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Hours of Salt spray test requirements

We manufacture luminaries. For indoor applications, we use cold rolled steel sheet and for outdoor application, Die-casted and/or extruded aluminum.

We would like your guidance for the industry wide required number of hours for test results for our indoor and outdoor luminaries.

For instance, how many hours should we keep the luminaire body made of cold rolled steel sheet and a different luminaire made of aluminum in the salt spray of 5% salt and 95% water at temperature of 35 ± 2 degrees C ?

Best regards,

M. Shahkouhi
Luminaire Manufacturer - Dubai, UAE
2005

It will sound like I'm talking in circles, Mr. Shahhouhi, but the parts should be tested for however long your spec says they should survive :-)

The real problem is that the salt spray test is not easily used the way you would like it to be used. We all would like an accelerated test procedure to work like time-lapse photography and predict the life of finishes so we could use it as a design aid; instead, all it really does is subject different lots of parts to a repeatably abusive environment so that we can see if something went bad in the finishing process.

The way the problem really needs to be approached is to select a finish that experience shows will have a satisfactory life expectancy, and then use the salt spray test to insude that the coating that was actually applied was not deficient. Salt spray hours for anodized aluminum will often be 192 hours, and for powder coated finishes they might often be 500 hours. But that doesn't mean the powder coating will outlast the anodized aluminum.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005