Q: How long should a salt spray test run on zipper sliders?
Duration is chosen to match the service environment and the customer specification. Neutral salt spray tests commonly run for 24, 48, 96 or 240 hours, with longer exposures for marine and automotive parts. The test uses a salt solution at a controlled concentration and pH, at a controlled chamber temperature, with the specimens positioned at a defined angle so that condensate does not pool on them.
For a zipper, test the slider, the teeth and the pull as assembled, and include the tape if you want to see staining from corrosion products. Prepare the surface as specified, and do not touch the test area. Chamber temperature, salt concentration, pH, collection rate and specimen angle are all fixed by the method, so quote them with the result and refer to the standard text for the values.
Report the hours, the method and the observed corrosion: the area affected, whether it is white or red rust, and whether it appeared at an edge, a scratch or a contact point. Acceptance is normally written as no red rust and no more than a defined area of white corrosion after the specified hours.