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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Experience shows that in general organic zinc-rich systems are more tolerant of surface preparation. Do not average the readings, as this requirement was removed from the specifications in August 1, Authored by Alana Hochstein.
ASTM AZinc Dust in Paint | American Galvanizer’s Association
Hand tool cleaning with a stiff-bristle or nylon brush does not meet specification. Inspector Listing – Non-U. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
The main restriction in the specification for repairing newly galvanized material is the size of the area which is outlined in the product galvanizing specifications:. Zinc spray, or metallizing, is done by melting zinc powder or zinc wire in a flame or electric arc and projecting aa780 molten zinc droplets by air or gas onto the surface to be coated. 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 of the steel after galvanizing.
Do not immediately apply repair materials over a freshly cleaned surface. Although some of the a708 within ASTM A z780 relatively straightforward, other requirements related to surface preparation often require clarification.
Correct for the additional tape thickness i. Zinc Spray Metallizing 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.
Repairing HDG Steel | American Galvanizer’s Association
Most organic zinc-rich paints are not critical of climatic or atmospheric conditions for curing. The method and extent of surface preparation shall be mutually agreeable to the contracting parties. At the galvanizing facility, the asstm allowable repair size for iron and steel products per ASTM A is no more than 1 inch [2.
Brite Zinc meets and exceeds this percent. Surface profiling for abrasive blast cleaned surfaces may be performed using any method listed within ASTM Aatm visual comparator, surface profile depth micrometer, or replica tape. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
A listing of various manufacturers and products for the maintenance and repair of hot-dip galvanized structures is available for download. Effective May 1st The zinc used is nominally The touch-up and repair of hot-dip galvanized steel coatings is important to maintain uniform barrier and cathodic ashm as well as ensure longevity.
Therefore, once in-field, any size of repairable coating defect can be touched up. As noted before, the cathodic protection of the aetm will provide some protection to uncoated areas, but the best practice for longevity is to touch-up any bare areas.
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.
This is especially applicable for abrasive blast cleaned surfaces, where an appropriately sized blasting unit and hose should be utilized. 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. Within the text of this specification and where appropriate, SI units are shown in brackets.
Watch the Videos The main restriction in the specification for repairing newly galvanized material is the size of the area which is outlined in the product galvanizing specifications: Anyone making use of this information assumes all liability arising from such use. The specification explains how to use the various repair methods as well as the required coating thickness for the repaired area. If replica tape is utilized, two readings are to be taken aetm each location and averaged to get one “measurement” of the profile of the surface.
Touch-up materials are required to meet a coating thickness of at least 2. This abstract is a brief summary of the referenced standard.
Inch-pound units and SI units are not necessarily exact equivalents. Historical Version s – view previous versions of standard. Always check for visible contaminants on the surface of the repair area just z780 to mechanical cleaning.
Ensuring Conformance to ASTM A780
The six-part video series will provide highly beneficial visual aids to those needing assistance with meeting the requirements of ASTM A This material provides general information only and is not intended as a substitute for competent adtm examination and verification as to suitability and applicability.
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.
Brite Zinc is an organic zinc compound. The information provided herein is not intended as a representation or warranty on the part of the AGA. Contact Us Order Status.