How to fix flaking rust before metal painting

This article explains how to fix flaking rust on metal painting with clear steps, tools and tips to make your metal surfaces strong and shiny again.

Flaking rust is a common problem on metal surfaces like fences, railings or outdoor furniture. It starts as small spots of corrosion where moisture and air eat away at the metal, causing paint to peel and rust to spread.

Left unchecked flaking rust weakens metal making it look old and damaged. Whether it’s a rusty gate or a weathered mailbox, fixing flaking rust is crucial to restore a smooth finish for metal painting.

Flaking rust happens when iron or steel reacts with oxygen and water, forming iron oxide (rust). Over time this rust lifts the paint and create flakes that expose more metal to corrosion.

Common causes include:

• Moisture Exposure: Rain, humidity, or standing water on metal surfaces.
• Poor Paint Application: Old or low-quality paint that doesn’t protect metal.
• Scratches or Damage: Chips in paint that let water reach the metal.
• Salt Air: Coastal areas speed up rust due to salty moisture.

Flaking rust is most common on outdoor metal like fences, railings, gates or patio furniture, but it can also affect indoor metal if moisture is present.

Fixing it involves removing the rust, prepping the surface and applying protective coatings to stop future corrosion.

Knowing how to fix flaking rust on metal painting saves money and keeps your metal looking great.

To fix flaking rust on metal painting, gather these tools and materials:

• Wire brush: For scrubbing off loose rust and paint.
• Sandpaper (80–220 grit): To smooth the surface.
• Scraping tool: For removing stubborn flakes.
• Rust converter: To neutralize remaining rust.
• Rust-inhibiting primer: To seal the metal (e.g., Rust-Oleum Rusty Metal Primer).
• Paint roller or brush: For applying primer.
• Cleaning solution: Dish soap and water or degreaser for grease.
• Rags: For wiping surfaces clean.
• Protective gear: Gloves, safety glasses, and a dust mask.
• Drop cloths: To protect surrounding areas.
• Bucket: For mixing cleaning solution.

These items cost about $50–$150, depending on the surface size (e.g., a 50-foot fence). Having the right tools makes how to fix flaking rust on metal painting faster and more effective.

Follow these steps to fix flaking rust on metal painting and restore your metal surfaces:

Check the metal for rust damage. Look for orange or brown flakes, bubbling paint, or pitted areas.

Focus on joints, seams, or low spots where water collects. For a 50-foot fence, this takes about 30 minutes.

Note heavily rusted areas that may need extra work. This step ensures you know the full scope of the flaking rust problem before starting.

Lay down drop cloths to catch rust flakes and debris. Wear gloves, safety glasses, and a dust mask to avoid inhaling rust particles.

If working outdoors, choose a dry day (60–80°F) to prevent moisture from interfering. Protecting your area keeps the process safe and clean, making how to fix flaking rust on metal painting easier.

Use a wire brush or scraping tool to scrub off loose rust and flaking paint. Work in small sections (2–3 feet at a time) to be thorough.

For stubborn spots, use 80-grit sandpaper to scrape away flakes. This step takes 1–2 hours for a 50-foot fence. Removing loose material is key to creating a smooth surface for metal painting.

Sand the metal with 120–220-grit sandpaper to smooth rough areas and remove remaining rust. Sand until the surface feels even and you see bare metal in rusted spots.

Wipe away dust with a damp rag. Sanding takes about 1 hour for a small surface. A smooth surface helps primer stick, ensuring a lasting fix for flaking rust.

Wash the metal with a solution of dish soap and water or a degreaser to remove grease, dirt, or oil. Use a rag or sponge, then rinse with clean water. Let the surface dry completely (1–2 hours).

Cleaning prevents contaminants from interfering with primer, making how to fix flaking rust on metal painting more effective.

Brush or spray a rust converter (e.g., Rust-Oleum Rust Reformer) on any remaining rust spots. This liquid turns rust into a stable, paintable surface, stopping further corrosion.

