Q: Why does my zipper fail a salt spray corrosion test?
Salt spray results depend on the test duration, the coating and the preparation of the sample, so first confirm the test was run the way it was specified. A number without a method cannot be compared with another number.
- Confirm the test duration, salt concentration and temperature actually used against the agreed method.
- Check whether the sample was cleaned and how it was handled before the test.
- Note where corrosion starts: cut edges, threads, or the coating face.
- Compare the failed part with the maker's reference sample for the same finish.
- Run a shorter and a longer exposure in parallel to see how fast the failure develops.
A result close to the agreed limit is a finish question, while a part that fails within a small fraction of the specified hours suggests a coating or process escape. Report the method, duration and photographs with the claim, because salt spray figures without a method are not comparable.