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Author Topic: What is the best way to remove or treat rust?  (Read 298926 times)

parsley

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What is the best way to remove or treat rust?
« on: 12/09/2006 12:21:50 »
I have recently acquired a large trunk for sotring things in, however the metal on the edges and corners has gone very rusty, through being sat in a cupboard for a long time.
Anyone have any ideas, or know any good ways for how I can get rid of it?
Cheers!

<i>"I just set fire to the table!"
Bring on the chemicals!</i>
« Last Edit: 08/10/2010 09:08:54 by chris »

science_guy

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Re: What is the best way to remove or treat rust?
« Reply #1 on: 12/09/2006 14:54:13 »
rust is iron-oxide, if im not mistaken.  Im not that good with chemical reactions, but i think that if you drown it in vinegar for maybe 10 minutes, than scrape the rust off, it should go away.

Anybody to correct the ameture?

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eric l

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Re: What is the best way to remove or treat rust?
« Reply #2 on: 12/09/2006 15:17:53 »
Enter "removing rust" in Google.  This gives you about 77000 hits in English.  If that is not enough, try oxalic acid, a little water and a lot of elbow grease.

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Re: What is the best way to remove or treat rust?
« Reply #3 on: 12/09/2006 18:47:08 »
The best chemical I know to dissolve rust is hydrofluoric acid HF. Here in italy is sold in dilute acqueous solution (~10%) to use with textiles. On the other hand, it's better not to use more concentrated solutions or there is the risk to attack the metal too.

If you want to use it with a piece of metal, you should find a way to make the solution in a gel or sirup form, otherwise the solution slips away and/or dries too quickly. Once, I dissolved a large amount of sugar to that solution for this purpose (but there will surely be better ways than this one); of course the reactivity is lower.

Soul Surfer

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Re: What is the best way to remove or treat rust?
« Reply #4 on: 12/09/2006 22:34:49 »
I thought the traditional method was phosphoric acid.  This is usually mixed with water sugar sugar caramel ans caffine(not an active ingredient for this use).  it is sold under trade names from many outlets one of the best known is Coca Cola  in a recent myth busting TV programme they failed to bust this one because the found that coke worked better as a rust remover than straight phosphoric acid   :-)

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Re: What is the best way to remove or treat rust?
« Reply #5 on: 13/09/2006 05:14:28 »
Here I do this all the time:: "SOAK YOUR HINGES IN DISTILLED VINAGAR OVERNIGHT! IT TAKES THE RUST AWAY QUICKLY" Non toxic safe for enviornment and works like a champ! I have much much experience in removing rust from metal!! If you cannot soak them poor some on and let stand a couple hours, depending on the degree of rust. Tools I have soaked for several days and it takes it back to the nice bare metal, be sure you treat the hinges to a nice thorough blow drying and a coat of oil or primer of your choice! Also use a little brush or scrubber in the vinegar twice during the soaking some spots will be harder to get.. How rusty are we talking here? Super thick rust you may find once vinegar does the job, rust may have eaten all the way through the hinge!!clean them thoroughly with water and brush and rinse away the black sludge you will see remaing in the water and on hinge. clean and oil! Use your judgement if you think it needs to soak longer some things do!! Good Luck!

Karen
« Last Edit: 13/09/2006 05:16:04 by Karen W. »

eric l

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Re: What is the best way to remove or treat rust?
« Reply #6 on: 13/09/2006 11:27:06 »
Problem with hydrofluoric acid (HF) and phosphoric acid (H3PO4)is that both are etching to iron, which makes the object more prone to new rust formation !  I would not use them unless I could put on a protective coating (like an anti-rust paint) immediately.  
I have good experience with oxalic acid, both in the case of rust stains on textile and rust on metal surfaces.  In the latter case, I make a paste of oxalic acid (crystals) in a little water, and rub this on (hence the "elbow grease").  Rince with ample water and dry.  If it is difficult to dry, you can use an old trick :  after rincing with water, you rince with alcohol or acetone, and next with ether.  Keep well away from fire if you do that !

daveshorts

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Re: What is the best way to remove or treat rust?
« Reply #7 on: 13/09/2006 13:28:36 »
Don't go anywhere near HF, working in a materials lab for 5 years, this was the only chemical people were actually scared of - a suggested damage limitation measure invovles an axe! If you get it on your skin it will get rapidly into your flesh and then proceed to break down your bones...

Karen W.

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Re: What is the best way to remove or treat rust?
« Reply #8 on: 13/09/2006 14:05:51 »
YAAAY Science guy...  I missed your post last night. Vinegar is correct! Sorry
I had missed yours before I posted, I was whipped!


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science_guy

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Re: What is the best way to remove or treat rust?
« Reply #9 on: 13/09/2006 14:55:45 »
Awesome! right one the first try.

never underestimate the vinegar

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Re: What is the best way to remove or treat rust?
« Reply #10 on: 13/09/2006 17:10:48 »
quote:
Originally posted by daveshorts

Don't go anywhere near HF, working in a materials lab for 5 years, this was the only chemical people were actually scared of - a suggested damage limitation measure invovles an axe! If you get it on your skin it will get rapidly into your flesh and then proceed to break down your bones...

I wrote: "dilute acqueous solution (~10%)". It's sold in most supermarkets!

I have tried oxalic acid, phosphoric acid and acetic acid (the active chemical in vinegar) and only HF works, unless the rust is thin or in a "good" composition/physical structure. Infact, rust is not a specific compound, it can vary from Fe(OH)3 to FeOOH to Fe2O3..ecc. The first form, Fe(OH)3, is the easiest to remove chemically. But try to dissolve Fe2O3 with vinegar or oxalic acid.

(I have tried).

cranial_implant

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Re: What is the best way to remove or treat rust?
« Reply #11 on: 15/09/2006 16:34:08 »
Is lemon juice good for getting rid of rust ? Or did I hear the opposite ? That it helps to create rust ?

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Karen W.

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Re: What is the best way to remove or treat rust?
« Reply #12 on: 15/09/2006 17:40:34 »
I don't know, I have never tried lemon Juice! Long time no see ian, are things going ok with you these days? I will try the lemon thingy, but have no clue one way or another about lemon..

Karen

arico08

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Re: What is the best way to remove or treat rust?
« Reply #13 on: 04/04/2007 04:19:54 »
Even at a 10% solution, you still don't want to mess with HF without proper training and protective wear/ neutralizer.  I work with it daily, between 5% and 100%. As said before, amputation might be necessary if not treated right away (first few minutes).

BillJx

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Re: What is the best way to remove or treat rust?
« Reply #14 on: 04/04/2007 07:24:16 »
Vinegar works well, phosphoric acid works slightly better because it has less tendency to attack the iron.  I wouldn't use Coke, you can buy rust remover at an auto parts store.  But vinegar is fine.  You have to leave it soak awhile.

If the rusted parts have to stay attached to something that can't be submerged in a vinegar solution, then I'd wash them with a rust remover and then paint them with a rust converter (also from the auto parts store) which converts residual specks of rust to a stable compound.

The comments about fast rusting after acid washing are correct. Acid dissolves rust but also promotes it.  And the cleaned surface will rust easily, even with the acid washed off.  When you're finished, wash it well with plenty of hot water and dry it very thoughly before it rusts.  A hair dryer is good for finish-drying.
You can protect the metal with any oil that will leave a film.  WD-40 is useless, as it will evaporate.  To remove the oil later, wash with an alkaline solution.  Alkalis tend to protect iron from rust (somewhat) and they also like to convert oils to detergents.

There's a very cool way to remove rust by submerging a part in an eletroytic bath.  Another of those things I haven't tried yet.  Try googling word combinations of rust removal and electrolyis.

Dazla

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Re: What is the best way to remove or treat rust?
« Reply #15 on: 08/10/2010 06:10:30 »
Hello
I work with clocks and often have to remove rust form old steel parts. The first step is to use a commercial rust remover, these can be baught at most hardware stores. The second method I use is Hydrochloric acid you can try to get it as pure as possable from chemical supliers or buy pool acid this is usually at least 30%. As pointed out this chemical will eat into metal as well the solution to this porblem is to soak in the acid till rust is gone then rinse well with water after that you must heat (warm) the metal this will make the metal expand and cause the pores to open. Then coat the metal in oil the finer the better. This will make the oil sink into the metal and prevent further rust. I hope this helped.   

tommya300

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What is the best way to remove or treat rust?
« Reply #16 on: 08/10/2010 12:24:17 »
I have recently acquired a large trunk for sotring things in, however the metal on the edges and corners has gone very rusty, through being sat in a cupboard for a long time.
Anyone have any ideas, or know any good ways for how I can get rid of it?
Cheers!

