technical data DeSoto conductive coatings DeSoto Click here to view Application Guide

Transcription

1 Click here to view Application Guide technical data DeSoto conductive coatings DeSoto conductive coatings Description DeSoto conductive coatings are conventional solids, carbon filled, epoxy-amine coatings with controlled conductive properties. These high performance coatings are designed to obtain surface conductivity on non-conductive (composite and other plastics) substrates. Additionally, DeSoto conductive coatings control static charge bleed-off on radomes, antennas, and other insulative parts. DeSoto anti-static coating (528X306) is used to bleed-off the static charge from the aircraft s radome and antennas. This coating has a resistivity requirement between 1.0 to 100 megohms per square inch, and requires a BMS or BMS primer before topcoating. DeSoto conductive coating (528X310) is used on non-conductive substrates to facilitate the discharging and positive grounding of static electrical charges to the primary structure. This coating has a much higher surface conductivity, with the resistivity requirement between 0.1 to 100,000 ohms per square inch. The application of a BMS or BMS primer prior to topcoating is highly recommended. DeSoto conductive coatings are compatible with all conventional, airless, and HVLP spray equipment. For important details on the application parameters for these primers, consult the application guide for DeSoto conductive coatings or contact your local PRC-DeSoto International Application Support Center. DeSoto conductive coatings are qualified to the following specifications: 528X306 BMS Type II CMS Type II GMS 5003 LES X310 BMS Type III CMS Type III BPS DeSoto conductive coatings are compatible with the following primer and topcoat specifications: Primers BMS Type II & III BMS CMS Topcoats BMS Type I & II BMS Type VIII CMS Type II Application temperature 65 F - 95 F (18.3 C to 35 C) Application humidity 40% - 75% Mix ratio (by volume) 1 part base 528X306/528X310 1 part curing solution 910X464 Viscosity Initial mix, #1 Zahn cup sec. Pot life (4 hours) 40 sec. max. VOC, EPA method grams/l Dry film density 528X lbs/ft 2 at 1.0 mil dry film 528X lbs/ft 2 at 1.0 mil dry film Theoretical coverage 528X ft 2 /gal at 1.0 mil dry film 528X ft 2 /gal at 1.0 mil dry film Recommended dry film thickness 0.6 to 1.0 mils (15-25 microns) DeSoto Aerospace Coatings PRC-DeSoto International, Inc San Fernando Road, PO Box 1800 Glendale, California (818) Fax (818) Date issued: 8/01 Supersedes: 2/99

2 DeSoto conductive coatings Drying 75 F (23.9 C) and 50% R.H. Duct free 15 min. max. Tack free less than 2 hrs Dry through 4 hrs Dry to overcoat 4 to 24 hrs Full cure 7 days Accelerated cure 15 minutes flash 75 F (23.9 C), then minutes at 140 F (60 C) & 5% R.H. min. Color Jet black 60 degrees 30 units max. Spray equipment Compatible with conventional, airless and HVLP spray equipment Shelf life 12 months from date of manufacture Performance properties Service temperature -65 F to 350 F (-54 C to C) Conforms Film hardness F pencil minimum Conforms Surface resistivity 528X to 100 mega ohms/square inch 528X310.1 to 100,000 ohms/square inch Fluid resistance BMS 3-11, 30 days 75 F (23.9 C) Conforms Distilled H 2 0, 7 75 F (23.9 C) Conforms Fastener corrosion Salt spray for 250 hours Conforms Rain erosion (528X310 only) 385 miles per hour exposure with a 3 to 4 inch per hour water spray for 30 minutes Conforms Adhesion Cross-hatch adhesion Conforms Note: The application and performance property values above are typical for the material, but not intended for use in specification or acceptance inspection criteria because of variations in testing methods, conditions, and configurations. Storage life Inspect the condition of the container to ensure compliance to FED-STD-141, Method The material should be stored at temperatures between 40 F to 115 F (4.4 C to 46.1 C) to ensure shelf life. Health precautions This product is safe to use and apply when recommended precautions are followed. Before using this product, read and understand the PRC-DeSoto International Safe Handling Guide for aerospace coatings and the Material Safety Data Sheet (MSDS), which provide information on health, physical and environmental hazards, handling precautions, and first aid recommendations. An MSDS and the Safe Handling Guide are available on request. Avoid overexposure. All mixing and spraying must be conducted with adequate ventilation and proper personal protective equipment as recommended. Obtain medical care in case of extreme overexposure. For industrial use only. Keep away from children. For emergency medical information call For sales and ordering information call AEROMIX ( ). DeSoto is a trademark of PRC-DeSoto International, Inc., registered with the U.S. Patent Office. All recommendations, statements, and technical data contained herein are based on tests we believe to be reliable and correct, but accuracy and completeness of said tests are not guaranteed and are not to be construed as a warranty, either expressed or implied. User shall rely on his own information and tests to determine suitability of the product for the intended use and assumes all risks and liability resulting from his use of the product. Seller s and manufacturer s sole responsibility shall be to replace that portion of the product of this manufacturer which proves to be defective. Neither seller nor manufacturer shall be liable to the buyer or any third person for any injury, loss, or damage directly or indirectly resulting from use of, or inability to use, the product. Recommendations or statements other than those contained in a written agreement signed by an officer of the manufacturer shall not be binding upon the manufacturer or seller. Printed in U.S.A.

