ASTM A780 PDF
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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At the galvanizing facility, the asstm allowable repair size for iron and steel products per ASTM A is no more than 1 inch [2. The zinc used is nominally Brite Zinc meets and exceeds this percent. However, do not clean excessively beyond the area of repair. Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. Correct for the additional tape thickness i. A7880, a visual inspection to confirm the level of cleanliness must be carried out to ensure the standard is met.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Topics will include proper equipment and materials to use while performing the process, explanation of the specifications to follow, and examples of best practice 7a80 application of the repair materials.
The information provided herein is not intended as a representation or warranty on the part of the AGA. The material provided herein has been developed to wstm accurate and authoritative information about after-fabrication hot-dip galvanized steel.
This is especially applicable for abrasive blast cleaned surfaces, where an appropriately sized blasting unit and hose should be utilized. Requirements concerning the renovation of uncoated areas remaining after initial hot-dip galvanizing are contained within the applicable material specification.
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.
The damage may be the result of welding or cutting flamein which case the coating will be damaged predominantly by burning. 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. Touch-up materials are required to meet a coating thickness of at least 2.
Most organic zinc-rich aastm are not critical of climatic or atmospheric conditions for curing. For power tool cleaned surfaces, a surface profile depth micrometer is the appropriate method for confirming profile, unless otherwise agreed.
ASTM A780-Zinc Dust in Paint
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. Each system shall be used independently of the other without combining values in any way.
Zinc-Rich Paints Zinc-rich a78 is applied to a clean, dry steel surface by either a brush or spray.
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. Galv Touch-Up and Repair Dr. Galv Touch Up Methods Dr. The zinc coating is difficult to damage, and field fabrication that requires removal of the coating should be minimized as much as possible. After surface preparation, the standards refer to points of inspection necessary to ensure proper adhesion of the repair material.
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: 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.
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. Topics include proper materials to use while performing the process, as well as specifications to follow and proper application of the repair materials. 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.
Ensure a blotter test is performed prior to using a compressed air source in accordance with ASTM D Any dust or loose residue from cleaning must be brushed away using a stiff-bristle brush or blown off using clean, dry air. Experience shows that in general organic zinc-rich systems are more tolerant of surface preparation.
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.
The method and extent of surface preparation shall be mutually agreeable to the contracting parties. Appropriate grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize abrasive cloths, discs, wheels or flaps.
ASTM AZinc Dust in Paint | American Galvanizer’s Association
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 the galvanizing facility. Historical Version s – view previous versions of standard.
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. Hand tool cleaning with a stiff-bristle or nylon brush does not meet specification.
Call for more information. When ready to perform mechanical cleaning, check the surface preparation standard for clarity on the allowable tooling methods.
Brite Zinc is an organic zinc compound. This practice describes the use of three types of material that possess the required properties for repair of damaged galvanized coatings, namely: When it comes to repairing galvanized steel in the field, there is no limitation to z780 size that can be repaired.
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. It is important to note that the size restrictions apply to the area s to be repaired a708 to surface preparation.