50029

Testing a hardcoat anodize seal  

September 18, 2008

We have a customer that requires a sealed Type III harcoat anodize coating. We are using boiling DI water to accomplish this, and testing the seal using ASTM B136. Our problem is that our customer is testing incoming parts using a black permanent marker. They let the permanent ink sit on the surface for 1 - 2 minutes, then use an acetone-based nail polish remover to try and rub it off. If all the ink does not come off they reject the parts. Our stance is that if it passes the ASTM test it is a good part. Does anyone have any insight into using a permament marker for a seal test?

Jennifer Masse
Plating Shop Employee - Buffalo, NY

Jennifer

You do not say if you pass your customer's test sometimes or at all. If you pass only sometimes, you could have a process control issue. If you never pass, the test could be suspect.

However, if your customer has developed this test as acceptance criteria, you are stuck with it unless you can convince them that the B136 test is more appropriate. Even then, if I recall correctly, the test allows for variations in the test to simulate specific conditions.

Willie Alexander
- Colorado Springs CO

I have ever been asked to do the same seal test and never failed as long as it is acetone based. Even we passed a test requested by one customer using DI water.

John hu
- Singapore

Thanks for the response. We have had parts that pass the ASTM test but absorb some of the permanent marker (maybe about 10% of the area being tested shows black dye). We don't have an issue with testing or certifying to any standardized test the customer wants, but I cannot find anything that backs up a magic marker test.

Jennifer Masse
- Buffalo, NY