3 DeSoto conductive coatings application guide

4 PRC-DeSoto International Specifications BMS Type II and Type III Product codes 528X306/910X464 (Type II) 528X310/910X464 (Type III) Replacement for Type I Material inspection prior to use Prior to using, inspect the containers for damage or leaks that may have occurred during shipping. The condition of the curing solution is an important factor in obtaining the optimum properties from the coatings. Appearance of a white haze indicates moisture contamination. Use DeSoto conductive coatings are carbon filled, epoxyamine coatings with controlled conductive properties used to obtain surface conductivity on non-conductive substrates (fiberglass and other plastics). The coatings control static charge bleed-off on radomes, antennas, composites and other insulative parts. BMS Type II is used on radomes and antennas and has a resistivity requirement of between 1.0 to 100 megohms per square. BMS Type III is used on non-conductive substrates to facilitate the discharging and positive grounding of static electrical charges to the primary structure. It has much higher conductivity (lower resistivity) than Type II. The resistivity requirement is between 0.1 to 100,000 ohms per square. Surface preparation Thorough surface preparation and cleaning prior to applying the conductive coatings is extremely important to obtain the desired resistivity. Follow the surface preparation instructions below before applying the conductive coatings: 1. The surface of the non-conductive laminate should be lightly sanded with a 180 grit or finer sandpaper to remove the glossy finish. Note: The resistivity of conductive coatings is directly related to the condition of the substrate surface. Sanded and rough substrate surfaces on which the coating is applied will lower the resistivity. Smooth and glossy substrate surfaces will increase the resistivity. 2. The sanding dust should be removed by wiping with a clean rag. Mixing Before mixing any paint, the material should be allowed to reach room temperature. This can be achieved by leaving the material in the shop for approximately 24 hours before mixing. Be sure all mixing and measuring containers are clean and free from contamination. Shake the base or stir it thoroughly until there is no solid material left on the bottom of the can. The mix ratios of Type II and Type III products are one to one by volume. Mix one part by volume of base with one part by volume of curing solution. Always add the curing solution slowly while stirring the base. If the material is added in the wrong order or all at once, local areas of incompatibility can occur. This will cause the resin or vehicles to kick out into small solid particles. These particles are difficult to redisperse and can create a rough surface or cratering. Pot life Type II and Type III products require 30 minutes of induction time. Strain the mixed coating through a fine mesh nylon cloth to remove any particles that may have been introduced into the coating during mixing and measuring. Stir the mixed material before and during use. The typical pot life of these coatings at 77 F (25 C) is four hours. Note: The resistivity of these coatings slightly increases during its pot life. The resistivity of a coating sprayed during the first hour of pot life can be lower than the resistivity of a coating sprayed during the third hour of pot life. Note: Discard any unused material that has exceeded its usable pot life. 3. Immediately before applying the conductive coating, wipe the surface with a clean rag and a suitable solvent such as Desoclean 110 cleaner. 2

