b. Sealer Aged 9420262 Zinc 6.3 x 11.0 x 17.5 (1/4 x 7/16 x 11/16) 7.9 Nm (10 in-lb) 1335 N (300 lb) 890 N (200 lb) 9432461 Zinc 6.3 x 11.0 x 22.0 (1/4 x 7/16 x 7/8) 7.9 Nm (10 in-lb) 665 N (150 lb) 665 N (150 lb) 4 Manufacturing Process Not applicable 5 Rules and Regulations 5.1 All materials supplied to this specification must comply with the requirements of GMW3001, Rules and Regulations for Material Specifications. 5.2 All materials supplied to this specification must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 6 Approved Sources Not Applicable 7 Coding System This material specification shall be referenced in other documents, drawings, VTS, CTS, etc. as follows: Material per GM1131M Type A 8 Release and Revisions 8.1 Release. This standard was originated by Fastener Specialist Team in February 1991 and approved in February 1996 8.2 Revisions. Rev Approval Date Description (Organization) C SEP 1998 Editorial Revisions (Fastener Specialist Team) D MAR 2004 Editorial Revisions (Fastener Specialist Team) Copyright General Motors North America Provided by IHS under license with GM Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 06/23/2008 23:36:47 MDTNo reproduction or networking permitted without license from IHS -,-,-