The quick answer: EN730 Inhibited Parts Washer Fluid is a water-based, non-flammable degreaser concentrate that cleans oil, grease and machining fluids from metal parts and leaves a corrosion-inhibiting coating on mild steel that protects it in indoor storage for up to 3 months. Dilute 1 part EN730 to 24 parts water and use it at ambient temperature or heated to 40°C in an ultrasonic bath, immersion tank or spray cabinet.
Why do freshly cleaned metal parts rust?
Parts leave machining, cutting and fabrication covered in cutting fluids, oils and grease. Those soils have to come off before parts can be inspected, coated, assembled or shipped.
The catch is that a thin film of oil was also acting as a temporary barrier. Once you strip it away, bare mild steel is exposed to humid air, water left on the surface from washing, and acidic contamination such as fingerprints and process residues. In damp conditions, flash rust can appear within hours.
Many workshops therefore wash parts and then apply a separate rust preventive. That means a second product, a second process step and extra time.
What is an inhibited parts washer fluid?
An inhibited parts washer fluid is a cleaner with a built-in corrosion inhibitor. It does two jobs in one wash:
- It cleans. Surfactants and alkaline builders lift and remove grease, oil, machining fluids and dirt.
- It protects. A water-soluble inhibitor leaves a thin protective coating on mild steel, which reduces the risk of rust during storage or where parts haven’t fully dried.
What makes EN730 different from a standard parts washer degreaser?
Most degreasers clean but leave metal unprotected, and most rust preventives protect but don’t clean. EN730 combines both, so mild steel parts come out of the wash clean and protected in a single operation.
- Cleans and protects in one step, with no separate rust preventive for typical indoor storage
- Highly concentrated, diluting 1 part EN730 to 24 parts water
- Water-based and non-flammable, so it suits workshops where solvent degreasers are a fire or storage concern
- Works in several washer types: ultrasonic baths, immersion tanks, spray cabinets, or by hand with a brush or cloth
- Removes uncured polyurethane residues, which makes it a natural follow-up to PU flushing agents
- No rinse needed for mild steel parts that need corrosion protection, because the inhibitor coating stays on the surface
How do you use EN730 in a parts washer?
In an immersion tank or ultrasonic bath
- Wear gloves and eye protection when handling the concentrate and mixing the wash solution.
- Dilute 1 part EN730 with 24 parts clean water in the tank or bath.
- Submerge the parts.
- Agitate by hand or run the ultrasonic cycle to loosen and lift residues.
- Remove the parts and lightly wipe away loose residue. The inhibitor coating stays on the surface.
- Store or reuse the parts. You can reuse the wash solution until it becomes heavily contaminated.
In a spray cabinet washer
- Dilute 1 part EN730 with 24 parts water and add it to the cabinet reservoir.
- Load the parts and run the wash cycle as normal.
- Remove the parts when the cycle finishes. Mild steel parts that need corrosion protection don’t need a rinse.
Tips for best results
- Use it at ambient temperature, or heated up to 40°C in a heated ultrasonic bath, cabinet or machine.
- For heavily contaminated parts, allow a longer soak before agitating.
- Don’t dilute beyond 1:24, as more dilute solutions reduce both cleaning and corrosion protection.
- Store unused EN730 in its original sealed container, somewhere cool, dry and out of direct sunlight.
How much wash solution does EN730 make?
At 1:24, only about 4% of the wash solution is EN730. EN730 comes in 25 litre containers.
| EN730 concentrate | Wash solution made (1:24) |
| 1 litre | 25 litres |
| 5 litres | 125 litres |
| 25 litres (one container) | 625 litres |
Which metals can you clean with EN730?
EN730 is suitable for steel and other metal parts, including mild steel, carbon steel, cast iron, stainless steel and aluminium. The corrosion inhibitor benefits mild steel most. EN730 is alkaline (pH 11.4 as supplied), so as with any alkaline cleaner, test it on a small area first when washing soft or sensitive metals such as aluminium, brass, copper or zinc-plated parts.
How long does the corrosion protection last?
On mild steel stored indoors, the coating protects for up to 3 months. Actual protection depends on humidity and storage conditions. Outdoor storage isn’t recommended, because rain and condensation will wash off the water-soluble coating.
Is EN730 safe to use?
EN730 is a non-flammable, water-based concentrate. Like most surfactant-based cleaners, including many washing-up liquids, it is classified under CLP for serious eye damage (H318) and carries a “Danger” signal word for that reason. Wear eye protection and gloves when handling the concentrate, follow the label, and see the safety data sheet for full handling, first aid and disposal information.
Who uses inhibited parts washer fluids?
- Machine shops and CNC machining operations, to remove cutting fluids and machining oils
- Metal fabrication and welding workshops
- Polyurethane processing and foam manufacturing, as a follow-up wash after PU flushing
- Automotive engineering and vehicle maintenance workshops
- Hydraulic servicing and component reconditioning
- Maintenance and repair operations (MRO), where cleaned parts are stored before use
- Aerospace and defence component cleaning, where rust-free storage matters
Frequently asked questions
What is EN730 used for?
EN730 is an inhibited parts washer fluid that cleans oil, grease, dirt, machining fluids and uncured polyurethane from metal parts, and leaves a corrosion-inhibiting coating on mild steel.
What is the dilution rate for EN730?
1 part EN730 to 24 parts water (1:24).
How long does EN730 protect against rust?
Up to 3 months on mild steel in indoor storage. Protection varies with conditions, and outdoor storage is not recommended.
Do I need to rinse parts after washing with EN730?
Not if the mild steel parts need corrosion protection. The inhibitor coating stays active on the surface.
What temperature can I use EN730 at?
Ambient temperature, or heated up to 40°C in an ultrasonic bath, cabinet or machine.
Can EN730 be used in ultrasonic baths and spray cabinets?
Yes. It suits ultrasonic baths, immersion tanks, spray cabinet washers and hand cleaning.
Is EN730 flammable?
No. It is a non-flammable, water-based concentrate.
How big is a container of EN730?
25 litres, which makes 625 litres of wash solution at 1:24.
Can EN730 clean up after polyurethane flushing agents?
Yes. It is a recommended final wash after EN705, EN706 GEL, EN710 and EN720.
Ready to clean and protect your metal parts?
See sizes and safety information on the EN730 Inhibited Parts Washer Fluid product page, or contact the Bio8 team for advice on your parts washing process. Bio8 Industrial Ltd is a UK manufacturer of cleaning products, shipping across the UK and EU.
