Just because one Cortec® product is a great rust preventative (RP) does not mean that it is the best choice for every application. In fact, Cortec® offers a variety of rust preventatives with specific characteristics that make some Cortec® RPs ideal for one application and other Cortec® RPs ideal for another. Viewing these flagship RPs through the accompanying selection grids can help users decide which one they prefer for a specific situation.
Storage or Shipping Environment
The most important factor in making your decision is determining the level of protection needed. Metal parts that sit outdoors need more robust protection than those that experience only slight humidity changes indoors. Metals stored in sheltered outdoor conditions need more protection than those indoors but can take advantage of robust RPs that could otherwise be washed off in the rain.
The product carrier is another important characteristic that factors into the choice of an RP. Some users want a more sustainable, worker-friendly product that is water-based or biobased, while other companies have specs that have been around for decades and still call for solvent-based RPs.
The film type can affect handling and appearance of the protected parts. Thin, dry RPs are very inconspicuous and great for tight tolerances. Oily RPs can be good for rotating components. Thick RPs may be better where heavy-duty protection is needed.
Those responsible for choosing an RP should also consider what kind of cleaning scenario end users want to see. If power washing is okay, a thicker RP can be used. Other RPs only require light washing or no removal at all.
Next time you choose an RP, be sure to look at your options through the grids at left for the most satisfactory experience. Need more help or other options? Contact Cortec® today to discuss your specific rust preventative
Keywords: how to choose best rust preventative, Cortec, rust preventative selection guide, indoor corrosion protection, outdoor storage protection, biobased rust preventatives, heavy-duty rust preventatives, corrosion protection for tight spaces, rust preventative removal, sustainable rust preventatives
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Workers often paint metal not only to make it look nice but also to protect it from oxygen, moisture, and salts that can cause it to rust or corrode. Unfortunately, paint jobs that do not get off to the right start are little better than having no protective coating at all. To avoid wasted metal painting efforts, Cortec® stresses the importance of good surface prep and coatings selection according to the following guidelines.
Good Surface Prep for Painting Metals
Good surface prep is critical to adhesion. Paint will not adhere well to surfaces that are rusty or dirty, and if the paint peels, protection will be lost. Fortunately, there are a variety of ways to remove rust: sandblasting, grinding, blasting, or using a Cortec® rust remover such as VpCI®-423 (a USDA Certified Biobased Product that clings to vertical surfaces). Once the rust is removed, the surface should be rinsed to remove any remaining dirt, debris, or corrosion products. Power-washing the surface with an alkaline cleaner from the VpCI®-41x series further helps with flash rust prevention on freshly exposed metal surfaces and neutralizes those that have been cleaned with acids. If no water has pooled, the surface can typically be painted over without further rinsing.
In many cases, it makes more sense to passivate a rusty surface with a good coat of CorrVerter® Rust Converter Primer than to sandblast or use another method of rust removal. This is done by removing loose rust with a wire brush and then applying CorrVerte® directly over any remaining tight rust. A special combination of chelating agents and a high solids waterborne latex with extremely low water vapor permeability converts the surface rust into a hydrophobic passive layer and resists re-rusting. CorrVerter® should be allowed to dry for at least 12 hours before a topcoat is applied. It can be painted over with either a water-based or solvent-based coating.
Tips to Choose the Right Coatings for Metal
In addition to good surface prep, choosing the right coating system (e.g., primer and topcoat) can mean the difference between achieving long-term protection or premature failure. Several important considerations should be made in the process.
- Consider company specifications. Some large equipment manufacturers have specific requirements on how many hours their coatings must last in salt spray or humidity testing, or how much the color can fade over time. If the paint does not meet these requirements, it may not provide the appropriate level of protection.
- Consider the surrounding environment. For example, a metal part stored inside a warehouse may be protected indefinitely with one coat of a water-based, 1K Cortec® Coating. On the other hand, structural steel exposed to extremely aggressive coastal conditions with high humidity and blowing sand (e.g., northern Brazil) may need a three-coat system with two coats of primer and a 2K, high-UV resistant 2K topcoat such as VpCI®-384 in order to withstand the harsh environment.
- Consider the application requirements. While 2K coatings typically offer a durability advantage, they require extra labor and also have a limited pot-life before they must be thrown away. Even worse, it is easier to make application errors when using a two-part system. If workers mix the wrong amounts or completely forget to add Part B to Part A, the coating will not function properly and may need to be removed and replaced. The project owner should therefore decide whether it makes more sense to go for 2K durability advantages or the convenience and simplicity of a 1K system.
Choose Good, Better, or Best
Since so many different factors (not to mention budgets) figure into coatings selection, Cortec® is adept at recommending “good, better, and best” Cortec® Coating system options. This allows users to choose the paints that make the most sense for their specific project needs and preferences. Some popular 1K and 2K Cortec® Coatings that frequently come up in recommendations include the following:
Cortec® experts are here to help, so do not hesitate to contact us with your surface prep and coating selection questions for best results!
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