That very light, brown rust / discolouration

Does anyone know a way to remove that very light, brown surface discolouration you tend to get on machine tools? You know the kind im talking about, it looks like rust (probably is) but its perfectly smooth to the touch and steel wool doesn't usually work on it. Sandpaper does work but im hoping for a non abrasive solution?

Anyone?

Hi there.

If I have something that is ‘rusty / discoloured’ that I want to clean up, but not remove metal in the process. I use a worn out ‘green scouring cloth’ (the type used to remove burnt on food from cookware) lubricated with oil and rub the affected area. If it is a stubborn stain I may use a new scourer, but still lubricate it with oil.

I frequently remove the ‘dirty oil’ and re-oil as I feel the removed rust is probably quite abrasive anyway. It seems to work but does require some ‘elbow grease’.

Just one suggestion - I am sure other methods will be along in a few minutes.

Best regards. Alan.

Steel wool or worn emery cloth with oil

Edited By roy entwistle on 25/01/2021 15:05:12

I can recommend Frost Rust Remover. I had a problem the other year when I silver soldered a boiler in the workshop and all steel items developed a brown film on the upper surfaces. I tried some of the frost rust remover and it quickly removed the film but it needed a light polish to make it bright again.

It then needs a wash in water followed immediately by dewatering fluid such as WD40.

I have no connection other than as a very satisfied customer.

Brian

Edited By Brian H on 25/01/2021 15:09:42

It can be oxidised oil. If it is, a strongly alkaline cleaner may remove it.

We used something like Metal Brite at my last employment for cleaning & brightening machined surfaces on rebuilt machine tools. I'm not certain it was this exact product, but recall the one we used contained phosphoric acid which the SDS for Metal Brite shows too.

It was very effective - planed cast iron surfaces came up like freshly machined. The only references I can find are for 25 litre drums, though.

Otherwise, on a slightly abrasive note, brick red "extra fine" Scotchbrite pads used with WD 40 (or similar) work well with minimal surface scratching. For stubborn coolant & tramp oil residues, I use DEB Janitol Rapide water based caustic cleaner diluted about 4:1 with water. Apply with a trigger action spay bottle, leave to stand for a few minutes & wipe off with paper towels. Repeat as required on stubborn stains. Being caustic, it takes the shine off painted surfaces & should be used with eye protection & waterproof gloves.

Nigel B.

A solvent based degreaser followed by oiled steel wool would be all I would use, no abrasives.

Scotchbrite or equivalent green scourer - available in rolls from B&Q etc. - with WD 40.

In many or most cases, unless the rust really has a hold, you can get back to a bright finish with no detectable metal removal. Happens most winters to the chuck, milling vice, cross- and compound slide top surfaces on my Warco WM250V, but after half-an-hour or so's work you'd never think it'd been there.

I think I'd have to live another 2- or 300 years for it to cause any wear to worry about.

Edited By Mick B1 on 25/01/2021 17:16:47

Not directly what you have asked about but related, I find Lanolin a very effective rust inhibitor during the winter months. IIRC a jar costs about £6 on the Bay and it will last you a lifetime. It is better for tools not in regular use as it is a bit greasy, but a very thin coat is all it takes. It is easily removed and as sold has a pleasant smell.

Search for :Dax 100% PURE LANOLIN Super Hair Conditioner

Removing the brown finish will restart the battle to keep the bright finish. The brown patina tends to be stable whereas a bright finish will immediately want to return to the brown one.

Mike

In the sporting gun world (UK version) a gun which is nicely browned is regarded as 'just right'. No, not a kalashnikov, nothing a Trump wally might flaunt, but a nice black-powder percussion cap twelve bore, of course.

Cheers, Tim

Some interesting food for thought. Might have to give the rust remover a go. Some of my tooling has a nice engine turned type finish, obviously abrasives would spoil the finish.

Lanolin is used on the Lockheed Hercules C130J propellor hubs. The hubs are sulphuric anodised, but not subsequently painted, but coated in lanolin. Paint might conceal underlying deterioration, and the lanolin gives protection for the hub under the cowling, but can be easily be washed off with solvents for close inspection.

Breva's post reminded me of this.

Edited By old mart on 25/01/2021 20:13:01

Lanolin - I was once given a bottle of the stuff and IIRC it was mixed with white spirit. It was used by RR to preserve some parts of an RR jet engine (cant remember what) . I used to use it on my motor bike spokes & rims during winter months. It was brilliant!

Matt

Those Trump wallies are more likely to carry AR15's, a rifle that uses an aluminium alloy receiver and hand guard, most likely modern protection methods on the barrel like cerakote etc, unlikely to have any corrosion issues, this being an engineering forum, might as well make your snide remarks accurate and relevant.

Lanolin is now available in spray cans by the makers of WD-40 at the hardware store.

Lanolin was always used by the MoD to preserve weapons. MANY years ago n the Air Cadets we were supplied with some deactivated Lee Enfield Mk3s which were smothered in lanolin. It took a lot of removing.

Brian

Lanolin dissolved in white-spirits is an old but effective preservative for wire-rope, especially when such ropes had sisal cores. The rope is soaked in the solution then hung up to drain and dry. Worth considering for trailer-winches, and for winding-ropes on miniature traction-engines & ploughing-engines.

As far as I know lanolin is not only tenacious and long-lasting, but also doesn't carry the skin-health risks inherent with mineral oils.

'

I tried to investigate gun-blue for protecting the bare steel parts on the tool-&-cutter grinder I am building. My security software blocked my attempts, and so far I have no reply from a major country-sports stockist that lists the stuff but not the weapons, making me wonder if the system stopped its transmission!

Yes I did try "ours" first but it looks as if only Chronos stocks metal-blacking, and then warns it gives no real protection against rusting.

I have found that Inox MX3 is quite a useful lubricant and metal protector for workshop use. It is lanolin based. More info here Inox and Lanox engineering uses

* danny *