1. Scope
1.1 This specification covers a group of inorganic zinc primers which can protect steel during the fabrication process, permit welding to specification requirements, and be overcoated.
1.2 The major pigment component in this coating is zinc dust, and the binder is inorganic.
1.3 This specification defines the minimum compositional and laboratory performance requirements for characterizing a group of zinc primers. It is to be used in conjunction with SSPC-PS Guide 22.00, “Guide for Selecting One-Coat Preconstruction or Prefabrication Painting Systems,” SSPC-PS Guide 12.00, “Guide for Selecting Zinc-Rich Painting Systems,” and with other SSPC specifications covering surface preparation, applications, thickness, inspection, and safety.
2. Description
2.1 GENERAL:
2.1.1 The zinc primers described in this specification consist of zinc dust, an inorganic vehicle, and selected additives, as required.
2.1.2 This specification covers inorganic zinc primers which are used as preconstruction primers. Frequently the primer is applied by an automatic process to steel plate. Once applied, the zinc primer need not be removed. It can be welded through, touched-up, and overcoated prior to being placed in service.
2.2 PIGMENTATION:
2.2.1 The major pigment component in these coatings is zinc dust of the type described in ASTM D 520.
2.2.2 Other pigment components may include welding enhancers, curing aids, tinting colors, suspension, and pot life control agents.
2.3 VEHICLE TYPES:
2.3.1 Water-reducible self-curing vehicles, including water soluble alkali metal silicates, quaternary ammonium silicates, phosphates, and modifications thereof. These coatings dry by evaporation of water and cure by chemical reaction to yield water-insoluble films.
2.3.2 Solvent-reducible self-curing vehicles, including ethyl and other organic silicates, polymeric modifications of these silicates and titanates. These systems are dependent upon moisture in the atmosphere to complete hydrolysis to yield an insoluble film.
2.3.3 Other organic vehicle components may be included but should constitute only a minor part of the total vehicle.
2.4 VOLATILE ORGANIC COMPOUND (VOC) CONTENT:
The VOC content of the primer shall be determined from the content of coating as applied, after recommended thinning.
