Serious Education ... plus the most fun you can have in metal finishing.
How to rust steel on purpose
^- Olivier de Géa pencil sketch on rusted steel
(see Jan. 12, 2010 entry)
^--John Dupree's table
(see Aug. 29, 2008
Q. My company provides high quality doors and windows for custom homes. Being in the mountain / mining region, rusted steel is the preferred finish of choice for many surfaces in the home. My question relates to making new steel look old. What is the best, safest, time efficient way to rust raw steel? Then of course, what is the best way to stop or slow down the process and seal the finish as to not present a problem with peoples clothing, etc., coming in contact with the steel. Then what might the process be for rusting galvanized? Thank you for your help.Richard C [last name deleted for privacy by Editor]
- Telluride, Colorado
A. You're providing high quality doors and windows that rust on purpose? A lot of us are in the business of trying to prevent what you are asking :-)
What kind of warranty can you offer!?
You could paint something to make it look like rust.
You could paint over galvanneal as well.
You could use 588 steel that would weather and seal itself, but it would streak.
If you want something to rust evenly, you may have to sandblast it to remove any scale. Your trick is to keep it rusty but also protect it from rusting away.Mike Stroia
- Canton, Ohio
Q. After searching extensively on this site as well as general search engines and finding no TRULY USEFUL advice which provides IN LAYMAN'S TERMS an answer to a question MANY PEOPLE ARE ASKING I can only assume that
1. you genuinely don't know how to cause rust, or
2. you don't "get" the question, or
3. you would prefer to "sell something to simulate rust", or
4. I am far too stupid to understand your answer.
Assuming that #4 is correct, could you please dumb it down a few notches and tell us how to make steel rust? Is it acid? Is it alkali? What is the cheapest and most commonly available chemical to accelerate the rusting process? Table salt? Vinegar? Pool acid (muriatic?)? Some SAFE combination? What do you recommend on large projects (300' of "wrought iron fence)? Architectural elements? Again, assuming that I am just ignorant, metal which I DON'T want to rust does so for free, why should it be expensive to help the process along? I understand that time is money but it shouldn't take twice the national debt of Bolivia to make steel rust. Or is the answer #1 you really don't know?
Thanks in advance,Mason D [last name deleted for privacy by Editor]
- Phoenix, Arizona
People's needs are often very different even when they use similar phases like "rust finish"; thus you criticize Mike for poorly answering the questions you had in mind but hadn't asked, when actually he answered Richard's questions very well. Richard has to guarantee that his high quality doors stop rusting; you don't have to guarantee your old wrought iron fence. Richard is very concerned about rust rubbing off on clothes, which it does -- so Mike suggested he consider rust-look paint to solve both problems ... and you say he prefers to sell something to simulate rust. Richard needs a streak-free look for his high quality doors, whereas a bit of streakiness on a wrought iron fence probably won't be noticed.
Salt plus vinegar is safe for people but quite corrosive to iron. It should work for your situation. Good luck!
Ted Mooney, P.E. RET
Pine Beach, New Jersey
A. I have "rusted" steel Bimex hinges (3" x 1") to make them look old as follows: Soaked them in metal
edge^etch for 2 hours followed by rinsing and vinegar soak overnight. Then rinsed and placed in hot salt water solution overnight. Removed and left to dry. Rust had started to form. Then occasionally sprayed them with water to increase the rusting process. Satisfied with rusty look results at end of 2 day total process. Can't see any reason why larger objects would not work with modified process.
- Sun City West, Arizona
Q. Question to Ed N you mentioned to soak pieces in metal
? could you please tell me what that product is and where I could get some? thank you so much ...I want to rush hinges as well.
hobbyist - Bingham, Maine
edge^etch is a metal etching solution I found at a hardware store. I have since "rusted steel on purpose" without this step. A vinegar soak overnight, Hot concentrated salt solution, and removal of the steel from the salt solution and allowed to dry in the air overnight. An occasional spray with water will speed the process. There is enough salt left on the steel from the hot soak. Finally wash in water, dry (blow dry) and a clear finish if desired. Results have been good and consistent.
- Sun City West, Arizona
Q. I'm replicating furniture handle for rustic living room cabinet. The original pieces are made of steel or iron wire and are fashionably rusted. I've managed to recreate the shape and size, but how do I rust it quick! In few days instead of weeks?Jay T [last name deleted for privacy by Editor]
electronics engineer - Toronto, Ontario, Canada
A. I make large quantities of rust for thermite using two different methods (depending on the quality of the steel that I'm working with):
Method 1. --------- You'll need a source of DC electricity, a tub of water and some salt (maybe a tablespoon). Connect a piece of steel to the positive output from your DC source, stick that in the water, and then stick the negative output into the water (but don't let the two touch). Switch on your power supply and let it sit, I usually do this overnight. Make sure you unplug your power supply before attempting to get at the sweet rust meats inside (I think this goes without saying). BE CAREFUL NOT TO ZAP YOURSELF!
