Rust removal methods safe for cutting tools / precision parts?

[RainbowsParticipant @rainbows]

[RainbowsParticipant @rainbows]

Such is life I now have two mucky Sigma comparators (about 10 times as large as I thought they were) and 5 box fulls of reamers from an auction. All of them are ok but with varying amounts of dirt and rust which while individually would be easy to clean with wool but when scaled up to the over 100 items that seems less fun.

Can anyone recommend a good rust remover that won't eat the edges off the reamers? Preferably something I can dunk the reamers into a bucket of and some sort of paste I can brush onto the comparators

[David Standing 1Participant @davidstanding1]

Here y'go:

**LINK**

[Andrew TinsleyParticipant @andrewtinsley63637]

I can confirm that the Frosts rust remover works well. However it is somewhat dilute and doesn't last very long for any serious rust removal, I just wonder if the Arc Eurotrade rust remover may prove just as effective and maybe cheaper. I am going to try this next time I need some gentle rust removing.

For really bad items I still use phosphoric acid in warm dilute form. it certainly shifts the rust, but also a little good metal. but when the corrosion is that bad, I don't really mind as it is a lot cheaper than the fancy neutral rust removers.

Andrew.

[Gordon AParticipant @gordona]

I find that electrolysis works for me on tools etc. Washing soda is dirt cheap and not much electricity is used. Search for electrolysis rust removal on the web, lots of information out there on the subject.

Gordon.

[Neil WyattModerator @neilwyatt]

It's well known that I swear by evaporust (the Frost one) – main advantage is it isn't nasty, just a little sticky, so you can just pat dry and they are left with a rust-inhibiting coating, unlike many other treatments which leave the object prone to rapid rusting.

[Mark RandParticipant @markrand96270]

Phosphoric acid, boiling citric acid and Vinegar/salt solution will all remove metal (I've got a stainless steel teaspoon that stands witness to that).

Evaporust, EDTA or molasses solution work as chelating agents and generally do not remove the base metal (avoid any air/liquid boundary or you'll get corrosion at that point)

Electrolysis will not remove the base metal assuming you've got the right polarity.

I've used all these methods and tend towards electrolysis or molasses these days except for pickling of rough hot rolled steel, where I use the acids.

Bear in mind that none of the methods will restore corroded metal, so you'll be left with what ever pitting/loss of shiny surface that the corrosion caused. A bit of washing up liquid or similar in any of the solutions can help with general cleaning…

[Neil WyattModerator @neilwyatt]

Posted by Mark Rand on 29/11/2017 22:49:49:

Bear in mind that none of the methods will restore corroded metal, so you'll be left with what ever pitting/loss of shiny surface that the corrosion caused. A bit of washing up liquid or similar in any of the solutions can help with general cleaning…

But… electrolysis with convert some of the Iron III oxide to Iron II oxide (magnetite) that are hard and occupy much less space than rust 9which contains a lot of water). This means raised but attached rust patches can become dark stains that occupy more or less the same volume as the original metal, so you get less pitting at the risk of hydrogen embrittlement.

[Mark RandParticipant @markrand96270]

Trouble is that the magnetite tends to get blown off the iron by the hydrogen that's forming underneeth it (or by the cloth that the owner uses to dry the parts with). Major thing is that it won't remove any metal, which the acids certainly do. In the case of reamers, magnetite isn't all that good a cutting tool material and in the case of nice micron comarators it ain't that pretty either .

[John McNamaraParticipant @johnmcnamara74883]

Hot soapy water is always a good start it removes oil, grease, dirt and loose rust. Used on one part at a time, Followed by a kitchen sponge and bare hands applying Ajax household cleaning powder to the corroded parts, (No Scotch bright pads they contain carborundum powder, very scratchy). Its up to you to avoid rounding edges. the sponge or the hands will not provide a solid backing for the powder making it a gentle process.

After a couple of minutes check the progress by drying the part and inspecting it. if its heavily rusted then stronger methods will have to be used but often this process is enough. You may have to repeat it several times. as you work on the harder spots.

Once completed rinse in hot water then thorough drying with a cloth, do not leave any water on the part or you will get rust spots. Paper towels work well then oil the part to stop new rust forming.

It works for me.

Regards
John

[clogsParticipant @clogs]

John Mc,

bet the younger generation wouldn't know how to use the Ajax powder……..

I'm surprised it's still made…..

spose the bxxxdy accountants haven't found that 1 yet…….hahaha…..clogs

[John McNamaraParticipant @johnmcnamara74883]

In Australia Ajax powder is easy to get.

**LINK**

In the UK "Mumsnet" Well I never!
**LINK**

Anyway there will be something sort of powder in the supermarket for aluminium pots apart from Scotchbrite,
Scotchbright should have a warning label, "Use it on glass at your peril" I know,…… an apprentice used it to clean some brand new laminated glass windows on a job one day. They all had to be replaced every one was badly scratched.
Not a good day at all. cost a fortune. You wont find it in our house.

Regards
John

[Fowlers FuryParticipant @fowlersfury]

Follow Gordon A's advice for anything where you do not want to affect the non-corroded metal surfaces e.g. reamers.

Electrolysis only converts the rust to elemental iron which collects at the bottom of the plastic tub. You do need to degrease first though and ensure you connect the rusty bit to the cathode of the battery charger !

[RainbowsParticipant @rainbows]

Wasn't sure which to go for, then I realised I could use my inverter welder as a DC powersupply, will get a £4 plastic crate and wire up some electrodes from scrap and see how that goes

[Fowlers FuryParticipant @fowlersfury]

Not that there aren't hundreds of weblinks to electrolytic derusting but here's the one I followed – now with an update about hazard of stainless steel electrodes and hexavalent chromium (which IMO is a very low risk).

**LINK**

[RJWParticipant @rjw]

Citric acid is my favourite 'go-to' de-rusting method these days, I've used various acids, have a sandblast cabinet and a dedicated power supply for electrolytic cleaning, but nothing so far has beaten Citric acid crystals for ease of cleaning, wished many a time I'd found this method earlier instead of standing for hours over a sandblast cab,

I use a 50 litre plastic crate with a clip on lid, throw in a kilo of crystals (£1 a packet from the …. erm ….pound shops), then add 20 litres of boiling water straight from the kettle or whatever quantity depending how much stuff has to go into the tank, stir up to dissolve the crystals and then chuck in anything steel or cast iron that needs a good clean …. tools, car parts, clock parts, you name it, heavy encrustations will need the odd rub with a wire brush or Scotchbrite pads, oily bits need a wash first or it makes the mix messy,

If you rinse off the cleaned parts straight away after treatment, they'll start to rust immediately unless you oil or paint them, but if you just leave to dry straight out of the tank until ready to use, the acid will dry leaving a protective film, just wash of and oil or paint etc when you're ready to deal with them,

Very satisfying to see a steady fizz of bubbles gassing off the bits when the crud is being eaten, and the best bit is that when spent the fluid can be just chucked down the drain, any debris is left in the bottom of the tank,

Beware leaving the citric in the tank unused for a while though, great gobs of mould forms on the surface of the fluid, oh and if you want to speed up the job, use a fishtank heater with an adjustable thermostat.

John

[Matt HarringtonParticipant @mattharrington87221]

Oxalic acid? Not really an acid and doesn't seem to harm the sustrate. I use 1 table spoonful in a gallon of warm water. It leave a black residue that brushes away quite easily.

Matt

[Fowlers FuryParticipant @fowlersfury]

Citric acid and rust
"Very satisfying to see a steady fizz of bubbles gassing off the bits when the crud is being eaten,"

The "fizz of bubbles" consists of carbon monoxide and hydrogen.

[RobinParticipant @robin]

I use those white crystals they sell as organic rust remover. A good soak to get down to the bottom of the rust pits, rinse, blow dry then WD40 to do what WD40 actually does, displaces water

[Geoff TheasbyParticipant @geofftheasby]

Oxalic acid is very poisonous.

Geoff

[RJWParticipant @rjw]

The "fizz of bubbles" consists of carbon monoxide and hydrogen.

Hardly an earth shattering volume compared to various pollutants created by using other forms of de-rusting, such as the energy used by sandblasting and electrolysis, especially compared to that created by various forms of air, sea and road transport, and what about pollutants created by phosphoric and other types of acids,

Every form of treatment has its eco downsides, it's up to us to ameliorate their impact on the environment, the alternative is to sit in a chair and do bugger all, personally I'll just get on with using my citric treatments, at least you can stick your hand in the stuff without them vanishing in front of your eyes.

John.

[Matt HarringtonParticipant @mattharrington87221]

Posted by Geoff Theasby on 01/12/2017 12:40:41:

Oxalic acid is very poisonous.

Geoff

Really, I thought it was found in plants. I suppose everything is poisonous in certain proportions.

Matt

[Eric ArthrellParticipant @ericarthrell78468]

Posted by Gordon A on 29/11/2017 21:51:25:

I find that electrolysis works for me on tools etc. Washing soda is dirt cheap and not much electricity is used. Search for electrolysis rust removal on the web, lots of information out there on the subject.

Gordon.

I also use the electrolysis method , I also reverse the polarity to put rust on when aging Items to make them look old .nothing worse than a reproduction item that looks brand new.

Eric

[Neil WyattModerator @neilwyatt]

Posted by Matt Harrington on 01/12/2017 13:03:05:

Posted by Geoff Theasby on 01/12/2017 12:40:41:

Oxalic acid is very poisonous.

Geoff

Really, I thought it was found in plants. I suppose everything is poisonous in certain proportions.

Matt

That's why you shouldn't eat rhubarb leaves!

It causes gout among other things.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Matt Harrington on 01/12/2017 13:03:05:

Posted by Geoff Theasby on 01/12/2017 12:40:41:

Oxalic acid is very poisonous.

Geoff

Really, I thought it was found in plants. I suppose everything is poisonous in certain proportions.

Matt

Oxalic Acid is common in plants but being natural doesn't mean it's harmless. Don't drink a gallon of home-made rust mix by accident because an ounce of Oxalic Acid has a 50/50 chance of killing an adult human.

I don't think (and haven't checked) that Citric Acid and Rust produce Carbon Monoxide. I hope not because Carbon Monoxide is very dangerous. Not as a global pollutant but what happens if you breath any in a confined space. Hydrogen isn't poisonous but the fire risk is high – you wouldn't want any going bang in your workshop.

Generally I'd suggest NOT breathing in the concentrated output of any chemical reaction if you can avoid it. Why take the risk when ventilation is so easy?

Dave

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