June 13, 2006
How to make steel rust quickly
As usual, a few words of caution. This is merely my attempt to impart some information that may or may not be useful. The potential dangers of following these instructions are your responsibility. Acid will blind you and scar your lungs and copper is essentially a poison. So don't get it on you or in you, or on or in anyone you don't want dead. Do not attempt this if there is any possibility that children will have access to the chemicals. Children are sneaky little monsters that love to drink poisons just to make you feel guilty when you're sitting in jail because you were a bad person who didn't think that they could pick that lock on the shed. And don't come crying to me when the EPA sizes all your assets and you end up on the front page of your local paper and all your former friends shake their heads in disgust at how you made all those spotted owls turn sickly green.
Anyway, be careful, and you might just come out of this alive and sane. Or not
Rust can be a nice finish for garden art, sculpture, and even furniture if you don't mind the stains on your carpet. For some reason, I've been asked to do it several dozen times over the past 13 years in my business
and I've worked it into a few personal projects as well.
Steel will rust all by itself, given a little moisture and time. CorTen steel will surface rust much faster, but it still takes at least a couple of months outdoors before it looks right. CorTen is alloyed with a few other things, but I think the primary element that helps the rusting along (and ironically provides future corrosion protection) is a small bit of copper.
There are commercial patina solutions for rusty steel, but they are usually pretty expensive for tiny little bottles. It's probably because of all the lawyers they have to hire to protect them from all the stupid things that people might do with their products. But by making the patina juice yourself, you might save enough money to hire your own lawyer. But probably not.
My first forays into making steel rust involved muriatic acid
, which is dirt-cheap and available at most hardware stores. Used full strength, muriatic acid will pickle
steel, removing rust and scale. However, if you treat the steel with a very diluted solution of muriatic acid, it will rust fairly rapidly. This usually takes a few treatments and a couple of days with the weather cooperating (humid and warm is best). It's not a perfect method, and it never really works the same way twice. I don't know if it's the variations in the steel, the weather, or just getting the acidity exactly right, but it always seems to take a lot of attention and messing about to get the finish right. And I always ended up with dead grass followed by mossy patches in the yard.
After several years of pursuing this method, I've found that the big trick to getting steel to rust quickly and well is to use a mildly acidic solution that has a little copper dissolved in it. I doubt that the small amount of copper used would provide any future protection against corrosion. It might even be that the steel will corrode quicker than if it wasn't treated, but I have no idea if it would make for much of a difference.
Getting some copper into the solution is easier than you might think. Muriatic acid dissolves copper, although it's pretty slow. What I did was to take about 2 feet of 14 gauge copper ground wire stripped out of a piece of Romex, wrapped it into a coil, and soaked it in about 2 ounces of Muriatic acid for a week. This will make a concentrate which should be enough for at least half a gallon of patina solution. A sturdy, unbreakable plastic bottle would be a good thing to prepare the concentrate in. Don't screw down the lid tight, or it might explode from the gasses that are created by the acid working on the copper. The fumes coming from the acid will cause rapid rusting on any bare steel nearby, so be careful where you put it. And be sure to label it appropriately. If you're as forgetful as I am, you won't even remember where you put it after a week. And it's not the kind of thing you want to sniff to find out what it is. You'll be sorry if you do. I promise.
After a few days, the solution should be ready to use. The copper wire will still be there, but you should see that the acid has chewed into it a bit. Once the acid has got some copper in it, the greenish acid/copper mixture will deposit a bright layer of copper on a piece of clean steel that you dip into it. This is a pretty cool effect, but it won't last. The coating is extremely unstable and will soon be replaced by rust. You don't really want to use it like that anyway, as it will go a lot farther and be a lot less dangerous if you dilute it with water. You may have to play with the ratio, but somewhere between 20/1 to 100/1 of water to acid/copper solution should work well. If you apply it with a spray bottle, just realize that it won't be long for the world. The acid will eat the spring in the bottle, so it will quit working after a few days. The only thing I've found that really works longer is a little plastic hand-pump Hudson sprayer that has no metal in it.
