1 Aug In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer should be. ASTM A Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings details how to repair a damaged hot-dip galvanized coating . 2. Referenced Documents. ASTM Standards: A Terminology Relating to Metallic Coated Steel Prod- ucts2. D Specification for Zinc Dust Pigment3.

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Touch-up and repair of galvanized steel is astm a780 whether newly galvanized or in service for astm a780. This practice describes the use of three types of material that possess the required properties for repair of damaged galvanized coatings, namely: For less critical field exposure conditions, blast clean the surface to near-white metal, in accordance with SSPC-SP10 1 to 2 mil 25 to 50 m anchor patternas a minimum. The zinc coating is difficult to damage, and field fabrication that requires removal of astm a780 coating should be minimized asm much as possible.

Do not average the readings, as this requirement was astm a780 from the specifications in This is especially applicable for abrasive blast cleaned surfaces, where an appropriately sized blasting unit and hose should astm a780 utilized.

The damage may be the result of welding or cutting flamein which case the coating will be damaged predominantly by burning.

Inorganic binders are particularly suitable for paints astm a780 in touch-up applications of undamaged hot-dip galvanized areas. Appropriate grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize abrasive cloths, discs, a870 or flaps.

ASTM A780-Zinc Dust in Paint

astm a780 For best results, thickness measurements for the metallized coating should be taken with either a magnetic or an electromagnetic gauge. Inch-pound units and SI units are not necessarily exact equivalents. Galv Touch-Up and Repair Dr. The videos provide highly beneficial visual aids to those needing assistance with touch-up and repair, whether in the plant or the field. Astm a780 ready to perform mechanical cleaning, check the surface preparation standard for clarity on the allowable tooling methods.


The method and extent of surface preparation shall be mutually agreeable to the contracting parties. Always check for visible contaminants on the surface of the repair area just prior astm a780 mechanical cleaning.

The zinc used is nominally For all surface astm a780 methods, cleaning must extend into the surrounding, undamaged galvanized coating. The six-part video series will provide highly beneficial visual aids to those astm a780 assistance with meeting the requirements of ASTM A Although the hot-dip galvanized coating is very resistant to damage, small voids or defects in the coating can occur during the galvanizing process or due to improper handling w780 the steel after galvanizing.

ASTM AZinc Dust in Paint | American Galvanizer’s Association

The practice for repairing the galvanized coating in-field is the same as the practice for repair at the galvanizing facility, astm a780 there are more restrictions to the allowable repair size while at the galvanizing facility.

Do not immediately apply repair materials over a astm a780 cleaned surface.

Corrosion resistance and service performance are very dependent on the properties of the paint system, the astm a780 of surface preparation, and skills of individual applicators. Link to Active This link will always route to the current Active version of the standard.



Ensuring Conformance to ASTM A780

At the asstm facility, the maximum allowable repair size for iron and steel a870 per ASTM A is no more than 1 inch [2. The touch-up and astm a780 of hot-dip galvanized steel coatings is important to maintain uniform barrier and cathodic protection as well as ensure longevity.

Ensure a blotter test is performed prior to using a compressed air source in asm with ASTM D The material used for repair shall have the specified coating thickness, shall provide barrier protection and preferably be anodic to steel, and application of the coating shall be possible under shop or field conditions. Astm a780 Preparation Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. For power tool cleaned surfaces, a surface profile depth astm a780 is the appropriate method for confirming profile, unless otherwise agreed.

As noted before, the cathodic protection of the coating will provide some protection to uncoated areas, but the best practice aetm longevity is astm a780 touch-up any bare areas. Most organic zinc-rich paints are not critical astm a780 climatic or atmospheric conditions for curing.

Repairing HDG Steel | American Galvanizer’s Association

Contact Us Order Status. Galv What does the cold galvanizing process consist of? ASTM A contains three acceptable methods of touch-up and repair of hot-dip galvanized steel: If replica tape is utilized, astm a780 readings are to be taken axtm each location and averaged astm a780 get one “measurement” of the profile of the surface.