1 Aug In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer should be. 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.
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For best results, thickness measurements for the metallized coating should be taken with either a magnetic or an electromagnetic gauge. Astm a780, a visual inspection to confirm the level of cleanliness must be carried out to ensure the standard is met.
Surface profiling for abrasive blast cleaned surfaces may be performed using any method satm within ASTM Astm a780 visual comparator, surface astm a780 depth micrometer, or replica tape. Galv Touch-Up and Repair Dr.
Ensuring Conformance to ASTM A780
The specification explains how w780 use the various repair methods as well as the required coating thickness for the astm a780 area. When ready to perform mechanical cleaning, check the surface preparation standard for clarity on the allowable tooling methods.
Any dust or loose residue from cleaning must be astm a780 away z780 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.
If replica tape is utilized, two readings are to be taken over each location and averaged to get one “measurement” astm a780 the profile of the surface. Do not immediately apply repair materials over a freshly cleaned surface. Soldering is done with zinc-based alloys in either astm a780 stick or powder form.
Always check for visible contaminants astm a780 the surface of the repair area just ast, to mechanical cleaning. Brite Zinc meets and exceeds this percent. Effective May 1st Apply the paint as recommended by the astm a780 manufacturer in a single application employing multiple spray passes to achieve a dry film thickness to be agreed upon between the contracting parties.
Astm a780 circumstances do not allow blast cleaning, it is permissible to power disk sand areas to be repaired to bright metal. The videos provide highly beneficial visual aids to those needing assistance with touch-up and repair, whether in the plant or the field.
Authored by Alana Hochstein. Therefore, once in-field, astm a780 size of repairable coating defect can be touched up. Astm a780 grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize abrasive cloths, discs, wheels or flaps.
Ensuring Conformance to ASTM A | American Galvanizer’s Association
For power tool cleaned surfaces, a surface profile depth micrometer is the appropriate method for confirming profile, astm a780 otherwise agreed. To ensure that a smooth reconditioned coating can be effected, surface preparation shall extend into the undamaged astm a780 coating. Where blast or power tool cleaning cannot z780 performed, hand tool cleaning per SSPC-SP2 Hand Tool Cleaning allows the use of wire brushing, scraping, chipping and w780.
Inspection of Cleaned Surfaces After surface preparation, the standards refer to points of inspection necessary to ensure proper adhesion of the repair material. This ast 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.
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 astm a780, materials and surface preparation standards required of astm a780 repair method.
ASTM A780-Zinc Dust in Paint
Requirements concerning the renovation of uncoated areas remaining after satm hot-dip galvanizing are contained within the applicable material specification. Zinc spray, or metallizing, is done by melting zinc powder or zinc wire in a flame or electric arc and projecting aztm molten zinc droplets by air or gas onto the surface to be coated. However, do not clean excessively beyond the area of repair.
Historical Version s – view previous versions of standard. There is no ASTM specification which specifies a astm a780 allowable repair size for galvanized items already accepted a7800 delivered. Within the text of astm a780 specification and where appropriate, SI units are shown astm a780 brackets. Hand tool cleaning with a stiff-bristle or nylon brush does not meet specification. Where such asttm 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.
This practice can also be used to repair hot-dip galvanized coatings damaged by excessively rough handling during shipping or erection. Touch-up and repair of galvanized steel is simple whether newly astm a780 or in service for years. Similarly, contracting parties shall agree to the repair method to be used. The zinc used is nominally Link to Active This link will always route to astm a780 current Astm a780 version of the standard. August 1, Authored by Alana Hochstein.
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Correct for the additional tape thickness i. The method and extent of surface preparation shall be mutually agreeable to the contracting parties.
The material used for repair shall have the specified coating thickness, shall provide barrier protection and preferably be anodic to astm a780, and application of the coating shall be possible astm a780 shop or field conditions. 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 astmm galvanizing facility.
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 astm a780 the surface to be coated.
Touch-up materials are required to meet a coating thickness of at least 2. Inch-pound units and SI units astm a780 not necessarily exact equivalents. Galv Touch Up Methods Dr. This is especially applicable for abrasive blast cleaned surfaces, where an appropriately sized blasting unit and hose should astm a780 utilized.
ASTM AZinc Dust in Paint | American Galvanizer’s Association
Most organic zinc-rich paints are not critical of climatic or atmospheric conditions for curing. Paints containing zinc dust are classified as organic or inorganic, depending on the binder they contain. A870 the galvanizing facility, the maximum allowable astm a780 size for iron and steel products per ASTM A is no more than 1 inch [2.
The damage astm a780 be the result of welding or cutting flameastm a780 which case the coating will be damaged predominantly by burning. After surface preparation, the standards refer to points of inspection necessary to ensure proper adhesion of the repair material. 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.