CoatingsPro Magazine

MAY 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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COATINGSPRO MAY 2015 75 delamination, Area No. 2 exhibited coating loss and delamination, Area No. 3 was in the process of being painted over an existing green coating, Area No. 4 exhibited coating loss and delamina- tion, and Area No. 5 was fnished on a new surface. Surface Profile Analysis Te surface profle from behind the delaminated coating was analyzed utilizing a Pro Scope 50x hand-held microscope to photograph and confrm the surface profle of the painted surface. It was reported that the school was painted several times before, and it is most likely that the existing coatings were just painted over. Te stereomicroscopy revealed several areas that appeared to be relatively glossy with uneven and dirty painted surfaces with no signs of abrasive surface preparation. Photo 2 shows the cond ition of A rea No. 2 dur ing sur face prepara- tion. It was repor ted by our c lient that the ha l l was delaminating. T he v isua l inspection showed no sig n of abrasive preparation of a pre- ex ist- ing coating , which is schedu led to be painted over and which appears to ex hibit a glossy and d ir t y sur face. Photo 3 shows the cond ition of A rea No. 3 dur ing paint application, show ing what appeared to be a glossy and d ir t y sur face w ith no sig n of abrasive sur face preparation. Gloss Measurements Gloss measurements were taken utiliz- ing a Novo-Gloss statistical gloss meter following ASTM D 523 method. Te gloss measurements were taken on the surface from behind the delaminated coating at 60 degrees. Basic classifca- tion of gloss taken at 60 degrees are as follows: Flat 0–15, Eggshell 5–20, Satin 15–35, Semi-Gloss 30–65, and Gloss 65–100. It should be noted that the surface areas tested were relatively uneven, which can reduce the overall gloss measurements. Te results for each area tested are as follows: Area No 1: 17.2 Area No. 2: 15.7 Area No. 3: 7.3 Area No. 4: 18.1 Area No. 5: N/A. Adhesion Evaluation by Knife Test Method Te adhesion evaluation was performed by the knife test method per ASTM D 3359. Te primary coating was tested in each area. Te results are determined by a set scale: 5 A No Loss, 4 A Trace Loss, 3 A 1/16 inch (0.2 cm) along X Cut, 2 A 1 inch (0.6 cm) along X Cut, 1 A Loss of most of the X Cut, and A 0 Loss Past X Cut. Te results of our tests are as follows: Area No. 1: 0 A Area No. 2: 0 A Area No. 3: 4 A Area No. 4: 0 A Area No. 5: 2 A Laboratory Analysis Te laboratory analysis consisted of further examination of coating samples retained from Areas No. 1, No. 2, and No. 4 during the onsite inspection that took place. Te retained samples consisted of delaminated coating samples from each area when applica- ble. Visual and stereomicroscopy were performed on the samples to document the conditions of the samples. Te primary fndings of the analysis The coating application appears to exhibit an inconsistent coating thickness that does not appear to meet the manufacturer's application recommendations for best performance. Photo 2. This photo shows Area No. 2, which exhibited coating loss and delamination. The visual inspection showed no sign of abrasive preparation of a pre-existing coating, which appears to exhibit a glossy and dirty surface. Elementary School Coatings Failures

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