Moulds and dies rust in storage when bare steel meets humidity, condensation or salty air with no protective film. The fix is to clean the tool and apply a thin anti-corrosion coating before it goes on the shelf. Micron 1201 Mould Saver is a temporary anti-corrosive wax coating whose page says it is for preventing corrosion of stored metal parts such as moulds, dies and spares. If the mould still has old release or grease on it, clean it first with Micron 1220 Mould Cleaner.
Why it happens
Tool steel rusts fast once it is idle:
- Humidity, condensation or salinity in storage. Monsoon humidity, temperature swings and coastal air all put moisture on the steel.
- No protective film. A mould put away straight off the machine has no barrier between steel and air.
- Water leaks from cooling lines. Residual water in channels or a leaking fitting wets the cavity.
You will see orange rust spots on the cavity or core, pitting on polished surfaces after a shutdown, or rust after transport.
How to fix it
- Mould is clean: apply Micron 1201 Mould Saver. Its page describes a thin, dry, colourless wax film that protects against corrosion when metal is exposed to humidity, moisture, salinity and industrial fumes, and says it is compatible with lubricants, plastics and rubbers.
- Mould still has old release or grease on it: clean it first with Micron 1220 Mould Cleaner. The 1220 page lists pre-treatment before applying anti-rust or protective sprays. Let it evaporate fully, then apply 1201.
Before storage, also blow out and dry the cooling channels so trapped water does not rust the tool from the inside.
The 1201 page does not give step-by-step directions. Follow the instructions on the can and the TDS: a thin, even film over all exposed steel, including cavities, cores and parting surfaces.
When the mould comes back into service, the page says coated parts can be reused "without much preparation". Check with Micron whether to wipe the cavity before the first shot, especially for parts with a critical surface finish.
What to avoid
- Do not rely on release agents for storage protection. They are designed for moulding, not for keeping moisture off steel for weeks.
- Do not coat over existing rust and expect it to disappear. The coating prevents further rust; it does not reverse pitting.
- 1220 is a solvent cleaner. Treat it as flammable until the SDS says otherwise, use ventilation, and keep it away from sparks and flames.
- Do not store moulds with water left in the cooling lines.
When to ask an expert
Hand the tool to your toolroom if:
- there is deep rust or pitting on a polished cavity, which needs repolishing;
- rust appears even on coated moulds, which may point to a storage problem such as water ingress;
- the mould is going for long-term storage or export and you need a packing specification.
FAQ
Do I have to remove Mould Saver before moulding?
The page says coated parts can be reused without much preparation. Ask Micron whether to wipe the cavity before the first shot, particularly for clear or high-gloss parts.
Will it damage plastic or rubber parts of the mould?
The page says it does not harm rubber or plastic and is fully compatible with lubricants, plastics and rubbers.
What do the green and white variants mean?
Micron's page does not explain the colour variants. Ask Micron before ordering.
Can I use it on spare dies and machined parts too?
Yes. The page says it is for corrosion prevention of stored metal parts like moulds, dies and spares of every type of metal.
See the product: Micron 1201 Mould Saver. Related: 1220 Mould Cleaner. More moulding fixes: moulding hub.