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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Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. This practice describes methods that may be used to repair damaged atm galvanized coatings on hardware, structural shapes, and other products fabricated prior to x780 galvanizing, and uncoated areas remaining after initial hot-dip galvanizing.
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. The specification explains how to use the various repair methods as well as the required coating thickness for the repaired area. Any dust or loose residue from cleaning must be brushed away using a stiff-bristle brush or blown off using clean, dry air.
Link to Active This link will always route to the current Active version of the standard. 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. Zinc spray, or metallizing, is done by melting zinc powder or zinc wire in a flame or electric x780 and projecting the molten zinc droplets by air or gas onto the surface to be coated.
ASTM AZinc Dust in Paint | American Galvanizer’s Association
Galv Touch-Up and Repair Dr. The zinc used is wstm It is informational only and atm an official part of the standard; the full text of the standard itself must be referred to for its use and application.
When ready to perform mechanical cleaning, check the surface preparation standard for clarity on the allowable tooling methods.
ASTM A contains three acceptable methods of touch-up and repair of hot-dip galvanized steel: For all surface preparation methods, cleaning must extend into the surrounding, undamaged galvanized coating.
Ensuring Conformance to ASTM A | American Galvanizer’s Association
Finally, a visual inspection to confirm the level of cleanliness must be carried out to ensure the standard is met. This is especially applicable for abrasive blast cleaned surfaces, where an appropriately sized blasting unit and hose should be utilized.
Inspector Listing – Non-U. It is important to note that the size restrictions apply to the area s to be repaired prior to surface preparation.
The damage may be the result of welding or cutting flamein which case the coating will be damaged predominantly by burning. 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. The zinc coating is difficult to damage, and field fabrication that requires removal of the coating should be minimized as much as possible.
To ensure that a smooth reconditioned coating can be effected, surface preparation shall extend into the undamaged galvanized coating. Surface profiling for abrasive blast cleaned surfaces aatm be performed using any method listed within ASTM D visual comparator, surface profile depth micrometer, or replica tape.
Most organic zinc-rich paints are not critical of climatic or atmospheric conditions for curing. Brite Zinc is an organic zinc compound. For less critical field exposure conditions, blast clean the surface to near-white axtm, in accordance with SSPC-SP10 1 to 2 mil 25 to q780 m anchor patternas a minimum.
Paints containing zinc dust are classified as organic or inorganic, depending on the binder they contain. A listing a7880 various manufacturers and products for the maintenance and repair of hot-dip galvanized structures is available for download.
Hand tool cleaning with a stiff-bristle or nylon brush does not meet specification. 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. Topics include proper materials to use while performing the process, as well as specifications to follow and proper application of the repair materials.
For power tool cleaned surfaces, a surface profile depth micrometer is the appropriate method for confirming profile, unless otherwise agreed. After surface preparation, the standards refer to points of inspection necessary to ensure proper adhesion of the repair material.
ASTM A780-Zinc Dust in Paint
The six-part video series will provide highly beneficial visual aids to those needing assistance with meeting the requirements of ASTM A Authored by Alana Hochstein. 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: Soldering is done with zinc-based alloys in either a stick or powder form.
Galv What does the cold galvanizing process consist of? 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. Within the text of this specification and where s780, SI units are shown in brackets. Effective May 1st