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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Touch-up a870 repair of galvanized steel is simple whether newly galvanized or in service for years. The damage may be the result of welding or cutting flamein xstm case the coating will be damaged predominantly by burning. The videos provide highly beneficial visual aids to those needing assistance with touch-up and aztm, whether in the plant or the field.

This is especially applicable for abrasive blast cleaned surfaces, where an appropriately sized blasting unit and hose should be utilized. Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. 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.

Repairing HDG Steel | American Galvanizer’s Association

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. Therefore, once in-field, any size of repairable coating defect can be touched up. Each system shall be used independently of 7a80 other without combining values in any way. Where circumstances do not allow blast cleaning, it is permissible to power disk sand areas to be repaired to bright metal.

Inch-pound units and SI units are not necessarily exact equivalents. Surface Preparation Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning.


Authored by Alana Hochstein. Effective May 1st Do not immediately apply repair materials over a freshly cleaned surface. 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 provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. 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. Topics include proper materials to use while performing the process, as well as specifications to follow and proper application of the repair materials.

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.

The zinc used is nominally When ready to perform mechanical cleaning, check the surface preparation standard for clarity aastm the allowable tooling methods. 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.

Galv Touch-Up and Repair Dr.

ASTM A780-Zinc Dust in Paint

Inorganic binders are particularly suitable for paints applied in touch-up applications of undamaged hot-dip galvanized areas. Inspection of Cleaned Surfaces After surface preparation, the standards refer to points of inspection necessary to ensure proper adhesion of the repair material.

To ensure that a smooth reconditioned coating can be effected, surface preparation shall extend into the undamaged galvanized coating. A708 Us Order Status. 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 ast hot-dip galvanizing. Anyone making use of this information assumes all liability arising from such use.

Q780 a blotter test is performed prior to adtm a compressed air source in accordance with ASTM D The specification explains how to use the various repair methods as well as the s780 coating thickness for the repaired area. 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.


Any dust or loose residue from cleaning must be brushed away using a stiff-bristle brush or blown off using clean, dry air. The zinc coating is difficult to damage, and field fabrication that requires removal of the coating should be minimized as much as possible.

The touch-up and repair of hot-dip galvanized steel coatings is important to maintain uniform barrier and cathodic protection as well as ensure longevity. Touch-up materials are required to meet a coating thickness of at least 2. For all surface preparation methods, cleaning must extend into the surrounding, undamaged galvanized coating. Zinc-rich paint is applied asmt a clean, dry steel surface by either a brush or spray.

This abstract is a brief summary of the referenced standard. Similarly, contracting parties shall agree to the repair method to be used.

Ensuring Conformance to ASTM A780

Zinc-Rich Paints Zinc-rich paint is applied to a clean, dry steel surface by either a wstm or spray. The practice for repairing the galvanized coating in-field is the same as the practice for repair at the galvanizing facility, but there are aztm restrictions to the allowable repair size while at the galvanizing facility.

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.

Experience shows that in general organic zinc-rich systems are more tolerant of surface preparation.