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topic 26899

What Metals Rust the Fastest (Steel, Copper, Bronze)

An ongoing discussion from 2003 but continuing through 2019; some of these grammar schoolers are probably working on their Masters by now


Q. I am 8-years old and I'm doing a science project on,"Which metals rust the fastest (steel,copper,bronze)? I know that steel will rust faster than copper and bronze, but where can I find the comparison for all three. I've read the other questions and none of them compare steel, copper and bronze. Can you please help me with some resources and answers that could support my hypothesis? Again I know steel will rust faster because copper and bronze will tarnish.

Isaiah [last name deleted for privacy by Editor]
student - Charlotte, North Carolina


A. You are young to be considering such a question, Isaiah. Steel is a refined and very useful form of the element 'iron'. Copper is an element, too. By 'element' we mean the fundamental inseparable materials of which everything in the universe is made -- i.e., things that are not compounds or mixtures of other things but are purely and completely only one thing, as determined by how many protons are in the nucleus of their atoms. There are 92 natural (found in nature) elements, with Hydrogen being number 1 with one proton, and Uranium being number 92 with 92 protons. Iron is element number 26 with 26 protons, and Copper is element 29 with 29 protons. Bronze is an alloy (mixture) of copper and the element 'Tin', element number 50.

Copper and bronze do not contain any iron, and only iron can rust (because rust is defined as iron oxide, a compound of iron and oxygen); so the answer is that steel will rust the fastest and copper and bronze will never 'rust'.

But, yes, copper and bronze do tarnish, they do corrode. But bare copper roofs last decades outdoors, and bronze statues last decades outdoors, so it is very difficult to say which of the two corrodes or tarnishes faster, but neither rusts. Good luck.

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha


Q. I am trying to find the answer to the same question. I am 13-years old. And I need these answers for my science project. I want to know what happens when copper, bronze, and steel rust? Do they break or bend easily? Can you clean it up or do you have to replace it? Also in what kind of machinery are these metals used? Cars?

destiny [last name deleted for privacy by Editor]
- riverside, California


A. Hello, Destiny. We will reword it for you to try to make it clearer. Copper is an element (you can look up 'element'). Bronze is an alloy (you can look up 'alloy') of the elements copper and tin. Iron is an element, and steel is a very useful, reasonably pure form of iron.

Rust is iron oxide, the corrosion product of iron. You can only make iron oxide from iron and oxygen; you can't make it out of copper or tin, so copper and bronze can never rust.

Copper and bronze can corrode or tarnish, however. In fact, all metals except precious metals like gold will eventually corrode back to a form very similar to the ores we find in nature. When metals corrode the surface turns to some kind of oxide or corrosion product rather than being metal anymore -- so it no longer performs the functions of metal.

Yes, it's likely to look poorly, to be weak, to bend or break more easily, to become perforated with holes. Usually you can clean the metal -- remove the corrosion products -- but there is less metal left and eventually what's left will no longer serve the original function. Cars are made predominantly of steel, but the electrical wiring is pure copper; and there may be some wear surfaces or small electrical springs made of bronze.

Good luck with your project.

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

January 6, 2008

Q. I am doing a science fair project on which metals would rust the fastest.I just wanted to know which metal would only rust the fastest between iron, bronze, copper and steel. After that question is asked I would like to know what metal would tarnish the fastest between copper and steel.

Dario S [last name deleted for privacy by Editor]
Detroit, Michigan

January 7, 2008

A. Hi, Dario. To keep your project moving forward, please try your best to express your question in terms of what has already been said. I've already explained why bronze and copper cannot rust but iron and steel can. I'll be happy to explain again if you can tell me what it is that you don't quite understand.

As for whether copper or steel tarnishes fastest, get a piece of each, shine them up with fine sandpaper [linked by editor to product info at Rockler] to remove existing rust or tarnish and get to bare bright metal, and start recording what you see, and you'll have a good science project. Best of luck!

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

February 5, 2008

Q. Hi I'm Owen and I'm ten years old and I'm doing a science fair project on metals that rust the fastest in water. This site has been very helpful to me. Would you have any suggestions on how I could get hold of a some metals for my experiment? Is there anything I could use around my house? Also, do you know any good books that could help me? I was at the library and I couldn't find a thing about it? My mum is clueless.

