The Hidden Cost of Rust for South African Manufacturers

Rust appears on the maintenance line of a P&L. The costs it generates do not always appear on the same line.

For manufacturers, fabricators, and operations managers, corrosion creates losses in four places — most of which are not captured as a corrosion cost in the accounts.

1. Parts written off in stores

Finished or semi-finished steel parts held in storage oxidise. In humid storage conditions, surface rust can develop on bare steel within hours. Parts that arrive at assembly with surface rust face two outcomes: rework before use, or rejection.

Neither outcome shows up as a corrosion cost. It shows up as rework labour, downtime, or a write-off.

2. Rework before shipment

Parts destined for export or delivery that develop rust in transit or in finished goods storage require treatment before they can be shipped or accepted by the customer. That treatment costs labour time and product. If the part cannot be recovered, it is scrapped.

3. Coating failures and call-backs

When rust under a coating causes delamination or bleed-through after delivery, the cost is a customer call-back, a warranty claim, or a reputational consequence. The root cause is inadequate surface preparation before painting — typically rust left on the surface before the topcoat was applied.

4. Labour time on surface preparation

Mechanical rust removal — grinding, wire brushing, sanding — is labour-intensive. On high volumes of rusted parts, it consumes significant workshop hours. Those hours have a direct cost that is rarely attributed to corrosion in the accounts. It shows up as labour.

Where chemical treatment changes the calculation

Treating steel surfaces with a phosphoric acid-based product before storage, between process stages, or before shipment addresses the problem before it becomes a cost. The iron phosphate layer left by the treatment slows further oxidation without requiring a full coating.

For manufacturers: parts protected between production stages arrive at assembly without surface rust. Rework is reduced. Coating adhesion improves because the surface is already passivated.

For exporters: parts protected before shipping arrive at destination without transit corrosion. Customer complaints and warranty costs are reduced.

Keep reading: what rust really costs once you count labour and rejects, or see the Corrosion Assassin rust remover.