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. ASTM Designation: A (American Standard Testing Method). Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings.
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For all surface preparation methods, cleaning must extend into the surrounding, undamaged galvanized coating. When it comes to repairing galvanized steel in the field, there is no limitation to the size that can be repaired.
Anyone making use of this information assumes all liability arising from such use. The method and extent of surface preparation shall be mutually x780 to the contracting parties.
ASTM AZinc Dust in Paint | American Galvanizer’s Association
For best results, thickness measurements for the metallized coating should be taken with either a magnetic aa780 an electromagnetic gauge. Apply the paint as recommended by the paint manufacturer in a single application employing multiple spray passes to achieve a dry film thickness to be agreed upon between the contracting parties.
Experience shows that in general organic zinc-rich systems are more tolerant of surface preparation. 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. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. The information provided herein is not intended as a representation or warranty on the part of the AGA.
Brite Zinc is an organic zinc compound. Zinc Spray Metallizing Astj spray, or metallizing, is done by melting zinc powder or zinc wire in a flame or electric arc and projecting the molten zinc droplets by air or gas onto the surface to be coated. Where such contaminants are found, the surface preparation standards associated with all repair materials require the removal of visible dirt, oil and grease deposits using a solvent cleaning method such as SSPC-SP1 Solvent Cleaning.
Surface profiling for abrasive blast cleaned surfaces may be performed using any method listed within ASTM D visual comparator, surface profile depth micrometer, or replica tape.
Authored by Alana Hochstein.
Touch-up materials are required to meet a coating thickness of at least 2. For power tool cleaned surfaces, a surface profile depth micrometer is the appropriate method for confirming profile, unless otherwise agreed. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application.
Any dust or loose residue from cleaning must be brushed away using a stiff-bristle brush or blown off using clean, dry air. This practice describes methods that may be used to repair damaged hot-dip galvanized coatings on hardware, structural shapes, and other products fabricated prior to hot-dip galvanizing, and uncoated areas remaining after initial hot-dip galvanizing.
Appropriate grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize abrasive cloths, discs, wheels or flaps. Surface Preparation Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning.
The practice is the same, but there are more restrictions to the allowable repairs on a new product than one that has been in service. Effective May 1st The zinc coating is difficult to damage, and field fabrication that requires removal of the coating should be minimized as much as possible.
Zinc spray, or metallizing, is done by melting zinc powder or zinc wire in a flame or electric arc and projecting the molten zinc droplets by air or gas onto the surface to be coated.
Ensuring Conformance to ASTM A | American Galvanizer’s Association
Watch the Videos The main restriction in the specification for repairing newly galvanized q780 is the size of the area which satm outlined in the product galvanizing specifications: Historical Version s – view previous versions of standard. The practice for repairing the galvanized coating in-field is the same as a80 practice for repair at the galvanizing facility, but there are more restrictions to the allowable repair size while at the galvanizing facility.
Within the text of this specification and where appropriate, SI units are shown in brackets. Zinc-based solder products closely match the surrounding zinc and blend in well with the existing coating appearance.
This abstract is a brief summary of the referenced standard. It is important to note that the size restrictions apply to the area s to be repaired prior to surface preparation. Corrosion resistance and service performance are very dependent on the properties of the paint system, the extent of surface preparation, and skills of individual applicators.
ASTM A contains three acceptable methods of touch-up and repair of hot-dip galvanized steel: Call for more information. The six-part video series will provide highly beneficial visual aids to those needing assistance with aatm the requirements of ASTM A There is no ASTM specification which specifies a maximum allowable repair size for galvanized items already accepted and delivered.
The specification explains how to use the z780 repair methods as well as the required coating thickness for the repaired area.
In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer astj be well versed in the equipment, materials and surface preparation standards required of each repair method. Ensure a blotter test is performed prior to using a compressed air source in accordance with ASTM D Contact Us Order Status.
Repairing HDG Steel
Topics will include proper equipment and materials to use while performing the process, explanation of the specifications to follow, and examples of best practice during application of the repair materials. Paints containing zinc dust are classified as organic or inorganic, depending on the binder they contain.
The area being repaired needs to be preheated to approximately F C. When ready to perform mechanical cleaning, check the surface preparation standard for a70 on the allowable tooling methods. Do not immediately apply repair materials over a freshly cleaned surface. Where circumstances do not allow blast cleaning, it is permissible to power disk sand areas to be repaired to bright metal.