How to Protect Mould Tools from Rust and Corrosion

Mould tools used in injection moulding or die casting—particularly those made from reactive metals—are vulnerable to rust and corrosion. This is often due to exposure to moisture, condensation, and corrosive gases released during the moulding process. In this blog, we outline how to effectively protect your mould tools from these damaging elements, including the use of Mould Protection Spray.

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Why Do Mould Tools Rust and Corrode?

Mould tools are typically manufactured from steel, including tool steels such as P20, H13, or stainless grades. Regular steels contain iron, which readily reacts with oxygen and moisture to form rust. Even stainless steels can corrode if scratched or exposed to aggressive chemicals over time.

The injection moulding process involves repeated heating and cooling cycles. As the mould cools, condensation can form on the tool surface—particularly in humid environments. This moisture, in contact with hot metal, accelerates oxidation. Furthermore, during machine shutdowns or maintenance periods, temperature variations often cause water vapour to condense inside mould cavities.

The materials injected into mould tools—such as plastics, rubbers, or metal powders—can also emit corrosive chemicals or trap moisture, further increasing the risk of rusting.

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Mould Tool Maintenance

Proper maintenance is key to preventing corrosion. Moulds should be thoroughly cleaned, dried, and treated with anti-rust products before being stored. The frequency of maintenance depends on several factors, including:

• The intensity of tool usage

• The types of materials processed

• The criticality of product quality

Neglecting maintenance accelerates wear and corrosion, potentially leading to costly repairs or replacements.

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Moleroda Mould Protection Spray

At Moleroda, we’ve developed a high-performance mould protection spray designed to guard against rust and moisture damage. Our sprays are specifically formulated for use in the plastics and rubber industries and are suitable for both short-term and long-term storage.

Available in clear and coloured options, our sprays provide reliable coverage and peace of mind.

Why Use a Coloured Mould Protection Spray?

Coloured sprays offer a significant advantage: they make it immediately visible where protection has been applied. This is particularly important when working with moulds that feature:

• Complex geometries

• Deep cavities

• Sharp corners

• Hidden surfaces

Using a coloured spray ensures complete coverage and helps identify missed spots instantly—reducing the risk of rust forming in unprotected areas.

Coloured sprays also assist with routine inspections. Technicians can easily confirm whether the protective coating is intact or if reapplication is necessary due to handling or wear.

Additionally, colour coding can be used to indicate tool status. For instance:

• Blue might signify a tool freshly coated and ready for storage

• Red could denote a tool awaiting inspection

This system improves workshop organisation and enhances communication among maintenance teams.

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How to Use Moleroda Mould Protection Spray

1. Shake the can thoroughly before use

2. Spray onto the clean, dry tool surface from a distance of 12–14 inches (30–35 cm)

3. Maintain consistent pressure on the valve during application

4. Do not spray onto hot tools or directly onto plastic or rubber components

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Protect your investment. With proper maintenance and the right protective products, you can extend the life of your mould tools and reduce downtime due to corrosion-related failures.