Tag: hot dip
Requirements for powder coating over hot dip galvanizing
The following specification is recommended: Use zinc phosphate pretreatment if highest adhesion is required. Surface must be perfectly clean. Zinc phosphate has no detergent action and will not remove oil or soil. Use iron phosphate if standard performance is required. Iron phosphate has a slight detergent action and will remove small amounts of surface contamination. Best used for pre-galvanized products. Pre-heat work prior to powder application. Use ‘degassing’ grade polyester powder coating only . Check for correct curing by solventRead More …
Solutions for the problems of powder coating over hot dip galvanizing
1. Incomplete curing: Polyester powder coating powder is thermosetting resins that cross-link to their final organic form by being maintained at a temperature (typically 180 o C), for about 10 minutes. Curing ovens are designed to provide this time at temperature combination. With hot dip galvanized items, with their heavier section thickness, it is necessary to ensure that sufficient stoving time is allowed to meet the curing specifications. Pre-heating of the heavier work will assist in accelerating the curing processRead More …