Bumpy, flaking rust hardly looks conducive to a beautiful paint job.
But arustedmetal item can be preserved and revitalized with proper cleaning, priming, and painting.
Basics of Painting Rusted Metal
Can You Paint on the Rust Itself?
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Whenever possible, it is always best to sand off the rust and expose onlybare, unrusted metalfor painting.
This paint should always be laid on top of a primer designed for metal.
Will the Rust Show Through the Paint?
The Spruce / Sanja Kostic
Untreated reddish-brown rust can bleed through paint, especially lighter color paints.
Rust conversion primer turns the rust black and its polymers seal the rust against bleeding.
As long as the metal is properly primed, the rust should not show through the paint.
The Spruce / Sanja Kostic
Can You Stabilize the Rust Before Painting?
Oxygen, water, and iron are required for oxidationthe process that creates rust.
Using a rust conversion primer before painting halts oxidation.
The Spruce / Sanja Kostic
Tannins in the rust converter turn the rust black and stop the oxidation.
Polymers in the converter seal the metal against oxygen and water.
check that that all areas of the metaleven the back sideare coated.
The Spruce / Sanja Kostic
Even a small uncoated section is enough to allow oxidation to continue.
When Is an Item Too Rusted to be Painted?
Generally, items that are deeply pitted or pinholed are too rusted for painting.
The Spruce / Sanja Kostic
Often, an item might look promising at first.
Yet scraping and brushing take off layer after layer of rust, revealing no substantial metal underneath.
Safety Considerations
Painted items with rust may have been earlierpainted with lead-based paint.
The Spruce / Sanja Kostic
Homes builtbefore 1978may have lead-based paint.
Observe all safety techniques for working with lead-based paint.
Begin lightly, removing only the rust layers that come off easily.
The Spruce / Sanja Kostic
Use a putty knife or a five-in-one tool toscrape awaylarge sections of rust.
It is usually at this point that structurally unstable metal will collapse.
Frequently clean off the surface and the sandpaper.
Sand a few inches beyond the rusted area, as well.
Clean the Surface
Use the brush attachment on theshop vacuumto clean off the surface.
Use a degreaser or denatured alcohol to clean off any grease or oil.
Tip
Unless you also want toremove paint, avoid usingpaint thinner or mineral spirits.
They can soften the old paint, resulting in a rippled or wavy texture for the new paint.
Apply a thin coat and avoid drips.
Many rust converters are clear when they are first applied, then turn black.
Let the rust converter dry for at least 24 hours.
Paint the Metal
Apply the top color coat.
