Fabricated and machined steel parts flash-rust while they wait for painting, welding or dispatch because bare steel meets humid air. The fix is a temporary rust-preventive film that does not get in the way of the next step. Micron 1201 Mould Saver is an anti-corrosive wax coating whose page says it is for stored metal parts such as moulds, dies and spares, that it need not be removed before welding, and that it is easily removable before painting.
Why it happens
- Humidity and condensation. Steel left in the shop overnight, especially in the monsoon, picks up moisture as temperatures drop.
- Bare steel left unprotected. Freshly machined, ground or blasted surfaces are clean and active, so they rust fast.
You will see flash rust on parts in work-in-progress, and rust on parts during transport or storage.
How to fix it
Choose by what happens to the part next:
- Parts will be welded later: Micron 1201 Mould Saver. Its page says it "need not be removed before welding".
- Part will be painted later: Micron 1201 Mould Saver. Its page says it is "easily removable before painting".
- Your welding line already uses water-based anti-spatter: Micron 2118 Water based Anti Spatter. Its page says it offers mild rust protection for temporary storage before further processing.
The 1201 page describes a thin, dry, colourless wax film that protects against corrosion when parts are exposed to humidity, moisture, salinity and industrial fumes, and says it is fully compatible with lubricants, plastics and rubbers. It has no step-by-step directions. Follow the instructions on the can and the TDS: a thin, even film on clean, dry parts.
Apply the protection as soon as practical after machining or fabrication, before rust starts. Coating over flash rust only slows it.
A few shop habits help as much as the coating:
- Keep WIP off the floor and away from doors, wash areas and cooling-water leaks.
- Do not leave water-based coolant drying on machined parts; dry them before coating.
- Handle finished surfaces with clean gloves, since sweat on bare hands leaves marks that rust.
- Plan the coating step into the route card so parts are not left bare over a weekend.
What to avoid
- Remove the wax film before painting. The page says it is easily removable but does not state the method, so check with Micron and test on a sample part through your paint pre-treatment.
- Do not coat parts that are wet or already rusty.
- Do not rely on a temporary film for long outdoor storage or sea freight without checking with Micron.
- Keep the can label and SDS to hand; this is a pressurised aerosol.
When to ask an expert
Hand off to Micron technical if:
- parts will be stored outdoors for a long time;
- you need to meet an export packing or preservation specification;
- your paint shop needs confirmation of how the film is removed in their pre-treatment.
FAQ
Is Mould Saver only for moulds?
No. The page says it is for corrosion prevention of stored metal parts like moulds, dies and spares of every type of metal.
Do I have to remove it before welding?
The page says it need not be removed before welding. Ventilate the welding area as you normally would.
How do I remove it before painting?
The page says it is easily removable before painting but does not give the method. Ask Micron, and test on a sample part through your pre-treatment.
Can I use water-based anti-spatter for rust protection?
The 2118 page says it offers mild rust protection for temporary storage. If your line already uses it, that may cover short waits. For longer storage, use a dedicated rust-preventive film.
See the product: Micron 1201 Mould Saver. Related: 2118 Water based Anti Spatter. More welding and fabrication fixes: welding hub.