FIELD TESTING AT PANAMA CITY 



During the week of 10-14 March 1975, a cooperative field test was 

 conducted with the Naval Coastal Systems Laboratory, Panama City, Florida. 

 The test site was located in St. Andrews Bay, an inlet of the Gulf of 

 Mexico. The experiment was conducted on a platform located about 

 20 feet underwater and about 20 feet from an NCSL pier facility. The 

 temperature of the water was about 65 F (18.3 C) . The experiment was 

 conducted to (1) compare ease of application of two underwater -applied 

 formulations with each other under laboratory-controlled conditions, (2) 

 compare ease of application of underwater -applied paints to sandblasted 

 and wirebrushed steel specimens and to vertically and horizontally 

 placed steel specimens, and (3) field test the NCSL-developed coating 

 applicator. 



Experimental specimens 2 feet by 2 feet by 1 /4 inch were prepared 

 from rusty, mild steel plates either by sandblasting in an NCSL shop 

 prior to immersion or by wirebrushing underwater (Figure 5). The sand- 

 blasted finishes were no better than a Steel Structures Painting Council 

 Surface No. 6 (Commercial Blast Cleaned Surface Finish); wirebrushing 

 underwater was accomplished by a diver using a hydraulically powered 

 wirebrush (Figure 6). 



The underwater surface preparation and the material applications 

 were accomplished by different two-man teams; in all cases, the team 

 consisted of an NCSL-civilian diver and a military diver. A curved, 

 plastic applicator (Figure 7), designed and fabricated by NCSL, was used 

 to coat the steel specimens. A portion of coating was poured onto the 

 steel and then spread with the applicator. 



Experiments on individual specimens (see Figure 8, for example) are 

 described in detail below and then summarized in Table 6 for easy 

 comparison: 



Speo-imen 1 . A rusted panel was secured in a horizontal position 

 and wirebrushed underwater. The 101-2 formulation was somewhat difficult 

 to apply underwater with the curved plastic applicator. A metal pressure- 

 feed system (Figure 9) was used with Specimens 1 and 2 to place portions 

 of the coating on the steel before being spread with the applicator. 

 The equipment was quite messy to clean up, so with subsequent specimens 

 the coating was poured directly from the can onto the steel. 



Specimen 2. A sandblasted, horizontally held steel panel was 

 coated with some difficulty with the 101-2 formulation. It was a 

 little easier to coat than the Specimen 1 panel. 



Specimen S. A rusted panel was secured in a vertical position and 

 wirebrushed underwater. It was extremely difficult to coat it with the 

 101-2, and, consequently, only about half of it was coated. 



Specimen 4. A sandblasted, vertically held steel panel was coated 

 with extreme difficulty with the 101-2 formulation. It was almost as 

 difficult to apply as with Specimen 3. Consequently, only about three- 

 quarters of it was coated. 



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