The rust will appear more evenly if your steel is very clean and free of the scale that you find on hot-rolled products (but I don't really care about that - it can look more interesting if it's not all that consistent). If you can't clean the steel properly, a more concentrated solution may work better, but be very careful. You definitely want to wear rubber gloves and eye protection, and do it outdoors standing upwind of your work. You probably want to do this even if you're using the diluted solution, at least if you care about your life.
Hot rolled tubing and hand forged sheet and round, partially ground, prior to spraying with acid/copper solution.
Time elapsed: 20 minutes
Time elapsed: 1 hour (with a second spray)
Posted by Hal Eckhart at June 13, 2006 08:51 AM
holy crap thats fast...
(jaw hit floor, goes through, hit basement, goes through, hit secret nuclear bunker, goes through, hit detonation button, sets off nukes, destroyes werld, happy now?)
The copper trick is used in gun blueing. It's copper in selenious acid solution. Produces a dark black/blue finish on steel, and a diluted solution left a while gives you a rusted finish like wrought iron.
Many other acids work as well, not just hydrochloric and selenious. (muratic) Sulfuric acid prepared the same way will produce much the same result as hydrochloric.
Sulfuric acid also works well to 'age' copper. Spray, sit a minute, rinse. Instant green.
A relitivly strong phosphoric acid solution over the course of days produces a darker finish 'rust'. By relitivly strong I mean "just slightly stronger than your current hydrochloric solution", not "naval jelly". It's pretty fragile though, definitly something you want to spray coat with a clear acrylic or similar.
One thing that needs mentioning too is proper cleaning of the piece before 'rusting' it. Oil on the surface, even sweaty fingerprints, will screw up the result.
Err. There's a stray (muratic) in there. Added a couple words to that paragraph out of place.
Meh. No more commenting before coffee.
Thanks for the comments, Jim. I've never used selenious acid (and I don't know where to find it), but I've used "Presto-Black" from Birchwood-Casey. It works great, but it costs about $100/gallon. It will also cause rusting if left on the surface without a top coat. I know it's used for gun bluing too.
Muriatic can also be used for the greening of copper or bronze. Just put a little in a plastic garbage can with your piece suspended above the liquid and leave it overnight or longer. Or use ammonia for a vivid blue. These little fish are still blue after 15 years:
>No more commenting before coffee.
Yeah, right. But if you haven't had your coffee, it's hard to remember the rules...
I'm not sure what additional ingredients Birchwood uses in their Presto-Black gel stuff, but their regular "Super Blue" is selenious acid and copper.
> Muriatic can also be used for the greening of copper or bronze.
Never done it that way myself, but I can see fuming with acid vapor being a better way. More even patina with a lower chance of screwing up and totally etching the item.
I recently, quite by accident, spilled a few drops of ferric chloride on my bench while etching some printed circuits.
The next day, two pairs of pliers which had been on the bench next to (not in ) the drops of etchant had a uniform, hard layer of rust on them.
Your local Radio Shack has Ferric Chloride in stock for less than $5 for 16 OZ.
Ferric chloride is a very weak oxidizer. The reason they use it to etch PC boards is that it eats through the thin copper reliably (it is rather reactive with copper) but isn't reactive enough with too many other things.
You'd have to use it at a 50% solution to achieve the results muriatic acid does in 0.4-0.6%.
You could almost (almost, please don't try it. That concentration is considered a mucous irritant) gargle with the hydrochloric acid used to rust those gates in a couple hours. The equivalent ferric chloride would burn very badly and probably kill you.
Question: How can I make a SHEET of GALVANIZED metal rust fast? I have tried most of the suggestions above previously & am still not successful. Thanks for any help at all.
The problem is the galvanizing. It's a layer of zinc over the steel. Muratic acid at full strength will remove it eventually, but it will also produce a lot of nasty fumes that will burn your nose and lungs. You'd want to do it outdoors and upwind. Even then, there may be some residue that makes the rustiness uneven.
Some sort of faux finish might be less toxic.
Thanks, Hal. I understand the layer of zinc. I've tried the full strength hoping for success, but as you say it is rusting unevenly. I appreciate your response.
Do any of these fast acting rusting products smell a bit like fly-spray? (I suspect my plumber of foul-play when rust suddenly appeared on the heat exchanger of a relatively new boiler).
