Rust Preventive Oils: Types, Selection and Applications

Rust preventive oil is a protective coating applied to metal surfaces to keep moisture, oxygen and salts away from the metal. It leaves a thin film — oily, waxy or dry-to-touch — that slows or prevents corrosion during processing, storage and transport.

It depends on the product, film thickness, packaging and environment. KG-3 has a reference period of one year unpackaged and 3–5 years with plastic-bag packing; long-term grade KG-8 is rated for 3–5 years on precision parts. Real protection time is always set by storage conditions.

Start with four facts: the metal (steel, cast iron, electrical steel, plated parts…), the required protection period, the environment (indoor, humid, marine, export shipping) and how you will apply it (dip, spray or brush). Then match a grade — for example KG-2B for cast iron or KG-8 for multi-year storage — and confirm with a short trial.

Rust preventive oils are oil- or solvent-based and leave a protective film on the part. Water-based rust inhibitors are used in water-based fluids such as cleaning baths, coolants and rinse stages to give short-term, in-process protection. Many plants use both: an inhibitor in process, a rust preventive oil for storage and shipping.

Yes. Solvent-based fast-drying films can be removed with solvent cleaners, and MOERY KG-3 film is easily removed in alkaline cleaning solutions. Confirm the cleaning method before a part goes to painting, plating or welding.

Yes, when the grade and packing match the route. Sea freight exposes parts to condensation and salt-laden air, so use a long-term grade such as KG-8 or KG-9 and add a sealed plastic bag or VCI packaging where appropriate.

Cast-iron engine parts such as cylinder heads and liners suit KG-2B / KG-3B; plated or phosphated fasteners suit KG-2C / KG-3C; sintered parts suit KG-4A / KG-4B. See the Automotive application page for a full selection table.

Remove machining residue, salts and fingerprints, then rinse and dry thoroughly. Check blind holes and seams for trapped water. Confirm that the chosen grade is compatible with the metal and any surface treatment; trial the complete cleaning and application process on representative parts.

Allow the film to form before packaging. Choose clean, dry packaging suited to the storage period and route, seal it where appropriate, and protect parts from condensation, moisture and physical damage. Inspect samples periodically and adjust the process if the film or packaging is damaged.

Yes. MOERY develops customized formulations around a customer’s metal, process and protection period. Send us the application details and sample requirements and our engineers will propose a formulation and a test plan.