POR-15 Rust Preventive Coating
Steel surfaces that have rusted or that are vulnerable to rust must receive treatment to prevent or remediate the problem. PennCoat has had excellent results with the rust-preventative coating POR-15, which we use as a primer on new steel or on rusted steel that has first been prepared. Unlike the so-called chemical rust inhibitors — which tend to lose effectiveness over time — POR-15 works by forming a tough, hard layer that physically protects metal from water. Exposure to water increases the strength of coating, due to the product’s unique chemistry.
POR-15’s proprietary formula of solvents and resins includes:
- Polymers of ethylene oxide, propanol and isocyanic acid
- Aluminum/titanium oxide, depending on color
- Methylene bisphenyl isocyanate
The resulting product features advanced polyurethane technology. Upon application, it produces a cross-linked, non-porous film impervious to water, salt, chemicals and the contaminants that can corrode steel. The structure of the coating causes it to lock onto surfaces through multi-finger-like adhesion that cures to a permanent bond and resists chipping/peeling. The product has 74 percent solids and a viscosity of 250 to 500 cps, which means that one gallon will cover 384 square feet to a depth of 3 mils, although a 1-2 mil application is recommended.
POR-15 resists impacts in excess of 16 ft.-lbs. Its flexural strength exceeds 5,200 psi, its compressive strength is greater than 12,500 psi, and its tensile strength exceeds 3,200 psi. The bond strength is so strong that concrete will fail before a coating of POS-15 will. The highly elastic cured surface is extremely resistant to bacteria, fungus, salt, water, electrical static and heat.
Because POR-15 is moisture-cured, it actually dries faster in humid conditions, in as little as two hours. This makes the product a convenient primer. Five colors are available:
- Gloss black
- Semi-gloss black
The silver formulation contains aluminum that works well on rusted steel. The product’s only real downside is that it is vulnerable to UV rays. For this reason, PennCoat applies a UV-resistant topcoat that also provides the required cosmetic properties. Depending on the condition of a steel surface, a degreaser and/or etching solution might first be applied to prep the surface for the POR-15. In cases of heavily rusted steel, abrasive blasting might be necessary before putting on any materials.