(10) Glass Flake Polyester . No test data was found concern- 

 ing the protective ability of this coating for steel piling. However, it 

 was reported to be the best of a member of coatings tested for the pro- 

 tection of ship bottoms (Devoluy, 1965). Better resistance to abrasion 

 and undercutting were claimed for this coating relative to others tested. 

 Based on the above findings, it is felt that this coating may have some 

 merit in protecting steel piling, especially in the sand abrasion zone. 



(11) Furan . Four protective coating systems involving fuxan 

 have been tested on bare steel for periods up to 10 1/2 years : Formula 

 117 pretreatment primer plus vinyl red lead, iron oxide primer, flame- 

 sprayed zinc, and flame-sprayed aluminum. Of these systems, furan over 

 flame-sprayed zinc has given good protection for 10 1/2 years (Alumbaugh 

 and Brouillette, I966). Furan 's performance when applied over the other 

 coating materials and applied on bare steel has been fair in comparison 

 to other coatings tested. See Figures 11a, lie and 12. 



c. Surface Preparation for Coatings . The proper preparation 

 of the metal surface is of primary importance when applying a protective 

 coating of steel piling. Metal surface preparation methods include blast 

 cleaning, pickling, solvent cleaning, hand tool cleaning, power tool 



cleaning and flame cleaning. 



Blast cleaning is commonly used in the surface preparation of steel 

 piling when significant quantities are involved. Although varying degrees 

 of surface blast cleaning are used, a surface blasted to white metal can 

 be expected to give best results. Blast cleaning to this extent, however, 

 is usually not economical for many structures. Commercial blast cleaning 

 which requires the removal of all oil, grease, mill scale, rust, and other 

 surface contaminants is considered adequate for many of the protective 

 coating systems. 



Pickling is another method of metal surface preparation which pro- 

 motes relatively long paint life for most coatings, when the proper 

 procedures are used (Steel Structure Painting Council, Volume 2, 196h) . 

 However, facilities for pickling large structural items are rather 

 limited. 



Solvent cleaning, hand tool cleaning, power tool cleaning, and 

 flame cleaning may also be used to prepare steel pile surfaces for 

 coating. These methods are considered to be more limited in use and 

 effectiveness than blast cleaning or pickling. 



Specifications and details concerning the various metal surface 

 preparation methods and their uses are contained in a report by the 

 Steel Structures Painting Council, Volumes 1 and 2, (196^1). 



d. Primers for Steel Piling . Specially formulated coatings 

 known as primers are often applied to bare metal surfaces before other 

 coatings are applied. Prerequisites for maximum performance of primers 

 as given in Jarboe {l96h) are as follows: 



34 



