Introduction: The Great Vinegar Experiment

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I have read many Instructables suggesting many ways to de-rust items.

I have even tried a few with variable results, so I decided that it was time to do a definitive test.

This is that test.

Step 1: The Apparatus

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This could be done using any containers but I decided to make a neat set up using cut off and inverted Coke bottles.

I had an IKEA plastic shelf that I flipped on it's side, then drilled 5 holes in it, using a step bit.

Next I cut off 5 bottles and 'screwed' them into the holes.

The caps were screwed back on tight, and everything tested for leaks with water, before pouring in the test liquids.

Step 2: The Methods to Be Tested

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I set up; One Lemon juice, One White wine Vinegar, One Cider Vinegar, One regular Vinegar and a Soda Crystal based electrolysis one.

Step 3: The Test Subjects

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I had previously left a bunch of iron screws out in all weathers to get rusty.

There was approximately 6 months rust on them.

I selected ones that seemed to have the same degree of rust to aid comparison of results.

Step 4: The Method

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The containers were filled with enough of each liquid to cover them. The electroysis one had a half tablespoon of Soda Crystals mixed with water and connected to a 12v battery charger. (+ve to the sacrificial anode and -ve to the rusty screw.)

Step 5: Bonus Test

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Since I often read that Coca Cola can clear rust, I decided to also test that liquid in a separate cut-off bottle.

Step 6: The Results

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After an overnight soak, each was removed and cleaned with a wire brush.

No electric tools were used, just a little brush up, to treat each one equally.

Step 7: How They Stacked Up

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You can zoom into the image to inspect each screw and judge for yourself the different results.

Personally I see very little difference.

The good news is that each of these methods DOES clean off rust and does get an item back to a usable condition.

There is 'maybe' just maybe, a slightly better result from the Cider Vinegar but it really is too close to call.

Coke is not really a viable option, since it costs more and does a bit less.

The electrolysis method is fiddly and shows no real benefit on this sample. Maybe it is more suited to larger items that can be immersed in large tubs, since it would be prohibitively expensive to fill a large tub with any of the vinegars.

However, by using suitable plastic bags it is possible to envelop even a large object and lay it down so that it needs less vinegar to cover it.

Step 8: Another Specific Test

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To test the bag method I placed a rusty key in a zip bag with a little vinegar.

Step 9: The Key Result

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After just a few hours and a light brush up, the difference was remarkable.

I then coated it with Olive Oil which should help stop it going rusty again.

It is quite important to oil the results of rust treatment quickly, since I have noticed that they seem to rust faster if you do not coat them.

I used Olive oil but many others should be fine. (Maybe someone would like to do a test of oils?)

Step 10: Messy Containers or Plastic Bags

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Having tried de-rusting in several different plastic containers I am now of the opinion that it is far better to use zip bags or even large storage bags to minimize the amount of liquid needed to coat the item.

The results are good and the clear up is better.

Step 11: Summary

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So this is what I think:

  • The results are simply; that all methods do clear up the surface rust.
  • The cheapest effective substance is ordinary cheap vinegar.
  • All methods still require abrasion to clean off the loose matter.
  • All methods still need further polishing or even grinding to get to bare metal.
  • The use of zip bags or poly bags can reduce the amount of vinegar needed to coat the item.
  • It is far better to not allow items to get rusty in the first place.
  • Rust can easily be prevented by storing in a dry place, using a desiccant and coating in a light oil.
  • The best effective coating is basic olive oil (no need for extra virgin).
  • Look after your items and avoid having to use any methods to de-rust.

This was a very interesting exercise for me.

I felt like I was a student in America doing a science project. (Hey kids, this may be an idea for your next one).

Step 12: Rust in Peace

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Having said that it is best not to let things get rusty, the fact is however, that we all do.

I do have a few items that require my attention.

It looks like I will be buying vinegar by the gallon....

Step 13: Addendum Feeling Pasty

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I have since tried many ways to contain the liquid whilst it works it's magic on the rust.

One such method is to make a paste.

I looked around the web but did not see what I was looking for and so I tried this method.

Step 14: Mix It Up

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I poured Cider Vinegar into a cleaned out plastic butter tub.

Next I poured in Soda Crystals.

I kept adding and mixing until I had thick paste.

Step 15: Spread the Goo

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Once I was happy with the consistency, I then spread it over a rusty hand saw.

I then left it over night...

Step 16: The Next Day

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I scraped off the crud and brushed the metal with a wire brush.

The result was a blackened but clear area.

I then tried just Vinegar over the end section and the result is as you can see in the last picture.

One conclusion is that a paste does clear rust, but is best not left on for more than a few hours.

Another conclusion is that treating metal after the first dunk and brush can help to get back to good metal.

My last conclusions are that the paste saves liquid and is good for large surfaces or vertical surfaces such as on metal legs or a panel that cannot be treated any other way.

It is definitely something to have in your rust beating armoury.

Step 17: What Next?

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I have had some encouraging feedback from this little experiment and so I have decided to undertake two more.

The first will be using proprietary products such as Evaporust or Kurust.

Please do leave a message mentioning the names of any products that you would like me to include.

The second 'experiment' will be into the best ways to prevent rust using either proprietary methods or home made ones.

The preservation challenge has already started and will run for around 3 months to allow for results to be known.

Please do follow me if you would like to know when the new 'ibles are published.

Thanks for your interest.

Comments

roadhawks (author)2016-07-12

how to remove rust from motorcycle fue

Johnathan k (author)2016-02-03

When I was in the Military I spent some time working in our tool crib. We had to keep the tools in a serviceable condition, which mean we occasionally had to "Rust-Bust"(what we called cleaning the rust off the tools) we would use brass wire brushes and Break Free CLP(Cleans, Lubricates & Protects). It really worked well. And as a Bonus it works great as a solvent for cleaning guns or to clean a rusted up nut and bolt, to get them to, you guessed it... Break Free! Hahaha

rspellicer (author)2016-02-02

Most acids will attack rust, but the trick is to use it sparingly as you did with the ziplocks. That way, the acid becomes consumed. Otherwise, once done with the rust, the acid will start attacking the base metal. I have literally shrunk a bolt from leaving it in the phosphoric acid bath too long :D. Also , try sticking with milder organic acids like acetic (vinegar), oxalic, citric, etc...

Coke, although weak, has one advantage: it contains phosphoric acid (same acid as rust remover) and converts the rust into iron phosphate, a known good barrier coating, similar to parkerizing. Dip it in oil of choice, and the phosphate will absorb the oil. If I'm not mistaken, the compound acetic acid leaves behind is acetate, not known to be a good barrier coating.

Have tried using BLO, as mentioned by Lostintime1892, on some "phosphated" bolts, and after 2 years, no signs of rust (and I live near the sea.) However, I've not set those bolts out in the elements, so not sure about durability of the BLO under those conditions. A note about BLO, the first coat dried quickly, being absorbed by the phosphate, but the second coat took forever to dry...

Lostintime1892 (author)2015-08-05

I use Boiled Linseed Oil to preserve my draw knives and other items that may lie idle for some time. It polymerizes in the presence of oxygen, and forms a pretty durable coating. Not sure about BLO out in the elements long term, but I believe it would be worth inclusion in a protective experiment.

Thanks for your comment. I have included Linseed Oil as one of the test subjects for my future 'bike.

jrotundo (author)2015-07-22

2 things....
1. there is a restoration shop in my town that I heard uses molasses for rust removal. any idea if that could be true?

2. please try a paste wax for your rust prevention. im assuming with anything being used as prevention would need to be regularly maintained.

Gregarious (author)jrotundo2015-07-26

Thanks for commenting.

Here in the UK I believe we call Molasses Treacle or Black Treacle. I have not tried that at all and do not have any to hand, otherwise I would 'give it a go'.

Since it is basically sugar, and since I have not seen a rust treatment that suggests using sugar, I am doubtful...but a test would clear that up. Maybe someone can add their knowledge to this idea?

I am including some wax based treatments in my current rust prevention experiment. If anyone has any specific formula or brand name to suggest then I will be happy to consider including them.

I will have to stop collecting treatments at the end of July, since I plan to run a 3 month test that will conclude in time for the expected 'Preserve it' contest that will end in November.

llqxb3 (author)2015-07-20

Wouldn't it be better to use mineral oil instead of olive oil in this application?

Gregarious (author)llqxb32015-07-20

Of course there are lots of oils that can help avoid rusting . Some say 3in1 others a wax mixture with mineral oil, but any are better than nothing.
Maybe you could do a great oil experiment to see which gives the most protection.
Meanwhile Olive oil is natural and definitely has the desired effect.
Do please use whatever you are happy with.

Kinnishian (author)Gregarious2015-07-21

But olive oil can go rancid, I think that is the issue?

Itsnotatumor (author)Kinnishian2015-07-25

Olive oil can go rancid because it is organic. I prefer wax and creosote to deter rust, grease on some parts and WD40 on lag screws like the author was using. I would have sand blasted the rust off.

Gregarious (author)Kinnishian2015-07-21

I love all this feedback and alternative suggestions that you are all coming up with.

It is clear to me that it is not at all clear what is the best way to prevent rust!

I have therefore started a long term experiment based on several different ways to prevent rust. I will be including home made and proprietary solutions. Of course this will need to run for a few months to get the full results....so stand by for the Great Rust Prevention Experiment, available towards the end of the year.

In the meantime ALL suggestions are welcome and I will try to include all viable suggestions.

omnibot (author)Gregarious2015-07-21

Good experiment.
I favor corn oil for diy rust prevention on stuff that doesn't need lubricant. the oil hardens after a few days and stays on better. trends to be a little sticky but just fine for wood screws.

tomatoskins (author)2015-07-20

I love instructables like this! You posed a question and showed how you got your result. Love it!

Gregarious (author)tomatoskins2015-07-20

Thanks. I am still surprised that the electrolysis method was not so much better. I shall be looking into that some more later.

corporatelab (author)Gregarious2015-07-21

Thanks. I would like to see what you come up with.

CarlTheDabbler (author)2015-07-20

Thanks for the detailed experiment.

Pirate_Prince (author)2015-07-20

Great job!

voted.

Igioteno (author)2015-07-20

Did all the screws have the same rust and same event that led to the rust?

Gregarious (author)Igioteno2015-07-20

Yes. I show them in the picture. All had been exposed for the same time and were just as rusty. I thought that important if the methods were to be compared.

Edbed (author)2015-07-20

Awesome. Really in depth and scientific.

Gregarious (author)Edbed2015-07-20

Thanks. I felt like I was back at school. If it had needed a graph then I would have done that too.

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Bio: A long time Instructables lurker.. now pleased to be an Instructables worker,...as in; doing instead of doodling. This is easier now that I am ... More »
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