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Standards for crosshatch paint loss

Q. I am a QA inspector in the aluminum boat industry, and I am wanting to know what is the rule of thumb for pass/fail on crosshatch testing? (example; there are 24 squares, how many squares lost justifies pass/fail)?

Julie Schlipp
QA inspector - Lebanon, Missouri
October 20, 2008

A. Here are two articles worthy of your evaluation:
https://web.archive.org/web/20090106120708/https://www.decorativeresins.com/StrengthOfPaintReport.pdf
www.proinexinstruments.com/technicky_list/Cross_Hatch_Test.pdf
The second I think is more informative as it shows images of results after removing the tape and allocates an agreed code to the resultant damage.
However, the interpretation of the cross hatch test totally depends upon the expertise of the person carrying out the tests.

There appears to be no general set standard for what is classed as a pass or failure.
The ASTM D3359 is only a method, it is then up to the client to specify at what level/percentage of squares removed they will accept before the coating is classed as a failure. Alternatively, produce your own spec from data you have collected.

Terry Hickling
Birmingham, United Kingdom

Ed. update Sept. 2023: unfortunately that proinexinstruments.com domain no longer exists and was never archived by the Wayback Engine at archive.org.
www.proinex.cz is live, but it is not in English and does not appear to have any library articles.