Rust removal

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meatheadmerlin

Well-known member
Joined
Mar 6, 2013
Messages
107
Location
New York
I realize this is ferrous, but this seems the best place to post this.

I have been experimenting with rust removal.
My first attempt was with a rusty, unplated alen (hex) wrench.
I used distilled white vinegar and municipal tap water, maybe 2:1.
the reaction was quite noticeable and bubbled almost non-stop.
I did add a small amount of sea salt just to provide some
extra ions to the reactions.
I should say that I know my water supply to contain sulfur.
And on that note, when the final solution totally evaporated,
I think I may have made pyrite, due to golden crystals forming
in the middle region in addition to the black crust at the top
I would assume was from the carbon in the steel,
and the sea-foam green precipitate at the bottom.
The solution remained mostly transparent throughout the process.
The precipitate turned a rusty red color after sitting for a time.
I was left with a nicely cleaned tool I hope to zinc plate.

I tried a second solution and a different object.
I mixed vinegar and hydrogen peroxide (close to 8:1)
and added a dash of sea salt (non-iodized) and sulfur mineral rock.
Into this solution I put a rusty, plated socket.
I would assume the plating to be nickel or chromium based,
but don't rightly know.

At first, a layer of deep red solution developed on the bottom,
with not much evidence of fast reaction in the way of bubbling,
but after, say, a week the whole solution turned a deep red,
so much so that I could not see the socket through it.
The rust on the socket seems a bit dissolved, but the plating is intact.
This reacted so much differently from the plain vinegar
I tried with the rusty hex (alen) wrench, I'm not sure what to make of it.
The solution is now evaporating and forming a crusty deep-red to black
substance, with a slight rusty-colored skin on the surface.

I am at a loss as to what may be happening (need more chemistry study),
and I realize I have changed more than 1 variable, but
I was hoping someone could comment on the chemistry
involved in either of these processes.
 
Anyone trying to treat rust on iron should not add anything with chloride ions in it. Chloride is a catalyst for rust, ask anyone living close to the sea.

Try this... put your iron object in diluted lye and either just put a zinc plated piece of iron in contact with your object (forming a battery) or use direct electrolytic treatment with your object as cathode and another piece of iron as anode (do not let them touch), add current.

Göran
 
There are a couple of types of "rust" oxidizes of iron, red/brown/yellow rust is hard to dissolve in acids, black rust can be dissolved easier in acids, HCl can remove rust by attacking the black rust, and somewhat attacking the iron, flaking off the red rust. but unless treated this sets up the tool to rust easier, neutralizing and oils, or paint can help to protect the iron from moisture and air that will oxidize the iron, the clean iron can be passivated with phosphoric acid, similar to bluing metal or browning metal (actual a rust patina passivisation that will protect iron in the gun), used to protect iron in gun or knife metals.

Some of the rust (black rust) can be converted back to iron with simple electrolysis the.
Red rust would be very hard to convert back to iron without smelting with carbon and limestone, even then much of it would remain oxidized.

http://myweb.tiscali.co.uk/andyspatch/rust.htm
http://www.youtube.com/watch?feature=player_embedded&v=_4NmM47XUPs


you can restore some of the iron not too far oxidized, and then using phosphoric acid to passivate, (blue), or oils or paints to keep moisture and air from attacking the iron.
 
To remove layers of rust from tools, I soak them in Coca Cola, the dilute phosphoric acid works wonders.
 
meatheadmerlin said:
I used distilled white vinegar and municipal tap water, maybe 2:1. the reaction was quite noticeable and bubbled almost non-stop.
That doesn't sound right... Vinegar, even saturated with salt, shouldn't react fast enough with iron to produce a visible bubbling. Heck, even 32% HCl doesn't really react all that fast with iron.

Any chance you had something galvanized included in there? I could see zinc reacting that fast, maybe aluminum... But iron?

I would suggest restarting your experiment series with distilled water, rather than mineral-heavy tap water. You might have some really funky chemistry going on there.
 
chlaurite said:
I would suggest restarting your experiment series with distilled water, rather than mineral-heavy tap water. You might have some really funky chemistry going on there.

I am still honing my chemistry skills and only have household chemicals to experiment with.
I have to admit that I have been mixing things with poor measurement/documentation of amounts.
I know my tap water is chlorinated, occasionally has a sulfur smell, and has a good amount of minerals.
I should goto the website and get the latest quality report.

Thanks to everyone for the new things to consider.
I will have to try my experiments with more rigorous methods and better notes,
as well as hit the books a bit harder.
I am considering studying backward from waste disposal to refining.
I eventually hope to get to refining, but want to build more confidence in
my chemistry knowledge and lab skills before investing in more potent/harmful substances.
 
I used to use reverse electroplating to clean rust from cast iron parts in a bath of concentrated tri-sodium phosphate.
 
rickbb said:
I used to use reverse electroplating to clean rust from cast iron parts in a bath of concentrated tri-sodium phosphate.
TSP absolutely rocks, but good luck getting any phosphate-based cleaner nowadays.

Go ahead and risk the extinction of our entire species by breeding antibacterial-resistant bacteria by the billions with your day-to-day hand soap, with your livestock fed on antibiotics, with your "MY KID HAS A SORE EAR!" whiny moms... But effective phosphate detergents? How dare you? :roll: :lol:
 
There are tons of youtube videos and articles concerning the electrolytic removal of rust. Very, very simple. Most use 1 tablespoon of Arm & Hammer Super Washing Soda (Hydrated Sodium Carbonate = Soda Ash = Na2CO3.XH2O - at grocery stores) per gallon of tap water at room temperature in a 5 gallon bucket. They use various metals for the anode - steel, etc. The unusual thing about the process is that the parts are made the Cathode (-) and not the anode. I don't know the amperage but I think one guy was using 2A, trickle-charged, from a battery charger. It seems to work quite well with no pitting. Takes a long time, unfortunately, and also forms a sludge.

https://www.google.com/search?q=rust+removal+using+electrolysis+battery+charger&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:eek:fficial&client=firefox-a

http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/

The only problem I can think of is the possible danger of hydrogen embrittlement of the parts. At the cathode there seems to be much fizzing and that is mostly the splitting the water, producing the OH- ion, which enters the solution (makes it more alkaline) and H2 (hydrogen gas), which generally goes into the air. Some, though, enters the lattice structure of the iron and makes it brittle. It can be eliminated by controlled post-heating of the parts.

http://www.waterburyplating.com/newsite/index.php?option=com_content&view=article&id=16&Itemid=16
 
rickbb said:
Actually you can get it at Lowes Hardware, a box of pure TSP. I used it to clean my deck last spring.
What??? Pics or it didn't happen! :lol:

Seriously though, I tried to get a few ounces of it about two years ago, and I could find plenty of "TSP-like" detergents, but I couldn't find actual TSP to save my life.

I'll have to check again, clearly. :D


Hey, as an aside - In the smileys list, I see a handful of them as the actual text you would use for the smiley (including the one I just used). Does everyone else see that, or just something weird about my browser not loading the icons?
 
chlaurite said:
rickbb said:
Actually you can get it at Lowes Hardware, a box of pure TSP. I used it to clean my deck last spring.
What??? Pics or it didn't happen! :lol:

Seriously though, I tried to get a few ounces of it about two years ago, and I could find plenty of "TSP-like" detergents, but I couldn't find actual TSP to save my life.

I'll have to check again, clearly. :D


Hey, as an aside - In the smileys list, I see a handful of them as the actual text you would use for the smiley (including the one I just used). Does everyone else see that, or just something weird about my browser not loading the icons?

I can see it as well, it's not just you.
 
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