465 MISCELLANEOUS COATINGS FOR METAL (STEEL)
From MDOT Policy Manual
- Furnish and apply various coatings to metal surfaces as specified. Refer to Sections 435 and 436 for cleaning and painting new and existing bridge structural steel, respectively.
Paint System C 912.05 Fusion Bonded Epoxy Powder Coating for Steel 917.02 Fusion Bonded Polyester Powder 917.03 Hot Dip Galvanized Zinc A 123, A 153, and 465.03.05(c) Galvanizing Repair A 780 and 465.03.05(c)
- Use paint and powder coating material selected from the Qualified Products List (QPL).
- Perform cleaning and coating in an approved, environmentally controlled plant. The AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. shall have access to each part of the process and reserves the right to witness or perform any Quality Control testing on a random basis.
- Use polyester powder coating when coatings other than paint are specified for steel, or as directed.
- The powder coating applicator shall have demonstrated the ability to properly apply and cure the materials of the system and shall be on the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.’s Approved List of Applicators prior to application of any coatings. Galvanizers shall be on the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.’s Approved List of Galvanizers.
- 465.03.01 Nongalvanized Carbon Steel. Prepare steel metal surfaces as specified in 436.03.10(h). Clean all items to be coated of any oil or grease; and abrasive blast to Near White in accordance with SSPCSociety for Protective Coatings-SP 10. Remove weld spatter, slivers, hackles, or other defects. Protect cleaned surfaces from high humidity, rainfall, and surface moisture; and do not allow to flash-rust. Ensure that the blast profile is 2 to 3 mils as per D 4417, Method C.
- (a) Epoxy Powder Coating System. The system consists of a single coat of epoxy powder coating. Ensure that the thickness of the cured coating is 7 ± 2 mils when measured as specified in SSPCSociety for Protective Coatings PA2.
- (b) Polyester Powder System. The system consists of Coat I of System C and a TGIC (Triglycidyl Isocyanurate) polyester powder finish coat. Apply the polyester powder in accordance with the manufacturer’s recommendation and in an operation that immediately applies the powder after the organic zinc rich primer has fully cured. Ensure that the dry film thickness of the organic zinc rich paint is 3 to 5 mils and the thickness of the cured polyester coating is 5 to 9 mils as specified in SSPCSociety for Protective Coatings PA2.
- 465.03.02 Hot Dip Galvanized Carbon Steel. Metals that have reactive steel chemistry require the galvanizer to reflect the steps to be taken to ensure proper adhesion in their quality control plan as per B 571.
- Ensure that the finished galvanized product is free of excessive zinc areas, weld spatter, slivers, ash, and dross or other detriments. Paint or powder coat hot dip galvanized steel as specified. Use an anti-out-gassing type powder coating material for galvanized items. Galvanized items shall not have been galvanized more than one month prior to coating and shall not have been water or chromate quenched.
- Clean and smooth surfaces to be coated by sweep blasting as per D 6386. Store items to be coated in an environment free of moisture and dust for a period of 12 hours maximum, when coating application does not immediately follow the sweep blast surface preparation.
- (a) Paint System. Ensure that all paint within the paint system is from the same manufacturer and that intermediate and finish coats conform to Coats II and III of System C, respectively. Apply all coatings using methods and under conditions recommended by the paint manufacturer. Measure the thickness of the coating as specified in SSPCSociety for Protective Coatings PA2.
- (b) Polyester Powder Coating System. Place prepared surfaces in a preheated oven and heat for the necessary amount of time. Out-gas galvanized metal surfaces by preheating the surfaces to a temperature 50 F greater than the cure temperature; but not exceeding a surface temperature of 390 F.
- Follow the powder coating manufacturer’s’ instructions in regards to the metal surface temperature, applying the coating material, and maintaining the cure parameters.
- Apply the powder electrostatically and cure at a temperature not to exceed 50 F less than the out-gas temperature immediately after out-gassing, then cool the preheated piece to 50 F less than the out gas temperature. Galvanized surfaces for items with different thicknesses shall be allowed to cool to at least 50 F below the out gas temperature prior to the application of the powder. The thickness of the polyester coating shall be 5 to 9 mils when measured in accordance with SSPCSociety for Protective Coatings PA2.
- 465.03.03 Adhesion. Adhesion of the paint or powder coating system to either bare or galvanized metal shall be at least 4 A when tested in accordance with D 3359, Method A.
- 465.03.04 Testing. The paint and powder coat finished surfaces shall be holiday and pinhole free when tested with a low voltage holiday detector (minimum 67 1/2 volts) in conformance with D 5162. There shall be no more than one deficiency per 5 square feet. Repair all holidays detected with additional coating.
- Visually inspect all items for blisters, sags, and other deficiencies and repair in conformance with 465.03.05, if required. Damaged or deficient areas shall not exceed ½ of 1 percent of the surface area of the item. Items requiring repairs exceeding 1 in. in the narrowest dimension shall be rejected.
- 465.03.05 Touch Up System. 436.03.24. Provide a compatible touch up system to repair defects, areas damaged during erection, and all visible open areas. Prepare areas to be repaired and apply touch up systems in accordance with the coating manufacturer’s recommendations.
- (a) Select the epoxy powder touch up material producer from the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.’s Approved List.
- (b) Polyester powder touch up system shall be a two component aliphatic polyurethane meeting 912.04.02. The coating thickness of the touch up material for powder coating may be applied in multiple coats and shall be the same thickness as the powder coating. Use Coat I of System C to repair damage to the coating that penetrates to the metal surface; followed by the polyurethane.
- (c) Make any necessary repairs to the galvanizing in accordance with A 780, using the hot stick or metalizing method. Use Coat I of System C for repairing the galvanizing if it is to be powder coated.
- 465.03.06 Color. The color of all coatings and touch up systems shall match Federal Standard 595 and the following as specified:
COLOR COLOR NO. Brown 20040 Black 27038 Green 24108
- 465.03.07 CertificationA document which verifies that the material and work complies with the applicable specifications and includes the actual test results to confirm the statement. The contents of the certification shall be on the Contractor's/vendor's/manufacturer's letterhead or approved document and shall be duly signed by a company officer. Certifications for metal products, when required, shall include a statement that the material was melted and manufactured in the United States except as provided in Section 165 of the Surface Transportation Assistance Act of 1982, as amended by Section 1041(a) and 1048(a) of the Intermodal Surface Transportation Efficiency Act of 1991 with regard to the furnishing and coating of iron and steel products. A nationwide waiver for this provision has been granted for pig iron and processed, pelletized, and reduced iron ore.. Paint shall meet 912.01.03, epoxy powder coating shall meet 917.02.02, and polyester powder coating shall meet 917.03.04.
- The acceptance of hot dip galvanized zinc will be based on inspection and shall meet A 123, A 153, and the Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof.
465.04 MEASUREMENT AND PAYMENT.
- Coatings for metal will not be measured but the cost will be incidental to the pertinent items specified.