Owen E [last name deleted for privacy by Editor]
- Alexandria, Virginia

February 9, 2008

A. Plain steel nails would be best, Owen. Masonry nails if you have any (these are flat nails that look like long thin triangles rather than being round). Use sandpaper to remove plating or paint from whatever nails you have. If you have some painted sheet metal from an old toy or whatever, you can sand the paint off of that -- but first test it with a magnet to make sure it is steel.

Pennies are copper on their surface, and electrical wire and copper piping are pure copper. The pull tabs on soda cans are aluminum, as is aluminum foil.

The main reason for librarians is to help people find what they need from a library. Ask for help there.

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

February 15, 2008

A. Steel rusts faster.

anferneee h [last name deleted for privacy by Editor]
- Carlina, South Carolina

February 18, 2008

A. Well, yes, Anfernee. In the same sense that fresh cod or flounder will turn into rotting fish faster than fresh cabbage or carrots will. Vegetables can rot, but they can't become rotting fish. Copper and bronze can corrode, but they can't become rust because rust is iron and oxygen.

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

"Naked Eggs and Flying Potatoes: Unforgettable Experiments that Make Science Fun"
by Steve Spangler
from Abe Books
info on Amazon

"Earth Science for Every Kid: 101 Easy Experiments That Really Work"
by Janice VanCleave
from Abe Books
info on Amazon

Kids Guide to Research
from Abe Books


September 4, 2008

Q. I am also doing a science project, but mine is steel, copper, aluminum, and brass. I need help! I have looked on the internet on oxidation, but nothing comes up!

Nathan A [last name deleted for privacy by Editor]
- Bowling Green, Kentucky

September 21, 2008

Q. Yes I am 14-years old and I am also doing a project over what types of metal rusts faster. And I need help on finding a good Hypothesis! I am a hard working student but I just can't find or think of a good Hypothesis (it's for my science project)

Christian E [last name deleted for privacy by Editor]
Student - little elm, Texas

September 26, 2008

A. Christian, the first principle is writing such a project is that words have meanings, you can't ignore those meanings and bull on :-)
We've already said at least 3 times on this page alone that only steel and iron can rust and explained why:-)

As for your hypothesis, are you sure you clearly know what a hypothesis is. It's a statement that you believe to be true and now want to scientifically test. If you take a quick look at a bowl of M&M's and it strikes you that there are a lot of orange ones, you might form the hypothesis that "M&M puts more orange candies in the bags than any other color". Then you might buy 5 bags and count each color to try to prove or disprove your hypothesis, and follow it up with research and an interview with their marketing department.

For your metal corrosion project, you should pick something that attracts your curiosity and interests you for some particular reason, because that's what makes for a good project. It's hard for someone else to guess what you would be enthusiastic about, but think about it. Maybe you collect bottle caps, or old coins; maybe you're interested in classic cars but frustrated by how corroded all the parts always are; maybe you race model boats whose innards get rusty; maybe you do slot cars racing and your car hangs up due to poor electricity conduction from wear or corrosion; maybe you've built a metal wind chime; maybe when you were in kindergarten you made memorabilia for your mom but now all the gold thumbtacks are rusted and the silver ones aren't.

Find something that interests you and form a hypothesis (i.e., just a reasonable guess that you'll try to prove), then ask your teacher, parents, or librarian for help with how you can demonstrate it. Good luck.

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

October 8, 2008

Q. I'm 16 years old and I want to know if there is any other metal that can rust except iron. Its for a science project.

de-wet C [last name deleted for privacy by Editor]
student - P.E., Eastern Province, South Africa

October 8, 2008

A. Hi, De-wet. what exactly do you mean by rust? You should mean "iron oxide", which can only come from the element "iron". But there are various alloys that contain iron, like cast iron, low carbon steel, high carbon steel and stainless steels of many different grades.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

October 16, 2008

A. Hi,
My name is Amy and I am currently studying corrosion at school. Rust is a form of corrosion, that is specific to iron. Iron oxide is rust so no other metal can rust. Metals such as aluminium actually form a surface layer of aluminium oxide which protects the metal from further corrosion. There is a table known as a Standard Reduction Potentials table that lists elements in the most likely to reduce to the least likely to reduce (the least likely to reduce are the most likely to oxidise), so if you wanted to protect something made of iron from corroding (rusting) you need a 'scrap' piece of metal to be sacrificed. this metal needs to be more likely to oxidise because it is at the site of oxidation that corrosion occurs. An example of a metal that could be used is zinc or magnesium.

