Rust converter is a paint-on treatment that turns surface rust (iron oxide) into iron phosphate, and our Septone Rust Converter 500 ml needs at least 30 minutes to dry completely on a heavily rusted area before you prime. Brush it on, let it dry, then prime as soon as possible: its protection is only temporary.
That's the short answer. The steps, the safety gear and what the maker doesn't publish are below.
| Septone Rust Converter | What the maker's documents give |
|---|---|
| What it is | A concentrated rust converter based on phosphoric acid (470 g/L on the 500 ml label) |
| What it does | Converts surface rust (iron oxide) into iron phosphate, a base for primer and top coat |
| How to apply | By brush |
| Drying before primer | Let it dry completely: 30 minutes minimum on a heavily rusted area |
| After it dries | Primer coats as soon as possible; it is temporary protection, not a coating that stops rust coming back |
| Suits | Rusted galvanised roofs or surfaces, ornamental ironwork, fencing, structural steel, automotive panels, rusted nuts and bolts, hand tools |
| Not given online | Coverage per litre, a temperature range, a maximum time before priming |
| Hazards | Signal word Danger: causes serious eye damage, may cause an allergic skin reaction, harmful if swallowed, may be corrosive to metals; Schedule 6 poison |
| Transport class | Dangerous goods Class 8, UN 1805, packing group III |
Source: Septone's product page, FAQs, safety data sheet and 500 ml front label (see Sources), read 8 October 2026.
Rust converter is a pre-paint step, not a finish
On rusty steel, rust converter changes the surface rust rather than taking it off: it turns iron oxide into iron phosphate, and that layer is the base for the coats that do the protecting. It's a pre-painting treatment, and it gives only temporary protection. It shouldn't be treated as a coating that will stop the metal rusting again. So the job isn't finished until the primer and top coat are on.
That's why the timing question matters both ways. Prime too soon and the converter hasn't dried; leave it too long and you're relying on protection the maker calls temporary. The answer is to let it dry completely (30 minutes minimum on a heavily rusted area), then apply primer coats as soon as possible.
That 30 minutes is the only drying or painting time in Septone's product page, FAQs and safety data sheet for this product. They give no coverage rate, no temperature range and no latest time to prime, so we don't give one either. Read the directions on the bottle before you start, and don't borrow figures from a different product: rust converters aren't all the same chemistry.
How to use Septone Rust Converter
- Read the label first. The front of the bottle says to read the safety directions before opening or using.
- Gear up and ventilate. Wear gloves, a face shield, overalls and safety shoes. Gloves of nitrile rubber or PVC should suit intermittent contact. Work only in a well-ventilated area, avoid breathing the mist or vapour, and don't eat, drink or smoke while you use it.
- Brush it onto the rusted area. Apply it by brush.
- Let it dry completely. Allow at least 30 minutes on a heavily rusted area.
- Prime as soon as possible, then top coat. The converter prepares the metal for priming and top coating; it isn't the finish.
- Clean up. Wipe up small spills with a clean rag or paper towels, seal them in a labelled container for disposal, and keep it out of drains and waterways. Wash your hands, face and any exposed skin thoroughly afterwards, and wash contaminated clothing before you wear it again.
- Store it safely. Keep it in its original packaging, standing upright with the cap closed, in a cool, dry, well-ventilated place out of direct sunlight, away from food and out of reach of children.
Is rust converter dangerous? What the safety data sheet says
Yes, treat it with care. The safety data sheet classes Septone Rust Converter as hazardous, with the signal word Danger. It contains phosphoric acid (30 to 60%), it's a Schedule 6 poison, and it's a Class 8 corrosive dangerous good for transport. The biggest risk is to your eyes: it causes serious eye damage and can cause corneal burns. It can also cause an allergic skin reaction, it's harmful if swallowed, and it may be corrosive to metals.
First aid, from the safety data sheet:
- In the eyes: rinse straight away with plenty of water for 15 minutes, holding the eyelids open (take out contact lenses if it's easy to do), and get medical help urgently.
- On the skin: take off contaminated clothing and flush the skin with running water. Get medical help if swelling, redness, blistering or irritation appears; the effects may be delayed.
- Breathed in: move to fresh air and rest; get medical advice if the effects persist.
- Swallowed: rinse the mouth with water and don't induce vomiting. Give a glass of water, but never give anything by mouth to someone who is unconscious. Call the Poisons Information Centre (131 126 in Australia) or a doctor straight away.
Buying rust converter from Bearings Express
- Pick the Septone Rust Converter 500 ml for surface rust on steel and iron before you paint: fences, ironwork, roofs, panels, nuts and bolts, and hand tools.
It's classed as a dangerous good, so we send it by road only, double-packed, and we can't send it to Tasmania. It's the only rust converter we stock. Our other accessories are in Accessories.
Questions people also ask
Can I spray rust converter?
Septone's directions describe brushing it on, and its online documents give no spray directions. The safety data sheet also says to avoid breathing its mist or spray.
Can I use rust converter on galvanised iron?
Yes, on rust. Septone lists rusted galvanised roofs and surfaces among its uses.
Is Septone Rust Converter the same as Septone Rust Prime?
No. Rust Converter turns rust into iron phosphate before you prime. Rust Prime is a separate water-based Septone product that turns rust into an inert black compound instead of iron phosphate, and it isn't suited as an automotive primer. We stock Rust Converter only.
What's the best rust converter in Australia?
We stock one, so we won't rank brands. Whichever you look at, check three things on its own label and safety data sheet: what rust and surfaces it's for, how long it must dry before primer, and what safety gear it needs.
Does rust converter remove rust stains?
Septone lists it as suitable for removing rust stains from porcelain, marble and terrazzo.
Related reading
Sources
- Septone (ITW Polymers & Fluids), "Septone Rust Converter" product page, https://www.septone.com.au/product/rust-converter/, read 8 October 2026.
- Septone, FAQs, section "Rust Prime, Rust Convertor, Rust Shield & Rust Proof", https://www.septone.com.au/faqs/, read 8 October 2026.
- ITW Polymers & Fluids, Septone Rust Converter Safety Data Sheet, reference 40176, version 2.0, issued 8 October 2025 (linked from Septone's product page), https://go.lupinsys.com/itw/harms/pm/bb5c4ea06705fd47c8d5865ef9e980ba-published/attachment/sds-aus.pdf, read 8 October 2026.
- Septone, product photo of the 500 ml bottle (AUR500) showing the front label, https://www.septone.com.au/wp-content/uploads/AUR500_1200x1200.jpg, read 8 October 2026.
Checked against Septone's product page, FAQs and safety data sheet, and our product listing, on 8 October 2026.
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