CoatingsPro Magazine

JUL 2015

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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66 JULY 2015 COATINGSPROMAG.COM Never Again P h o t o 1 . E x t e n s i v e d e l a m i n a t i o n o f a n i n s ta l led co at i n g ca u s ed by contamination of the surface prior to coatings application By D. Terry Greenfield, Principal Consultant with CorroMetrics Services, Inc. Photos courtesy of CorroMetrics Services, Inc. Surface Preparation Failures…or Maybe It's Really About Adhesion T here is an interesting suppo- sition enthusiastically propounded that sounds something like " 75 to 85 percent of all coatings failures are a result of improper surface preparation." Tis number, depending upon the source and author, can range from as low as 60 percent to numbers as high as 90 percent. Tis estimate (or "guessti- mate") has often intrigued me, because in my own experience, investigating coatings failures that have that sort of high percentage attributed to surface preparation doesn't seem to be supported, especially if we consider the amount of cleaning and preparation of the substrate required. Substrate Surface Preparation In any coatings project, the actual surface preparation of the substrate may account for 75 percent of the overall efort (including labor and materials), and that may be where this estimate of related coatings failures is guesstimated. Tere obviously is great opportu- nity to conceive a coating failure during the substrate surface preparation efort; many things can be improperly executed or missed. Preparing that initial surface can be thought of as constructing the foundation of a build- ing. No matter the efort exerted in the construction and aesthetic choices of the structure, it will ultimately only be as successful as the foundation it was built upon. If the foundation cracks, the building crumbles. So there is little argument that proper surface prepara- tion of the substrate along with correct selection of coatings for the environ- ment is a huge consideration. Te library of coatings failures attributed to improper surface prepara- tion of the substrate includes disasters resulting from contamination of the actual surface itself, which includes failure to remove oils and grease as well as dirt and other debris remaining on the surface before coating application; failure to remove non-visible contam- inates, such as salts; and improper Preparing that initial surface can be thought of as constructing the foundation of a building.

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