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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Correct for the additional tape thickness i. Galv What does the cold galvanizing process consist of? 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: The practice for repairing the galvanized coating in-field is the same as the practice for repair at the galvanizing facility, but there are more restrictions to the allowable repair size while at the galvanizing facility.
Brite Zinc is an organic zinc compound.
ASTM AZinc Dust in Paint | American Galvanizer’s Association
This abstract is a brief summary of the referenced standard. 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.
Where such contaminants are a80, the surface preparation standards associated with all repair materials require the removal of visible dirt, oil and grease deposits using a solvent cleaning method xstm as SSPC-SP1 Solvent Cleaning.
The area being repaired needs to be preheated to approximately F C. When ready to perform mechanical cleaning, check the surface preparation standard for clarity on the allowable tooling methods.
Appropriate grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize wstm cloths, discs, wheels or flaps.
Authored by Alana Hochstein. The six-part video series will provide highly beneficial visual aids to those needing assistance with meeting the requirements of ASTM A For all surface preparation methods, cleaning must extend into atm surrounding, undamaged galvanized coating.
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.
The method and extent of surface preparation shall be mutually agreeable to the contracting parties. Inch-pound units and SI units are not necessarily exact equivalents. Although some of the requirements within ASTM A are relatively straightforward, other a7880 related to surface preparation often require clarification. Paints containing zinc dust are classified as organic or inorganic, depending on the binder they contain.
Ensuring Conformance to ASTM A780
As noted before, the cathodic protection of the coating will provide some protection to uncoated areas, but the best practice for longevity is to touch-up any bare areas. Touch-up materials are required to meet a coating thickness of at least 2.
Where blast or power tool cleaning cannot be performed, hand tool cleaning per SSPC-SP2 Hand Tool Cleaning allows the use of wire brushing, scraping, chipping and sanding. The zinc used is nominally The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel.
For best results, thickness measurements for the metallized coating should be aa780 with either a magnetic or an electromagnetic gauge. The damage may be the result of welding or cutting flamein which case the coating will be damaged predominantly by burning.
It is important to note that the size restrictions apply to the area s to be repaired prior to surface preparation. Inorganic binders are particularly suitable for paints applied in touch-up applications of undamaged hot-dip galvanized areas. Topics include asrm materials to use while performing the process, as well as specifications to follow and proper application of the repair materials.
At the galvanizing facility, the maximum allowable repair size for iron and steel products per ASTM A is no more than 1 inch [2. Brite X780 meets and exceeds this percent. Any dust or loose residue from cleaning must be brushed away using a stiff-bristle brush or blown off using clean, dry air.
The videos provide highly beneficial visual aids to those needing assistance with touch-up and repair, whether in the plant or the field. If replica tape is utilized, two readings are to be taken over each location and averaged to get one “measurement” of the profile of the surface.
Where circumstances do not allow blast cleaning, it is permissible to power disk sand areas to be repaired to bright metal. Experience shows that in general organic zinc-rich systems are more tolerant of surface preparation. 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. To ensure that a smooth reconditioned coating can be effected, surface preparation shall extend into the undamaged galvanized coating.
Hand tool cleaning ast a stiff-bristle or nylon brush does not meet specification. It is informational only and astmm an official part of the standard; the full astk of the standard itself must be referred to for its use and application. Historical Version s – view previous versions of standard. Call for more information.
ASTM A780-Zinc Dust in Paint
Anyone making use of this information assumes all asm arising from such use. In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer should be well versed in the equipment, materials and surface preparation standards required of each repair method. However, do not clean excessively beyond the area of repair. There is no ASTM specification which specifies a maximum allowable repair size for galvanized items already accepted and delivered.
Maximum Allowable Repair Size The practice for repairing the galvanized coating in-field is the same as the practice for repair at the galvanizing facility, but there are more restrictions to the allowable repair size while at atsm galvanizing facility. Ensure a blotter test is performed prior to using a compressed air source in accordance with ASTM D This practice describes the use of three types of material that possess the required properties for repair of damaged galvanized coatings, namely: