Bilt Hamber Deox-C | Crystalline Rust Remover Concentrate
A rust remover that leaves the steel alone
Deox-C is supplied as a crystalline, 100% active powder that you dissolve in water to make a rust-removing bath. The headline claim is the one that matters: it removes corrosion products from steel without aggression to the underlying sound material. Bilt Hamber state it will not remove sound steel surrounding a corroded area, which is why it can be used on genuinely delicate items — thin sheet, fine threads, fragile castings — that an aggressive acid would eat.
The numbers
Bilt Hamber's SDS puts the working solution at pH 3.5–4.0. It is mildly acidic. It carries no CLP hazard classification at all — Section 3 of the SDS lists no hazardous ingredients, and Section 12 records it as biodegradable, with no bioaccumulation potential and negligible ecotoxicity. That is an unusual thing to be able to say about a rust remover.
We'll be straight about what we can't tell you: Bilt Hamber do not publish the active ingredient, and their SDS names none. You'll find plenty of forum confidence about what's in it. We're not going to repeat guesses as fact.
Dilution
5% is the recommended strength — 1 part Deox-C to 19 parts water. That means 1kg makes a 20 litre bath, which is Bilt Hamber's own figure, not ours. Step up to 20% (1:4) for very heavy corrosion or a longer-lived bath.
Dissolve in hot water and stir until the solution runs water-clear. Heat is the accelerator: at around 70°C the process is dramatically faster; at 10°C it crawls. Use plastic or stainless vessels only — never steel or galvanised. Lift the item and brush it periodically. Heavy corrosion can take 72 hours or more. When the bath turns dark yellow to black, it's spent.
Where not to use it
Do not immerse zinc, lead or tin, or alloys containing them. Prolonged immersion will also dull polished surfaces. And while it carries no hazard classification, it will sting cuts and abrasions, and Bilt Hamber's SDS warns that eye contact can cause lasting damage — so wear eye protection and gloves regardless of what the label doesn't say.
Finish the job
Bare, de-rusted steel flash-rusts fast. Add Atom-Mac at 2% to your rinse water to stop it, then get a coating on.
Safety Data Sheet (Australia)
Download the Bilt Hamber Deox-C SDS (PDF)