Sherwin-Williams has unveiled a new marine coating that Navy testing has shown to save materials and labor, while fending off the dreaded “pinking” of ships coated in traditional haze gray silicone alkyds, the company says.
Using Sherwin-Williams’ Polysiloxane XLE-80 HAPS Free shaved coating and labor costs by 26%, when compared with usage of a silicone alkyd coating, according to “Time & Cost Savings Associated with the Application of MIL-PRF-24635 Type V Polysiloxane to the Freeboard of the USS Bonhomme Richard (LHD-6),” a presentation given in June at Mega Rust 2011 in Norfolk, VA.
|Sherwin-Williams’ Polysiloxane XLE-80 HAPS Free was applied to the USS Bonhomme Richard during a recent drydock maintenance period.|
The presentation was by Paul Slebodnick, of the U.S. Naval Research Laboratory; and Mark Schultz, of Sherwin-Williams Protective and Marine Coatings.
Epoxy + Polyurethane Properties
Polysiloxane XLE-80 was used for the freeboard topcoat above the amphibious assault ship USS Bonhomme Richard during a recent 10-month drydock maintenance period, Sherwin-Williams reports.
The coating “combines the properties of an epoxy and a polyurethane in one coat,” providing corrosion protection, color stability and gloss retention, the manufacturer says.
The coating system reduced drydock time because it required only two coats, instead of the traditional three plus a stripe coat, Sherwin-Williams says.
The product’s durability is “at least two to three times that of silicone alkyd,” the company boasts, meaning less maintenance painting in the future.
• Low solar absorption (LSA) semi-gloss, self-priming
• Color stability and gloss retention
• High solids (80% by volume)
• Low VOC content (<240 g/L)
• HAPS free
• Corrosion and chemical resistance
In the Pink
Sherwin-Williams says the coating came under Navy consideration when the military performance specification (MIL-PRF-24635) for weather-resistant exterior coatings added new high-durability classifications (Type V), opening the door to alternative anti-corrosion coating technologies that offered longer service life, required less maintenance, and could be cleaned rather than repainted.
In addition, the polysiloxane formulation reduces the gradual “pinking” of traditional silicone alkyd low solar absorption (LSA) formulas used by the Navy to reduce heat absorption into the vessel.
In a directive issued in December 2010, NAVSEA notes the “pinking” problem and prohibits future acquisition of the older-generation “haze gray” silicone alkyd coatings for this reason.
NAVSEA “has developed far more fade/color shift resistant, high-durability, polysiloxane, haze gray, topside paints that have shown virtually no evidence of color shifting in three years of shipboard testing,” the memo said.
“The use of these new, polysiloxane, haze gray, MIL-PRF-24635, Type V, Class 2, Grade B, ‘high durability’ paints is recommended, understanding that these are two-part paints that require mixing of parts A & B before application.”
The list of Qualified Products included three coatings, including XLE-80.
More information: protective.sherwin-williams.com.