5 Spray equipment These conductive coatings have been developed for use with conventional or HVLP spray equipment. HVLP BINKS Mach I Tip size #91-#94 Pot pressure psi Atomization pressure at gun 10 psi maximum GRACO 1265 Tip size to Pot pressure psi Atomization pressure at gun 10 psi maximum Coating application Spray apply these coatings to a dry film thickness of 0.6 to 1.0 mil (15 to 25 microns). Note: Spray technique is extremely important in controlling coating resistivity. Dry spraying will reduce resistivity and wet spraying will increase resistivity of the coating. Note: Dry film thickness is another important variable in controlling coating resistivity. In Type II applications, increasing the film thickness will increase resistivity. Application conditions Optimum conditions for application of these topcoats are 68 F to 86 F (20 C to 30 C) and 20% to 60% relative humidity. Cure conditions Before measuring the resistivity, the coating must be allowed to cure for seven days at 75 F (24 C). To accelerate this process, the coating can also be cured at 135 F to 145 F (57 C to 63 C) for 30 minutes after a 15 minute flash off period at 75 F. Note: Resistivity of the coating is directly related to its cure. A partially cured coating will have high resistivity. Electrical resistance test The following procedure is used to determine the resistivity of conductive coatings: 1. Prepare three panels for each test. The panels should be epoxy fiberglass laminates with approximate dimensions of 0.03 X 4 X 6 inches (.08 X X cm). 2. Lightly sand and clean the surfaces of the test panels according to the surface preparation procedure outlined above. 3. Spray apply the coating to a dry film thickness of 0.6 to 1.0 mil. 4. Cure the coating either for seven days at 75 F or flash off for 15 minutes to allow the solvent to evaporate and then cure for 30 minutes at 140 F+5 F. 5. Determine the resistance per square of the coating using an ohmmeter and 3M conductive electrical tape (Copper X-1181 or Aluminum X-1170). If the resistance of the coating is too high, the following procedure is recommended: a) Thoroughly abrade the fiberglass surface. b) Apply the coating at the beginning of its potlife. c) Dry spray the coating. d) For a Type II coating, maintain the dry film thickness near the minimum specification requirement (0.6 mil). For a Type III coating, maintain the dry film thickness near the maximum specification requirement (1.0 mil). If the resistivity of the coating is too low, the following procedure is recommended for a Type II coating: a) Do not abrade the surface before applying the conductive coating. b) Apply the coating near the end of its pot life. c) Wet spray the coating. d) Maintain the dry film thickness near the maximum specification requirement.

6 Clean up Flush equipment with Desoclean 45 cleaner or Desoclean 110 cleaner. The coating is a chemically reacting system. It is no longer soluble in solvents after it has cured. For this reason, clean equipment as soon as possible after the coating has been applied and always before the material has cured. Note that even a fresh coating deposits a film on the equipment that does not dissolve easily. Agitation with a brush or cloth will help to remove these deposits. Health and safety This product is safe to use and apply when recommended precautions are followed. Before using this product, read and understand the PRC-DeSoto International Safe Handling Guide for aerospace coatings and the Material Safety Data Sheet (MSDS) which provide information on health, physical and environmental hazards, handling precautions, and first aid recommendations. An MSDS is available on request. Avoid overexposure. All mixing and spraying must be conducted with adequate ventilation and proper personal protective equipment as recommended. Obtain medical care in case of extreme overexposure. For emergency medical information call DeSoto and Desoclean are trademarks of PRC-DeSoto International, Inc., registered with the U.S. Patent Office. All recommendations, statements, and technical data contained herein are based on tests we believe to be reliable and correct, but accuracy and completeness of said tests are not guaranteed and are not to be construed as a warranty, either expressed or implied. User shall rely on his own information and tests to determine suitability of the product for the intended use and assumes all risks and liability resulting from his use of the product. Seller s and manufacturer s sole responsibility shall be to replace that portion of the product of this manufacturer which proves to be defective. Neither seller nor manufacturer shall be liable to the buyer or any third person for any injury, loss, or damage directly or indirectly resulting from use of, or inability to use, the product. Recommendations or statements other than those contained in a written agreement signed by an officer of the manufacturer shall not be binding upon the manufacturer or seller. Printed in U.S.A. Issued February Supersedes March DeSoto Aerospace Coatings PRC-DeSoto International, Inc San Fernando Road, PO Box 1800 Glendale, California (818) Fax (818) (Formerly Courtaulds Aerospace, Inc.)