What the life depends on
The main factor is zinc thickness: thicker lasts longer because zinc is sacrificial—it corrodes in place of the steel.
Next come the chromate type/thickness and the environment—dry indoors is worlds apart from coastal salt air.
What salt spray tells you
The salt-spray test (ASTM B117) accelerates corrosion with a salt-fog chamber and records hours to white rust (zinc) and red rust (steel).
A figure like “72 h to red rust” is a lab comparison, not a number of years in service—but it compares quality between jobs well.
How to last longer
- Increase zinc thickness.
- Pick a darker chromate (yellow/green) over white-blue.
- Add a top coat/sealer for high salt-spray targets.
- For very harsh duty, consider a tougher coating system—ask our team.
FAQ
How many years will zinc last?+
No fixed number—it depends on thickness and environment; indoor parts last far longer than outdoor/salt-air ones.
Does 72 h salt spray equal X years?+
No direct conversion—it is an accelerated lab figure for comparing quality, not real service life.
Can you target a salt-spray rating?+
Yes—tell us the goal and we design zinc/chromate/sealer to pass, then verify by test.
