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Heat treating steel for color effects


Q. I use a plasma torch for making yard art etc. I would like to know the method for heating the steel for color effects to brighten up some of my artwork. Any suggestions would be greatly appreciated.


Margaret Scott
- Minnesota, USA


A. Margaret,

If you can specify some more detail, as to the color effect you are after. I can offer some methods of coloring, they will all be earth tones though. And unless you protect the finish with some sort of clear coat, it will eventually rust and coloring will be gone. There are some ways of creating different "rust tones" if that is what you'd like to do. These can all be done with an oxy-fuel torch. I'm a master metalsmith with 25 years of experience, I have a few tricks I've learned over the years, that may be of use to you.

Best regards,

Bradford P. Maas
- Northfield, Minnesota, USA


Q. I have just come across this question and response. I'm doing Metal Art using plasma torch mainly on 12-ga sheet steel. I've looked everywhere I can think of on information on coloring the metal with heat and would appreciate any information on this technique.

Thanks in advance,

Dan Tenold
metal art - Roseville, California, USA


A. You can create colors like gun blues, black, bronze, and more buy repeated submersions while heated in oils. different oils will create different color effects. Even bacon grease will blacken steel or iron when heat treated.

david klaiber
tattoos - dayton, Ohio, USA
May 4, 2008

A. I too am a metal artist, hand cut plasma. 40 years in metal working but only 10 in arts. To get a variety of colors you have to use Cold Rolled sheet steel, gage is not that important. The cheaper Hot Rolled is darker and just can't get much color by any means.

After my piece is cut and ground smooth (or rough) using a flap disc in a hand grinder I use an oxy/acetylene torch, the smaller welding tip works best and with a low flame that sounds like the roar of a jet engine follow the edges or just apply any place you want color. Get close to your work - you want to heat only a small area at a time. Get in and get out otherwise the entire piece will take on the same color. It is hard to tell the whole story in this little reply but always happy to share a little knowledge.

There are also some chemicals that work great in coloring metals. Simply spray on and rinse off, let dry and clear coat it - you're done. They're available from King Architectural in Los Angeles and Dallas. Hope this helps a little. Don Burrous.

Donald Burrous
Oatman, Arizona USA

September 10, 2008

Q. This is a follow up question.

What size tip do you recommend and what are the settings for your Oxygen and Acetylene? I'm trying to get the gold brown and dark blue and right now all I can get is a light blue and a grey.

Any help (advise) is appreciated.

Thank You


Jack Wiseman
metal art - Helena, Montana, USA

November 17, 2008

Q. We are working on yard art and metal pieces of different kinds. We have managed to get exactly the colors we are looking for out on our pieces, but as soon as we try to apply the clear coat, the colors disappear. We cut the pieces with a plasma cutter then use an oxy-cetalyne torch to get the colors/patterns desired. We then allow the piece to cool on its own. It looks great at this point. The instant it is hit with any moisture (water, clear spray paint, whatever) the colors almost completely disappear.

Has anyone seen anything like this before? Do you have any ideas or tips for us? Thanks.

Jason Owens
- Akron, Ohio

December 10, 2008

Q. Does anyone have an answer to the "disappearance of color when sealing question" that was posted? Help! Please!

Natalie Calhoun-Duggan
- Rifle, Colorado USA

December 12, 2008

A. Hi, Jason, Natalie. This question has been answered on other threads; sorry for the delay in answering it here.

The bad news is that there may be no perfect solution to the problem, and it's because of the nature and origin of those colors. Picture the rainbow look of a drop of oil in a puddle of water. Try to "capture" that rainbow by putting a sheet of glass over the oil slick, and you will be back to the amber color of the oil, the rainbow is gone.

Although some colors are due to genuine pigmentation, other colors are only diffraction effects -- the color from oil on puddles, and the color of oil and very thin oxides on metal; these are essentially without color, but due to their particular thickness, cause a prism effect. As soon as you put another clear coating on them, they are no longer "wavelength thin" and their "color" is gone.

The good news is that some artists have reported some luck in maintaining these diffraction colors with wax or other exceptionally thin coatings. See letter 41795. Even if there isn't a perfect answer, understanding what causes the problem may help guide you. Good luck.


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

May 17, 2011

A. As to the loss of color when you clear coat. Make sure you are not using a matte finish clear coat as it will cause this to happen. Use a gloss finish clear coat and you should have better luck. I learned this the hard way.
Q. I would also like to know if anyone can tell me how to turn steel red.

Troy Borst
- Umatilla, Oregon, USA

August 25, 2011

A. Try next download free booklet on metal coloring and plating(small chapter on heat coloring of steel,stainless steel,titanium and copper:
Hope it helps and good luck!

Goran Budija
- Zagreb, Croatia

February 17, 2013appended

Q. Hello,
We are manufacturers of custom hand forged iron lighting. We have been asked in several occasions by customers that they would like a high heat torched metal finish on their chandeliers. It's described as a black color finish with variations of color tones.
If someone could advise us on how this is done I would very much appreciated.

Rebeca Anchondo
Designer/Manufacturer - Coronado, California, USA
  ^- Privately contact this inquirer -^

February 10, 2013

Q. Hi
I would like to make a plate of mild steel into a wall plaque and would like different color on the plate, what would I need to put on to make it react! Will it make a difference if I put it outside in winter, rain frost summer? And if I would like to paint some of it to stop it reacting what would I use? Would heating it up make any difference in the color of the steel? Sorry I am an amateur artist and have not idea of chemistry only colors?
If anybody could help me I would be grateful

Litte Andrews
artist - Shudy Camps, Cambridge, UK
  ^- Privately contact this inquirer -^

February 24, 2013

A. Regarding the chandelier finish, that sounds like normal fire scale from forging with a wax finish.

Regarding the protection and coloration question on the sculpture:
There are several clear varnishes, paints, and such that will work fine for protecting and stopping oxidation. The real determination is going to be what look you're after and what surface finish is on the steel to start. Galvanized is going to oxidize at a different rate than a hot rolled, and so on. Heat will create a very thin discoloration band that will easily wear away.
In short your question is a bit vague, if we had a bit more information about what exactly you're trying to do we might be able to help a bit more.

Marc Banks
- Boone, North Carolina

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