Follow the product’s instructions, usually letting it dry for 24 hours. For a 50-foot fence, this takes 30–60 minutes. Rust converter is crucial for preventing flaking rust from returning.

Apply a rust-inhibiting primer with a brush or roller in thin, even coats. Use a primer designed for rusty metal (e.g., Rust-Oleum Rusty Metal Primer).

Cover all surfaces, including edges and seams. Let the first coat dry (4–6 hours) and then apply a second coat if needed. Priming takes 1–2 hours for a small surface. Primer seals the metal, preparing it for painting and preventing future flaking rust.

Check the primed surface for missed spots or uneven areas. Sand lightly with 220-grit sandpaper if needed, then touch up with primer.

This step takes about 30 minutes. A thorough inspection ensures the metal is ready for painting, completing how to fix flaking rust on metal painting.

Dispose of rust flakes and debris in a sealed bag to prevent spreading. Clean tools with soap and water or according to product instructions.

Store primer for future touch-ups. Cleanup takes 15–30 minutes. Proper cleanup keeps your workspace tidy and tools ready for the next metal painting project.

Once you’ve fixed flaking rust, keep your metal surfaces rust-free with these tips:

• Check Regularly: Inspect metal every 6 months for early rust spots, especially after rain.
• Clean Surfaces: Wash metal with soap and water yearly to remove dirt and salt.
• Touch Up Damage: Fix scratches or chips in paint quickly with primer to seal exposed metal.
• Improve Drainage: Ensure water doesn’t pool on metal by adjusting slopes or adding drainage.
• Use Quality Coatings: Choose rust-inhibiting primers for long-lasting protection.

These habits extend the life of your metal surfaces, making how to fix flaking rust on metal painting a rare task.

Fixing flaking rust can go wrong if you rush or skip steps. Here are some mistakes to avoid:

• Skipping Rust Removal: Leaving loose rust causes new paint to flake quickly.
• Not Cleaning Grease: Oil or dirt stops primer from sticking, leading to rust.
• Using Wrong Primer: Non-rust-inhibiting primers won’t protect metal long-term.
• Painting Wet Metal: Moisture traps rust, causing flakes to return.
• Ignoring Safety Gear: Rust dust can harm eyes or lungs without protection.

Taking time to do each step right ensures a lasting fix for flaking rust on metal painting.

Fixing flaking rust on a small metal surface (e.g., a 50-foot fence) takes 2–3 days.

• Day 1: Inspect, remove rust, sand, and clean (3–4 hours).
• Day 2: Apply rust converter and let dry (1 hour + 24 hours drying).
• Day 3: Prime and inspect (2–3 hours).

Larger surfaces or heavy rust may take longer. Dry weather speeds up drying times and making how to fix flaking rust on metal painting faster.

The cost to fix flaking rust on a 50-foot fence is $50–$150:

• Wire brush, scraper, sandpaper: $10–$30
• Rust converter (1 quart): $15–$25
• Rust-inhibiting primer (1 gallon): $20–$50
• Cleaning solution, rags, drop cloths: $5–$20
• Protective gear: $10–$25

By doing it yourself you save $500–$2,000 compared to hiring pros, making how to fix flaking rust on metal painting affordable.

If rust damage is severe (e.g., holes in metal) or the surface is large (e.g., a barn roof), consider a pro.

They have sandblasters or power tools for heavy rust and can ensure safety on tall structures. For small projects, doing it yourself is cost effective and manageable with this guide on how to fix flaking rust on metal painting.

Fixing flaking rust on metal painting restores your fences, railings or furniture to a shiny, strong state.

By removing rust, sanding, cleaning and priming, you stop corrosion and create a smooth surface for painting.

With $50–$150 and 2–3 days, you can tackle flaking rust yourself. Follow these steps, avoid common mistakes and check your metal regularly to keep it rust free for years.