Amy S [last name deleted for privacy by Editor]
student - Perth, WA, Australia

thumbs up signHi Amy. If you actually understand the words you are using in your explanation, you've achieved a great understanding of the topic!


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

December 20, 2008

A. I'm doing the same thing for my project and I have feeling that steel will rust faster so for your hypothesis you should put: "I think steel will rust faster because ...." -- hope I helped.

p.s.: I'm eleven in the sixth grade.

Jasmine M [last name deleted for privacy by Editor]
- Lancaster, California

January 3, 2009

thumbs up signI am 9 and I just completed this project for the science fair. Ted's answers were very specific and helped to explain the process and the reasoning for rusting. Thank you. For my project, I used 5 glass jars, salt and hot water. I tested 5 types of metal for a week. I put one metal in each jar of salt water and waited and recorded the results after a week. I was kind of surprised by what this experiment taught me and in the process of doing this , I learned a ton of information about metals and rusting. I even learned a thing or two about rust removal that my mom was happy to hear about. Try it for yourselves it was very interesting.

Jonathan S [last name deleted for privacy by Editor]
- Ecorse, Michigan

January 15, 2009

Q. I have a science fair project and if I leave a nail in cold water and hot water will that effect the rate of rust?

Ty J [last name deleted for privacy by Editor]
Student - Warrensburg, Missouri

January 15, 2009

A. Yes, Ty, that sounds like a good topic for a science fair project. Keeping the water hot can be problematic though. Any idea how you are going to do that? Another student opted to do refrigerator temperature vs. room temperature because refrigerator temperature seemed easier to maintain than a heated temperature. But maybe your mother or father could help you put your experiment dish on top of the hot water heater? Or maybe you have an aquarium with warm water in it that you could float your experiment dish on?
Let us know how your experiment comes out. Good luck.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

January 15, 2009

Q. We are both fifth graders and are required to enter the science fair at our school. We are partners. Anyway we want to know which type of metal will rust the fastest and if it will rust within one month and a half due to our science fair is in March. We will be trying to make the rust go away with ten types of different chemicals such as bleach, rubbing alcohol, hydrogen peroxide, and nail polish remover.

We thank you for your support.

cassidi & rachel n [last name deleted for privacy by Editor]
student academics - valley springs, California

January 18, 2009

A. Hi. Soap-free 0000 steel wool [linked by editor to product info at Rockler] rusts very quickly because it is steel and it has a huge surface area, but when you say "make the rust go away", do you mean you want to remove rust with these chemicals, or you want to immerse your metal into them instead of into water?


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

April 6, 2009

Q. Hi I'm kyana and I'm 12 and I want to know when rust occurs on metals does it effect its structure/shape and also I know rust effects the appearance of a metal but why when metals rust they turn into a brownish color?

kyana b [last name deleted for privacy by Editor]
- New York

April 8, 2009

A. Hi, Kyana. Rust is iron oxide, a reaction product that is generated by iron combining with oxygen.

Where does the iron come from? -- it comes from the piece that is rusting, the piece that is rusting is losing some of itself. The area turns brownish because rust is brownish. Good luck.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

June 3, 2009

A. Hey,
I hate to tell you this but only steel and iron rust. Everything else has to be called corrosion.

Madeleine Leung
- Adelaide, SA, Australia

September 24, 2009

A. I think the science project questions are a study on oxidation. Oxidation is a chemical reaction involving Oxygen.
Rust is the common name for ferric oxide, but is also (incorrectly) used to refer to other type of oxidation/corrosion. As Ted stated only ferrous metals (those which contain iron) can rust. But nearly everything oxidizes... striking a match causes rapid oxidation of the chemicals in the match head.
Experiments involving water and metals should also take into account that tap water is never pure water (H2O), distilled water (from the store) is closer. Other chemicals present in tap water can cause widely varying results in your experiments depending on where in the world you are and how the water is treated to kill bacteria and other micro-organisms.
Footnote: Pure water will not cause oxidation (by transfer of electrons-the chemical process) because PURE water will not conduct electricity. It takes very little contamination to change this.

Hope this helped.

"Common knowledge" is what we assume the everyone else knows.

Jim Bus
- Washington C.H., Ohio

October 26, 2009

Q. I'm a sixth grader searching for an answer! My teacher wanted me to look up distilled water and I am not really sure what contents of distilled water can make metal rust, where am I going to find it, and can it really make metal and copper rust! Also, I had to take out a material for a science fair project because I don't know what type of common items are made of bronze besides statues! Can you help me?

Ellesia Turner
- Jersey City, New Jersey

October 2009

A. Hi, Ellesia. Distilled water is water that has been distilled. What that means is that regular water was put into a pot and boiled away, but the steam that it turned into was captured and cooled and condensed back to water in a fresh clean pot. Any dirt or salt or other contaminants that were in the regular water remained in the original pot, and the distilled water is now pure water.

The bronze age preceded the iron age, so there was a time when all sorts of things were made from bronze: pots and pans, plates, drinking vessels, helmets, shields, swords, tools, cell phones, and coins.

Today we have many choices for materials, and there are only a few things where bronze is a likely choice because it is heavy and expensive: statuary and knick-knacks, certain kinds of bearings, door hardware like knobs and knockers, cleats on ships, etc.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

April 14, 2010

Q. Hi,
my school has a science fair in seven weeks and me and my partner are wondering what the quickest way to rust aluminum, copper, steel, terne and zinc. The results have to be in 4 weeks from now. Thank-you for your help.

Kind Regards,

Kyla B and Jasmin P
student - Sunshine Coast, QLD, Australia

April 15, 2010

A. Now, girls: this is a discussion group, not a service that does your homework for you :-)

It's already been said more than a dozen times on this one page alone that only iron and steel can rust. Is it really appropriate to post the question that you did, rather than reword it a bit? :-)

I would suggest either immersing your metals in bowls of common household chemicals like vinegar, water, bleach (be careful with bleach and never mix it with other stuff), and coke or spritzing the metals with those liquids on a regular and controlled basis.

Luck & Regards,

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

April 24, 2010

Q. Is there any other metals that have iron in it other than steel? By the way I am 10 in 5th grade

Missa M.
student - Maple Valley, Washington

April 26, 2010

A. Hi, Missa. Cast iron, wrought iron, malleable iron, stainless steel, Invar, Kovar. . .

Good luck.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

May 15, 2010

thumbs up signGreetings. I've really enjoyed the banter so far on this subject of rust/corrosion. I co-designed a chromatic harmonica of a very high quality and price ($4000) which employed a stainless steel body produced by end milling, and later, by EDM (electro-discharge-machining). My partner (now deceased) and I ran into many unexpected problems regarding the stainless steel (SS), but also the other metals involved as well.

My partner Douglas, a classical musician and mechanical engineer, was a strong advocate of using SS for his own instruments, and first built them for himself and others in the later 1960's to early 70's based on current wood body designs. Once we partnered to build our own design, we were startled to learn SS is not as 'rustproof' as either of us expected! And oddly, it exhibited more proclivities to rust under EDM processing than the usual mechanical end milling process!

It seems that regular end milling removes SS in stages, yet basically leaves amalgamated SS surfaces intact. But EDM processing remove ANY surface particles in order to leave an exceptionally smooth surface. Both surface types have shown rust ability, but differently. The end milled bodies had tiny rust areas develop in corners where moisture could collect. The EDM body rusted areas were sort of spotted all over, as well as in corner surfaces.

We were alarmed, to speak, and through research with our EDM operator, found that the surfaces would benefit from a process called passivation, which reduces the corrosion possibility of the general surface. As best I understand it (so far), this would mean removal of exposed particles of iron on the surface, thus inhibiting rust of the exposed surface in general.

Naturally, this process would have to take place after the EDM cutting of the form, but would obviously not completely inhibit SS rust forever.

It was quite a learning experience for us, I must say. For more information, see below:

The process in metal corrosion by which metals become passive.

A type of inhibitor which appreciably changes the potential of a metal to a more noble (positive) value.

The state of a metal surface characterized by low corrosion rates in a potential region that is strongly oxidising for the metal.

Thanks to Ted and contributors for a thoughtful discussion.

Bobbie Giordano
- Tallahassee, Florida

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