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Metal fences often get rusty over time, especially in harsh winter climates or seaside environments. Instead of repeatedly sandblasting the rust off, workers can opt for the Cortec^® alternative of passivating the rust with CorrVerter^® Rust Converter Primer.

Sandblasting Challenges

While sandblasting effectively removes rust, the process requires special equipment, can be a worker hazard, and is not allowed in some environments. In addition, a freshly blasted metal surface is a magnet for flash rust, potentially starting a vicious cycle of sandblasting over and over again if the metal fence is not properly treated or painted quickly enough.

CorrVerter^® Rust Converter

If sandblasting is not preferred, workers can instead grab a wire brush and a pot of CorrVerter^® Rust Converter Primer to get started reclaiming a rusty fence. CorrVerter^® is a water-based primer with a low VOC of 0.1 lbs/gallon (12 g/L). It combines chelating agents with a high solids waterborne latex that has extremely low water vapor permeability. This chemistry converts surface rust to a hydrophobic passive layer and deters re-rusting. CorrVerter^® changes from white to dark brown/black as it cures and can be top-coated with both waterbased and solvent-based paints.

How to Paint a Rusty Fence

Painters who opt to use CorrVerter^® on their rusty fence should first brush off loose rust, rinse the fence and allow it to dry, then apply a 3.0-5.0 mil (75-125 µm) DFT (dry film thickness) coat directly over the remaining tight rust. If desired, a second coating of CorrVerter^® can be applied after 20 minutes. For best results, this should be left to dry 24-72 hours and then top-coated with either a water-based or solvent-based permanent coating, such as EcoShield^® VpCI^®-386 (water-based) or VpCI^®-384 (2K solvent-based urethane). Both the primer and coatings can be applied by spray or brush

Sandblasting – Not the Only Option

If your facility has a rusty fence that needs to be fixed up, remember that sandblasting is not the only option. With CorrVerter^®, facilities can paint directly over the rusty surface without using special equipment or worrying about blasting hazards. Contact Cortec^® to learn about painting your rusty fence.

Keywords: sandblasting rusty fence, how to paint a rusty fence, how to passivate rust, rust converter, rust primer, flash rust on metal, alternatives to sandblasting, Cortec, Cortec Coatings, maintenance tips

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Piping is everywhere in process industries such as chemical and petroleum production. Furthermore, flange faces on the end of almost every pipe segment form a critical connection for pressure containment. Any deterioration of these surfaces could diminish the integrity of that connection, making preservation imperative for safety and performance concerns. Removable coatings are a great way to ensure faster installation and less downtime by keeping corrosion away from the flange face.

Removable Coatings for Flanges

Cortec® recommends two removable coatings for flange face protection. VpCI®-391 is a water-based temporary coating with low VOC (0.4 lbs/gal [48 g/L]). It leaves a clear non-tacky film that is virtually unnoticeable and can be easily removed with alkaline cleaners such as Cortec’s VpCI®-41x Series (which offers flash rust protection) before the pipe spool is installed. VpCI®-391 provides protection in harsh, outdoor, unsheltered applications and has excellent UV resistance. Since the coating leaves a dry film, it is ideal for transit applications where pipes and flanges may be repeatedly handled. For the most extreme conditions, VpCI®-368 offers even heavier duty protection. This fast-drying solvent-based coating leaves a slightly brown waxy finish and should be removed prior to flange installation using an alkaline cleaner from the VpCI®-41x Series. 

Removable Coating Advantages

As previously suggested, the main benefit of removable flange coatings is to avoid the ramifications of corrosion. Eric Uutala (Cortec® Technical Sales and Product Manager), who has extensive field experience with oil and gas industry preservation, explained the alternative: “If a raised face is damaged, either from corrosion or mechanical impact, it can cause significant delays in construction in startup activities. In the case of gramophone raised faces, the re-surfacing process can be very time consuming which could lead to further downtime (and money loss).” By taking the removable coating route, the protective mechanism conforms directly to the surface of the metal, not requiring an additional covering (e.g., plastic film) except what is needed for standard mechanical protection. In the case of VpCI®-391, there is minimal change to appearance—a plus for manufacturers concerned about aesthetics—and the coating is especially easy to remove for faster startup of the system.

Best Practices for Coating Flange Faces

Uutala reminds workers that flange preservation can be done at any point in the pipe life cycle—at the manufacturing plant, in the storage yard, or at the final site of operation. He outlines the flange coating process as follows:

• Make sure the flange face is clean and free of rust, dirt, coatings, and any other contaminants.
• Apply either VpCI®-368 (for brown, waxy film) or VpCI®-391 (for clear, dry film) by brush.
• Allow to dry for 1-2 hours (or more) before covering with rigid flange cover or other approved mechanical protection (avoid wood covers because they absorb moisture).

The Bottom Line

Ultimately, the condition of the flange face directly affects the condition of the system and is at risk at any point up to installation. Taking preventative measures to protect vulnerable flange faces from corrosion and mechanical damage during shipping and storage can go a long way toward preserving flange faces in their original state. A little time spent cleaning the flange and applying a coating now could translate into many hours and dollars saved later by avoiding resurfacing delays and minimizing system downtime. Contact Cortec® today to learn more about removable coatings for flange faces:
https://www.corteccoatings.com/contact-us-2/

Keywords: temporary coatings for flanges, less downtime, faster installation, process industries, corrosion on flange face, removable coatings for flange protection, removable coating advantages, best practices for coating flange faces, Cortec, VpCI, protect flange faces from corrosion

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