<i>"I just set fire to the table!"
Bring on the chemicals!</i>


Remember that when using an acid or alkali the end result to look at is a neutral PH.
Automotive rust needs to be identified whether it is surface rust or a deeper corrosion, this will dictate where to apply, front and back, how much how many times application is needed, and what sealent to use. Your question sound like you are addressing body rust.

Stay away from hydrofluoric acid it eats through tissue, metal, glass and is not very easily neutralized. Any chemicals used will only inhibit rust once rust starts it is as bad as an incurable cancer.
Phosphoric Acid is a rust inhibitor, used in the automotive business and is the strongest least toxic, vinegar is to weak but is least toxic too.
 I have not seen Oxalic Acid used so I can not defend it nor if it is easy to get, it is said to be toxic, I notice it has allot of oxygen in its fomula which leads me to believe will not inhibit oxidation just adds to it.
 Hydrochloric breaks down to a corrosive salt.

After the treatment sealing the surface from the oxygen in the air is necessary.

Ideal if you can get straight Phosphoric acid make a paste of cornstarch and water and add to it the phosphoric acid without losing the paste consistency brush it on and wait a bit rinse off with water dry and coat the area with a sealent

   
« Last Edit: 08/10/2010 12:38:54 by tommya300 »

graham.d

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What is the best way to remove or treat rust?
« Reply #17 on: 10/10/2010 08:16:55 »
I would just like to endorse Daveshorts' comments regarding use of HF. It is used extensively in the semiconductor industry because it etches (i.e. dissolves) silicon dioxide (i.e. glass) and is treated with much respect by process engineers. I am amazed it can be bought in Italy in as much as a 10% solution. You can make a very weak solution by putting teeth (acquired from a butcher, or maybe a dentist) in Hydrochloric acid - you end up with a mix of HCl and HF though the HF content is quite low; you can still etch glass with it though. Personally, I would not monkey around with HF.

There are plenty of commercial products for rust removal, many of which contain phosphoric acid.

lightarrow

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What is the best way to remove or treat rust?
« Reply #18 on: 10/10/2010 11:40:30 »
I would just like to endorse Daveshorts' comments regarding use of HF. It is used extensively in the semiconductor industry because it etches (i.e. dissolves) silicon dioxide (i.e. glass) and is treated with much respect by process engineers.
Which concentration do they use?

Quote
I am amazed it can be bought in Italy in as much as a 10% solution. You can make a very weak solution by putting teeth (acquired from a butcher, or maybe a dentist) in Hydrochloric acid - you end up with a mix of HCl and HF though the HF content is quite low; you can still etch glass with it though. Personally, I would not monkey around with HF.
Yes, it's better, if one is not used with chemistry/chemical reagents.

graham.d

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What is the best way to remove or treat rust?
« Reply #19 on: 10/10/2010 12:04:04 »
I generally keep away from the pointy hat and cauldron brigade so I'm not sure about what the concentration is. I think it is quite highly concentrated. Actually, modern semiconductor plants tend to do everything with dry etching (plasma) now so I'm not sure how much HF is used anymore. Low tech plants would use it though.

tangoblue

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What is the best way to remove or treat rust?
« Reply #20 on: 12/10/2010 18:21:32 »
SAND BLASTING!

tommya300

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What is the best way to remove or treat rust?
« Reply #21 on: 12/10/2010 21:45:16 »
I have recently acquired a large trunk for sotring things in, however the metal on the edges and corners has gone very rusty, through being sat in a cupboard for a long time.
Anyone have any ideas, or know any good ways for how I can get rid of it?
Cheers!

<i>"I just set fire to the table!"
Bring on the chemicals!</i>

Maybe if you can furnish a picture of what you see as rust and not automobile cancer
« Last Edit: 12/10/2010 22:13:08 by tommya300 »

lightarrow

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What is the best way to remove or treat rust?
« Reply #22 on: 13/10/2010 18:34:14 »
Maybe if you can furnish a picture of what you see as rust and not automobile cancer
Maybe if you had asked this question 4 years ago, it would have been better  ;)

tangoblue

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What is the best way to remove or treat rust?
« Reply #23 on: 13/10/2010 23:14:10 »
Sand blast it. that would be a lot more fun than chemicals. only 2 problems.
1. its dangerous.
2. u need /$$$$$$$

corartum

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Re: What is the best way to remove or treat rust?
« Reply #24 on: 11/01/2012 19:52:49 »
If you want to save money, you can use a sand paper and then paint it afterwards. :)

 

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