Summary for salt spray hours for zinc plating Discussion
Standard salt spray hours for zinc plating is the core question here: Pat Donlon asks whether there is a universal red-rust requirement for zinc plate .0004-.0006" with yellow chromate per ASTM B633 Type II, SC3 and Macdermid JS 500 Ultraseal, as well as 5 µm zinc with yellow or bright chromate. The answer from the source says there is no known universal standard for salt spray hours before red rust, and points readers to other related threads for more information. Because the excerpt is truncated, no specific hour requirement or definitive pass/fail value is given. The practical takeaway is that salt-spray performance depends on the exact coating system and specification, so the thread does not establish a single standard number.
Q. Is there a standard on how many salt spray hours before red rust. I am looking particularly for Zinc Plate .0004-.0006″ Plus Yellow Chromate per ASTM B633 TY2, SC3, Plus Macdermid JS 500 Ultraseal. Zinc Plate 5 Micrometers Min, Yellow Chromate per img loading=”lazy” src, TY II, SC. 1. And, Zinc Plate 5 Micrometers Min, Bright Chromate per ASTM B633, TY III, SC. 1
Pat Donlon
plating shop – Rochester, New York
2003
A. Hi, Pat. I don’t know of a universal standard for this, but we have many threads on line that will provide some info. For example, letter 46231 implies that 120 hours to white rust and 240 hours to red rust is easily achievable with 8 microns (about .00032″).
Several threads here suggest that if you are aiming for much more than that, switching to a zinc alloy plating may be a more productive route than thickening the plating, and tweaking the chromate and final seal. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
October 17, 2009
Q. How many hours salt spray test of Ep-Fe/Zn 5 /CM2?
1. White rust?
2. Red rust?
Panya C
– Rayong, Thailand
February 12, 2013
A. Hi cousin Panya. Please introduce yourself and flesh out your situation. Our readers often won’t respond to abstract “flash-card” questions because they learn nothing in return for their effort, they rarely can be answered well with no circumstances offered, plus it can put them on the defensive against unknown parties (“well, your answer doesn’t agree with what our vendor told us”). Thanks for your understanding!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
February 13, 2013