I seriously doubt it. Muriatic acid has a nasty smell, but when you use it highly diluted, it doesn't smell that bad.
I don't know anything about heat exchangers, but unfinished clean steel can rust very rapidly all by itself, especially if it's very warm and humid. Even sweaty fingerprints can becomes visible rust overnight.
Chemicals that cause rusting won't generally be a long-term problem, because they work on the surface. If you're worried, you could wash it with baking soda and water, but it might make it look a little worse in the short run. The big thing is to make sure the environment is dry, because moisture will always cause deep corrosion eventually even without any chemicals.
hiya guys im looking at rusting the bonnet of my car its a rat look think going on. How do i go about removinf lacquer and paint then settin it off for rusting evenely, any help is very appreciative thanks
Dores anybody know how to make metal look like patina copper by using muriatic acid?
Does any one know how to make metal look lie patina copper by using muiatic acid?
this is a stupid site man
but which metal will rust faster steel,cooper,orbronze??????
Copper and bronze do not rust; they oxidize. That's not what this article is about. Copper in various forms can make steel (an iron alloy) rust faster.
Some acids will make copper alloys oxidize faster, as mentioned in the comments above.
How long it all takes is hugely variable, and dependent on heat, humidity, and the qualities of the metal that you're working with.
Great blog, i just love it
How about taking it farther?
I have these small steel cages (6" square) that I need to look like they might be centuries old instead of just colored.
I've worked with several rust and patina solutions, but in this case I really wanted to corrode the metal. Is there something
they can be soaked in for a few weeks that will corrode and rust?
I have some cheap pump pliers with dropped steel stamped on them and I want to turn them black like some of the more espenive ones. Any suggestions?
I am making a corten planter which has been, manipulated with alot of heat. My problem is that I need this planter to have a patina by day after tomorrow. I have tried straight muratic acid (too slow),muratic acid & sea salt (too slow),tri sodium phosphate (too slow). I am running out of time quickly! CAN ANYONE HELP ?
You're probably using too strong a solution of muriatic acid. It needs to be very diluted. Try about a tablespoon of acid in a quart of water. A little more or less might work better, but it's not an exact science.
But here's another problem to worry about. You say you've made a planter out of Corten. The manufacturer says that you should not let Corten be in a permanently damp situation. It can corrode even faster than plain steel that way.
I have had good luck with amonium nitrate and ferrous sulfate both.These are chemical fertilizer ingredients and fairly harmless.The best solution is partialy dissolved granuals,and applied horizontaly,and then wetting and drying,with a misting of water.I have been able to rust galvanized metal sheet with the ferrous sulfate in 2-3 applications.Wet/Dry in full sun repeated several times,seems to work the best.
I found this information while searching for a safe way to speed up rusting. I used something some years ago on brass and came out with the most amazing and beutiful results. I painted it on in layers. If I find the bottle I will return with the product name if it isn't the one below.
"Sophisticated Finishes makes a product. You brush or spray it on metal and it creates a beautiful rusted patina. It is sold at Home Depot and Michaels Craft stores." The question still remains how to prevent the rust from "eating" the metal after a few years - also so it won't rub off when touched. I create art using rusted items (usually found in odd places) and all I've been able to use is a spray coating of flat or satin polyurethane. I'm going to try Diamond Glaze - found in craft stores. This was a great site with so many great ideas. Thanks to all !! Leetta
thanks for all the great information, i am going to try the fetilizer grandual idea, if that doesn't work than it will be the muriatic acid. i do appreciate all the information, thanks jo
Your suggested rusting method worked great on our metal piece of art (hanging in our living room). Now that we have achieved the patina we desire on the rusted metal, is there something that you could suggest to be used to seal and keep that color from changing any more??
That's a very good question. I should indeed have addressed it before now.
First off, there's nothing that you can do that's impervious to time and moisture. But in a relatively dry, air-conditioned, indoor environment, even bare rusty steel should be fine as long as it's not handled much. And if you coat it with something, it will more impervious to time and handling.
The big downside is that anything you do will affect the color.
