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January 14 - January 20, 2013
Is the MEK rub test a conclusive test to check the cure of IOZ coatings?
More items for
Quality Control
Selected Answers
From
Simon Hope of BIS Salamis (M&I) on
January 16, 2013:
MEK rub test is only subjective as proof of cure for IOZ coatings. The test is only valid for the actual area tested and can only be applied to the whole item by extrapolation of result. Confidence in the result can vary wildly, depending on time, humidity and temperature, as the curing mechanism of IOZ is totally dependent on the integration of water into the silicate precursor to create the matrix to support the metallic zinc. Hence, the best advice is that once touch dry, fresh water washing enhances the cure mechanism. High humidity and water washing will give confidence and MEK rub then gives verification.
From
wenbo chen of International Paint on
January 15, 2013:
Though ASTM D 4752 describes a standard test method for measuring MEK resistance of IOZ by solvent rub, we always use a coin test in the field. The MEK test is more likely a lab test.
From
Chuck Pease of PCG on
January 14, 2013:
Not conclusive, as Dave mentioned. Only a estimation. This requirement is per ASTM D 4752. Note that in the 4th paragraph, line 2, they call it an estimation.
From
Dipesh Vyas of CARBOLINE on
February 15, 2013:
My field expereince reveals that the coin test is the best, easiest,quickest most and reliable test to verify curing of spray- applied IOZ film. The MEK rub test, if not performed by a skilled person, can have misleading results because spray-applied IOZ always has some loose zinc dust ( overspray), and if not cleaned will react with MEK In first 5 passes, only satin will be noticed .
From
Tom Schwerdt of Texas Department of Transportation on
January 22, 2013:
Wenbo, the MEK rub is certainly a field test - all you need is a rag, MEK and a finger! (Okay, a glove would be nice to have, too.) The MEK rub is more conclusive than the coin test. The only truly conclusive test is in the lab - generally a force cure in a sealed vial, followed by gas chromatography.
From
Dave Lisnock of Arizona State University W.P. Carey Facilities on
January 14, 2013:
No, it is not a conclusive test. The only true test is a lab test.
From
Tom Schwerdt of Texas Department of Transportation on
February 19, 2013:
Dipesh - how crisp is the edge of your coin? How much force are you using? At what angle are you holding the coin? The coin test is at least as variable (if not more so) than the MEK rub test.
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Tagged categories:
Curing;
Performance testing
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