49666

Types of finishes that can reach 200 hour salt spray. [Oregon] 

August 12, 2008

Our customer has asked for a finish that can reach a salt spray test of 200 hours.

Tom Hendrickson
job shop-manufacturer - Clackamas, OR, USA

Hi, Tom. I remember a science class where the teacher said "peas are that thing which, if you had a trillion of them, would cover the earth knee-high". The point was that it was a poor definition because countless things, rather than just peas, met the definition. There are countless coatings of every variety that will meet 200 hour salt spray. Other things must come into it: appearance, substrate, organic vs. inorganic, adhesion, etc. Please tell us what kind of parts you are speaking of, because dozens of different kinds of paints can achieve this rating before we even think about other finishing technologies. Thanks.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Thank you for the feedback. The material is drawing quality cold rolled steel. Currently using yellow zinc chromate SC3 type II Fe/Zn 12 per ASTM B633. Customer wants 200 salt spray. Does it make a difference if a hexavalent yellow or non-hexavalent yellow zinc is used for the results in a salt spray test? What are alternate coatings for this type of material?

Tom Hendrickson
- Clackamas, OR, USA