Spot Priming Rust: Converting Corrosion on Screw Heads

You have just painted your metal gate, your garage door, or your corrugated shed roof. It looks pristine. Then, the first rain comes. You look closer and see it: every single screw head, bolt, and rivet has turned orange, and ugly rust streaks are running down your fresh paintwork.

Why does the fixing rust when the panel doesn't? The protective coating on screws can often be stripped off when they are being fitted, leaving the metal unprotected. You don't need to replace hundreds of screws (which is expensive and risks leaks). You need to Spot Prime.

1. The Solution

You cannot just dab gloss paint onto a rusty screw. The rust is active. It contains moisture and oxygen. If you paint over it, it will bubble up and push the paint off within weeks. 

You will need to remove as much of the surface rust (if it is currently present) with a wire brush, and use an anti-corrosive primer to lock the rust and stop it from spreading.

2. The Preparation: The Wire Brush

Do not apply chemicals to loose flakes.

1. Scrub: Take a small brass or steel wire brush (spark plug brush size). Give the screw head a quick, aggressive twist.

2. Clean: You want to remove the flaky orange dust, but leave the hard, dark rust behind (the converter needs some rust to react with).

3. Wipe: Clean the dust away with a rag.

3. Anti-Corrosive Oxide Primer Application

Do not use a spray can. You will get black converter all over your nice clean surrounding paintwork. Treat this like detail work.

• The Tool: Buy a small painters brush, fine tip ideally.

• The Pot: Decant a tiny amount of Everest - Anti-Corrosive Oxide Primer into a container (Never dip the brush into the main bottle - you will contaminate the clean liquid with rust particles).

• The Technique: Pick up some Anti-Corrosive primer on your brush and touch the brush to the screw head. Just dabbing will work.

• Let capillary action do the work. The liquid will suck itself into the threads and under the washer.

• Be careful not to let it run down the panel.

5. The Topcoat: Encapsulation

While Everest - Anti-Corrosive Oxide Primer is an excellent primer, it is not a UV-stable topcoat. If left exposed to the elements, it will eventually degrade and lose its effectiveness. To ensure a long-lasting, professional finish, you must seal the treated screw heads with a high-quality cladding paint that matches the rest of your roof or gate.

Everest Oxide Gloss: Anti-Corrosive Protection For the most durable results, we recommend using Everest - Oxide Gloss - Anti-Corrosive Paint. This oil-based topcoat is specifically engineered for industrial cladding and barn environments. It provides a tough, high-gloss barrier that deflects UV rays and resists moisture penetration. By spot-painting your fixings with this anti-corrosive formula, you create a seamless look while adding a secondary layer of protection that keeps the rust from returning.

The Plastic Cap Alternative If you are working on a massive corrugated metal roof, painting hundreds of individual screws can be a tedious process. In these instances, you might consider using Polytops. These are plastic caps designed to snap directly over the existing hex-head screws.

Benefit: They provide a physical seal that hides the rust and prevents water from reaching the metal entirely.

Note: You still need to apply Everest - Anti-Corrosive Oxide Primer to the metal before snapping the cap on. This ensures that any existing corrosion is neutralized and cannot spread further beneath the plastic encapsulation.

Conclusion

Rust streaks ruin the look of a property, but they are easy to fix if you are patient. Don't ignore the little orange spots. They are the weak link in your waterproofing.

• Wire brush the flake

• Encapsulate the rust with an anti-corrosive primer

• Seal it with paint or a cap

Ready to get to work? 

→ Shop our Everest - Anti-Corrosive Oxide Primer

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