The two things I've used are:
1. Penetrol, a commercial paint additive made by Flood - you should be able to find it at any good hardware store.
2. Various forms of boiled linseed oil, either used straight or diluted with a solvent and paste wax.
Penetrol is very effective, but it leaves the surface very glossy, and it darkens the rust so much that it can look painted. Diluting it with paint thinner and wiping it off quickly will help retain the look as much as possible while giving it some protection.
There is a mixture used by blacksmiths that goes something like this:
1 lb can paste wax
1/4 cup boiled linseed oil
1 cup turpentine
1 Tb Japan Drier
Brush on very warm (it's good if you work in the sun - don't heat the mixture indoors if you like your house and/or your marriage)
Wipe off excess before it begins to congeal.
Let dry and buff.
Repeat as necessary.
One big warning here is that anything with boiled linseed oil in it (Penetrol is full of it too) is extremely likely to cause self-combustion fires due to the fact that when is dries, it creates heat. This is no problem for the steel, as it won't warm up, but if you're not careful with your rags, you can very quickly start a fire. So spread them out and let them completely dry outside, or soak them in water and seal them in an air-tight bag.
i am doing an art piece which involves leaving tinned cans to rust inside a greenhouse. There will be a watering system inside the greenhouse and also plants/grass growing inside. is there anything i could use that would not damage the plants or corrode anything inside the greenhouse including a pond pump and hose that would rust the tins faster?
Any help would be appreciated!
is there anything that is best to use on new steel coated with its mill dark finish to expedite the rusting process
There is a product sold at industrial metal sources called Permaloc. It penetrates the rust and bonds it to the steel so there is no flaking of staining. It also provides a clear finish to the project that is UV resistant.
Hi. I've got some galvanized corrugated iron used in a landscape project that I want to make dull. Not necessarily make it rust as such, but dull down the surface so it isn't so shiny and looks older. Any suggestions?? Thanks!
this string is fabulous. I am a jewelry fabricator. Creating earrings that are made of rusted steel with either diamonds or other precious stones or no stone. The ear wire is, of course, hypoallergenic silver or niobium. I was hard-pressed to know how to rust the steel wire quickly. This string is full of ideas. Thanks so much.
Brendan, This post may be to late, but the best way to dull down galvanized steel is to spray regular old table vinegar on it. It is a nontoxic acid that will corrode the zinc slightly and its darn near free. It is called pickeling and will leave the galvanized steel with a white residue which can be left or later buffed off. It works best if sprayed on while laying flat. All other sorts of acids will work too (muratic, nitric, bleach- sodium chloride) but it may kill off your garden and maybe even yourself. I have also tried lemon juice, which works the same, but is better saved for lemonade. Remember, if its sold at Home Depot, its already in your grandma's cupboard, just under a different name.
thats very interesting but i would like to know how quick it tales seult to rust metal.
Thank you all for the information! I am planning to use the technique this week for an installation made of warm pressed iron plates. Instead of using a copper wire I want to try to see if I can get pure copper powder at a specialized farmacy or something.
I bought HCL solution today. My question is:
This solution contains less than 10 percent HCL. Does this influence the mixture ratio? What percent HCL solution did you use ???
Thanks a lot, Gosse
Regular muriatic acid is somewhat diluted, but I don't remember how much. Finding the right mixture is always a guess. Do a little testing and it will give you your answer.
The easiest way to get copper in solution is to use copper sulfate, but it's a potentially dangerous chemical (as is acid) and must be used with caution. You don't need much.
Good luck and don't kill anybody!
Hi I have this new galvanized corrugated iron roof put on an old barn we want to look old and rusty great comments so far but how do you stop it from rusting even further?
> how do you stop it from rusting even further?
You could galvanize it. :)
Once it's rusted as far as you want, wash it thoroughly. You can also use baking soda and water to neutralize the acid. But this won't slow down the normal rusting process.
There are various ways to protect the surface (like Penetrol) but all of them will fail over time. Water, oxygen, and iron will produce iron oxide, and there's not much you can do except slow it down.
Thanks Hal the builder just told me the roof is atually Zincalume does this make it harder to rust
Sorry, but I have no idea. It sounds like it's supposed to be 4x more corrosion resistant, but it's not clear why that is.
Might be easier to do some sort of faux finish or patina, but that's really not my forte.
