Steel parts in a shipping container face heat, humidity, and condensation over weeks or months in transit. In tropical and coastal conditions, surface rust on unprotected bare steel can develop within days. For equipment manufacturers and exporters, arriving at destination with corroded goods is a commercial problem.
The RNE Pumps test
RNE Pumps, based in South Africa, coated a batch of pumps with Corrosion Assassin in December 2024 before shipping to Miami. The shipment was opened in June 2025 — six months after coating, including sea transit time. The pumps showed zero corrosion. Other items in the same container had developed rust during the transit period.
Corrosion Assassin removed rust almost instantly, saving us hours of work.Zack Herridge · RNE Pumps
Note: Zack Herridge’s quote refers to the rust removal application on pumps returning from mining environments. The transit test is a separate application — pre-shipment protection — also carried out by RNE Pumps.
Why shipping containers are a corrosion risk
Containers experience significant temperature swings between day and night, especially at sea. This creates condensation cycles — moisture forms on cool metal surfaces, then evaporates. Bare steel in this environment oxidises.
Parts that are clean and bare after machining are particularly vulnerable. The clean metal surface has no protection against the moisture in the container air.
How pre-shipment treatment works
Treating bare steel with Corrosion Assassin before packing leaves an iron phosphate layer on the surface. This layer slows the rate of oxidation during storage and transit. It is not a full coating — it is a treatment that buys time and protects the surface condition of the part.
When the shipment arrives, the treated surfaces are clean and in the same condition as when they were packed. If painting or further processing is required on arrival, the phosphate layer improves adhesion for the topcoat.
Application before packing
- Ensure parts are clean and free from oil and contamination.
- Apply Corrosion Assassin to all bare steel surfaces — brush or spray application.
- Allow dwell time — the phosphoric acid reacts with any surface oxidation.
- Wipe or rinse off residue and allow to dry.
- Pack for shipping — the treated surface is stable and protected.
Keep reading: what rusted, returned parts cost versus preventing it, or see the Corrosion Assassin rust remover.
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