Alternatively, you could file the metal down to a nice fine powder, and as suggested above, place in vinegar water, and then warm salt water. As I mentioned before, I use the resulting rust powder to make thermite, which I then use to cast into "permanent" moulds for casting aluminium and various other metals, though I reckon if you were to mix this powder up with some varnish, you'd have a nice "rust paint" to work with. My biggest concern, as you expressed, would be the rust contaminating "healthy" metal. Unfortunately, I don't know how to solve that, but hopefully mine and the others' information has brought you halfway there! Cheers and good luck!Andrew W [last name deleted for privacy by Editor]
Hobbyist - Grandville, Michigan
A. I am not the expert you guys seem to be. I have found that by soaking a piece of plain steel 10xx series in hot pure orange or lemon juice you can put a very nice dark tarnish on a knife blade. This makes it not only look old and antiqued but it prevents any future rusting from occurring. Maybe this method will give you some other ideas. It does a great job of anti-reflectiveness on field knives.Bill S [last name deleted for privacy by Editor]
military - Brunswick, Georgia
A. I recently had a project that required that the sculptured steel have 100 year rusted appearance.
After a lot of research and trial & error & error & error I finally found the right combinations to create 100 years of rust in two day process. I'll start with the chemicals, the amounts will very depending on your surface area. I'm basing on 4' x 4' x 1/4" steel both sides.
1 gallon Distilled Water
1 pint MEK / methyl ethyl ketone
2 pints Muriatic Acid [linked by editor to product info at Amazon]
1 half gallon 35% Hydrogen Peroxide [linked by editor to product info at Amazon] (Semiconductor Grade)
1 Cup Sea Salt, Course [linked by editor to product info at Amazon] (Table salt has Talc and will affect the final look)
1 Cup Iron Filings [linked by editor to product info at Amazon] or Ferric Oxide
1 Pair PVC protective gloves [linked by editor to product info at Amazon] "Acid resistant"
1 Box latex gloves [linked by editor to product info at Amazon]
2@ 2" to 4" PVC paint brush
1@ 2 gallon plastic bucket
1@ Plastic Spray Bottle
1@ Pizza Cheese Shaker
1@ Water Hose
1. Have your target steel sandblasted to raw metal with an even texture.
2. Find a well ventilated area with access to a water source and drain attach the hose to the water source.
3. Mix equal parts Sea Salt and Iron Filings into the Pizza Cheese Shaker.
4. Fill the plastic spray bottle with Hydrogen Peroxide set the spray pattern to mist and store in a cool dark place until needed. Use Latex gloves; this will burn your skin fast.
5. Lay the intended rusting surface face up and flat. Using rags use the MEK / methyl ethyl ketone and clean any oil, dirt off the surface of the bare metal.
6. Mix the Muriatic Acid and Distilled Water in the plastic bucket and let rest "Cool" be sure to use the PVC Gloves.
1. Using the mixed Acid and paint brushes heavily coat the surface of the steel and let stand for 15 minutes.
2. Using the water hose rinse the Acid mixture off the surface of the steel.
3. While the surface is still damp sprinkle the Sea Salt & Iron evenly over the surface of the steel.
4. Spray the salted surface with the Hydrogen Peroxide and watch the rust form allow it dry and repeat steps 3 & 4 until you achieve the desired finish.
5. Allow surface to dry thoroughly and continue to the next desired surface.
- San Jose, California
Q. I need to have a rusty finish on my small old truck models without using commercial compoundsMostafa H [last name deleted for privacy by Editor]
hobbyist - Cairo, Egypt
Q. Hey I saw someone post a question about rusting old model cars. Well, I am trying to do the same it seems the vinegar and clorox bleach isn't working just yet but I'll keep trying; my cars are diecast so it may take more than two days. Hmmmmm anyone have any ideas?michael beebe
- honolulu hawaii
May 14, 2012
A. Hi, Michael.
I don't know about Mostafa's truck models, but your diecast cars are made of zinc, not steel. Although zinc will corrode with white pits and pockmarks, it can't ever turn to rust. You would need to use an iron patinating solution if you want rust.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
A. I am an architect/builder researching aging and/or getting a patina of rust on steel and was amused by the dialogue to/from the fellow from Telluride, CO. I, too, am doing a high end house in the mountains, and will be using rusted steel in several applications, including the front door.
Those of you in the business of preventing rust, corrosion, and the apparent aging of materials used in construction have to indulge us on this issue. Telluride, like many areas of Colorado and the west has a rich history of mining, logging, and other industrial activities that are preserved (?) in the old buildings that have survived the years but are ravaged by the elements . . . rusty tin roofs and hinges, wood weathered to a light grey, paint faded where sun and rain have worked on it over time, etc.
For new construction many architects, builders and owners want to recapture the look of these materials without actually using old materials.
In my case, I want to install some rusted steel column covers and a large panel over a fireplace in a house that we are building in the mountains for a client. I have a sample of a piece of steel that has been artificially rusted that is beautiful! (sorry, guys!) the fabricator used a thin sheet of hot rolled steel and misted it with vinegar and then sprinkled salt onto it and let is sit for several days, lightly misting it to keep it moist. The color is a rich, mottled rust orange, but the surface is powdery and very fragile, so we still have the problem of "fixing" the color to the base metal so that it doesn't rub off.
So I will try the methods suggested on this site and report the success, or lack thereof, of my efforts.
I wonder if the one writer meant to say METAL ETCHANT rather than "METAL EDGE" . Etchant is also available from Radio Shack, although it is a nasty chemical and the directions need to be followed.
Adios!Tyson D [last name deleted for privacy by Editor]
- Winter Park, Colorado
Ed. note: Thank you for catching that, Tyson -- you are surely right about metal etch/etchant rather than metal "edge" :-)
May 7, 2009
Q. Tyson G, the architect, describes using white, weathered wood. How do you seal it without the wood darkening and destroying its soft greyness? I've tried all the usual varnishes and all of them darkened the light areas of wood and, worse, really darkened the darker areas to the point the wretched thing looked piebald.
Also, which sealer are you all using on rusted metal without it darkening and losing its original 'dry' appearance?
- Mannum, South Australia, Australia