I'm creating a design portfolio and want to use sheets of rusted metal for the front and back covers. Any suggestions for me since I will probably be handling it quite frequently?
Any help will be greatly appreciated!!
The formula above with paste wax and linseed oil should work as well as anything. It won't make the rust impervious to getting on your hands, but it won't be dusty.
thanks for all the great tip's on how to rust metal. one question, can i spray on a clear coat to seal it?
I love your informational web-site! It is so nice to get different comments and views on the subject of "rusting" and "sealing". It's amazing there isn't more information out there. I found out about you a little too late. I had rusted a piece I adored and thought I would have it powder coated....BIG MISTAKE! It peeled everywhere.... I just thought I announce this so no one else makes this mistake. You mensioned something about a sealer called "Permaloc". It is listed on several industrial metal sites as you had said, but there are so many kinds... I guess it is a Brand name. Can you tell me more...Is there a specific number or name for it? Thanks again!
I want to use muriatic acid to rust a piece of wire , but there is some glass connected to the wire . Will muriatic acid damage the glass . Thanks , Bob Christ
Just dropping a piece of copper pipe into muriatic acid is a simple way to get the copper in there. It starts showing after a couple of days and will be a dark green after a couple of weeks.
I want to rust the frame of a car pretty quickly. Is there a way to rust it bad enough to cause holes. After 10 years the frame is pretty bad but what will cause it to fall apart quick.
I'm aging an Italian replica of a cap & ball Colt 1839 Texas Patterson No. 5 revolver to look more authentic for re-enactments and as a wall hanger. I've had it for over ten years and it's already doubled in value because no more replicas of this particular historic gun are being made and likely never will be because of its complexity.
Several years ago I removed the factory blue with bleach and let it rust a bit but the rust was blotchy and too evenly spaced between unrusted areas. I welcome a few places where the rust is more prominent because this is common with old guns. Before treatment I disassembled the gun, removed the insides, sealed the bore with cosmoline (vasoline), and plugged each end of the barrel to protect the new, crisp rifling. Also, the inside surfaces of the frame were coated for protection, as well as the cylinder holes and nipples. Now I'm ready to give it another "treatment' to get a more authentic surface rust brown, with black rust where the deeper rust spots are.
The final treatment will be to chemically neutralize the rust chemicals, clean everything, and lightly buff the rust off the high spots so it will look like an old holster-worn saddle gun. It will then be oiled and protected against further corrosion. Incidentally, it's also a good shooter. I see it as a work of western art in progress.
The info in this thread is unique on the web and very much appreciated. ... thanks, all.
Not sure if anyone knows the answer, but I'm a potter and have some powdered copper carbonate and copper oxide hanging around. Could either of those be a substitute for the copper wire?
What about copper ions used to clear swimming pools?
I have about 550 sq ft of cold roll to rust.
Thanks for all the great info!
My son has a science project that must be completed in less than two weeks. He wants to put 4 pieces of galvanized metal in 4 different liquids to see what happens to each one. He chose water, salt water vinegar and muriatic acid. Any thoughts on how strong to make the muriatic acid solution? Should he merely dip the metal into the solutions once a day and let it dry or simply let the metal soak all day each solution?
Thanks for the great input...
First off, you really don't want an unsupervised child doing anything with muriatic (hydrochloric) acid. It's dangerous enough by itself, but the fumes from dissolving the zinc on galvanized steel is very noxious. The fumes will also rust bare steel in the vicinity and may well destroy electronic equipment.
That being said, I'd try a very diluted mixture; maybe 5%, and do it outside. If you leave it sitting there, make sure it's somewhere that people and pets can't get to it.
This will take a while, maybe a day or two to burn off the zinc. When it's mostly gone, rinse off the sample and by the time it air dries, you should see some rust.
I have no idea about the vinegar, but the others probably won't do anything at all in two weeks except maybe rust the exposed edges.
Hi all. I did a muratic solution to get the rusted effect, about 2:1 h2o to acid. im getting a powdery white substance on parts after 2 days...did i use too strong an acid solution? I also clear coted with rust oleum clear...done it mant times, first time ive had problems. any help is appreciated. thanks
Hello, I'm looking to use a rusted steel (A366) to create a metal window system. Is there anyway to seal the rusted look, turning it into a non rusting barrier layer? I'm looking for the finish to have the rusted corten look, but not continue to rust, where the runoff would leave a rust residue on the glazing.
