Cortec Offers Alternative to Sandblasting for Rusty Surfaces

Sandblasting, water blasting and labor-intensive grinding are common methods of restoration and surface prep for rusty metal parts or structures. However, these techniques are sometimes prohibited or not preferred for a variety of reasons. To address this need, Cortec Corporation (St. Paul, Minnesota) offers an effective surface prep alternative to abrasive blasting or grinding in the form of CorrVerter Rust Converter Primer.

CorrVerter is a fast-drying, water-based, one-component primer for rusty surfaces. It contains a unique formulation of chelating agents combined with a high solids waterborne latex that reportedly has extremely low water-vapor permeability. According to the company, the combination of these materials converts surface rust into a hydrophobic passive layer, creating a specialty primer with excellent protection against re-rusting of metal surfaces.

CorrVerter can be used almost anywhere a tight layer of surface rust is present. Rather than requiring special equipment or labor-intensive abrasion to remove the corrosion, users of CorrVerter simply need to brush off loose rust before priming right over the surface. Once the surface is primed and passivated, it can be top-coated with either a water-based or solvent-based paint (urethanes, epoxies, acrylics and alkyds) for further protection and aesthetics. CorrVerter should be applied at 5.8-8.7 mils (147-221 µm) WFT (wet film thickness) in order to achieve a dry film thickness (DFT) of 3.0-5.0 mils (75-125 µm). It is said to show excellent 5B adhesion.

In addition to simplifying surface prep, CorrVerter has several other advantages. As a water-based coating, CorrVerter is considered to be a more environmentally responsible option and is also easier for workers to clean up. It also is said to have an extremely low VOC of 0.1 lbs/gallon (12 g/L). Additionally, as a single component system, it is faster and more convenient to use than primers that require the mixing of two parts together.

According to Cortec, CorrVerter has been used around the world for restoration of rusty forklift rental equipment; restoration of corrosion damaged car rims; restoration of 200 corroded electrical piers; priming of sunflower oil reservoirs where blasting was prohibited; preservation of a steel spiral staircase that would have been damaged by the force of mechanical rust removal; passivation of rusty equipment and structural surfaces in oil and gas layup projects; surface prep of rusty rebar for concrete repairs; and restoration/preservation of rusty downhole casing joint pipe exteriors.