Thanks for your time
You can seal it, but it's only going to slow down the process. Even clean steel will eventually rust, and once the process has begun, it will continue. Wear and tear, heating and cooling, and time will eventually allow moisture and oxygen to get to the metal. Rusting can even occur indoors if the humidity is high (like in Minnesota in the summer if you don't have AC).
Thanks. Is there a sealant product that you can recommend?
The only things I've used are linseed oil and products made with it. There's a recipe (see above), if you want to try it. There must be better things out there, but I don't know what they are.
I have been searching high and low for old rusty corrigated tin siding. I found some, but they want $178 just to ship it to me!
At home depot they have new galvenized corrigated steel for a good price, but from reading this it seems as if I will not be able to "rust" it myself. Do you have any suggestions?
Hi i need sheets of rusty tin or metal for my craft projects does anyone know were to get these or even suggestions on how to rust some sheets of metal myself. all imput would be appreciated
just like larry i need sheets of rusty tin somewhere in the uk, does anybody know of a supplier. please help i know i would be no good at rusting it myself
I have a glavanized steel pipe that I need to rust fast. I sanded it to remove the coating and am soaking it in salt water. Is there a process that may work faster? or how long will it take for the pipe to rust in the salt water?
We are attempting to use an antique iron sink in a clients powder room; problem is when she blots up left over water the cool rust finish comes off. We are considering using Rust-Oleum Painter's touch in a crystal clear matte finish. Do you have any other suggestions? We don't want to make the sink shiny and new. :) Thanks!
This site is great. Still not satisfied with ideas for sealing a rusted steel sculpture I created for an interior public space, but will try the linseed recipe you suggested. Can you tell me what Japan Drier is though?
Would I be better off using a clear spray polyurathane or lacquer?
I have a galvanized can my wife wants rusted, what can I use?
Read the comments above. Do a search for "galv".
hi, as someone metioned earlier, anyone got any ideas of how to actually corrode copper for example? ive tried patina to get a nice colour, and dipped in acid with a sponged pattern to get a more textured surface, but it's just not the same! Any ideas would be fantastic, thanks! :)
I rust steel all the time, entire roofs, art projects, etc. I have developed many patinas. I sell sealers that maintain the rusted roof without changing the appearance (not shinny,they are matt) but they are not a permanent solution. The sealers basically slow down the oxidation or minimize it to the point where the rust dust is not very noticeable. The roofs need recoating every few years to prevent rust stains from getting on wood, stucco, concrete, etc. It is not a perfect solution but it is in nearly all cases accepatable because it prevents heavy stain contamination on other surfaces. By the way, it is not expensive and it is water based. Different products for interior and exterior uses. Food safe, child safe, etc are all different conditions are require different products. I also have a more industrialized emulsified coating, matt, that last longer but has a few VOC's associated with it.
i am wondering if there is a way to rust artmetal. that is a metal, thicker than foil, that is used for tooling. it comes in various colors, i have the copper color. it comes in a roll and can be cut with scissors, it is pliable and heavier than aluminum foil. i bought it at the art supply store. i want to use it in some artwork but the copper color is so shiny and new looking and i am hoping that i can get it to rust. please let me know , you all seem like rust experts. thanks
I just want to show what I was able to do with the directions that were given in this article.
I put both the acid and copper pipes in a milk container and left them there for about a week and got a black, greenish solution. I then placed a diluted solution of this in a plastic tub and within minutes you see the metal reacting. After about an hour you get a very bright, copper looking piece.
Now for me this is where it changed for me. Once you leave it to dry it gets a little darker so I had to put it back in the solution a few more times. Afterward the "rust" actually began scrapping off so I just sprayed some clear gloss enamel on it.
I really like how it came out since the enamel makes it even darker. Like it said before in the article it all depends on the quality and type of steel you use. For me this was a piece of weldable 22 ga. steel from home depot.
Thanks mate, I am going to try this out. I have to rust laser grade mild steel, so I hope it works well, and if it does I will be very grateful to you for sharing this information.
Have a good day!
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