Heat treating steel for color effects

A. Margaret,

A. 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,

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

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⇦ (tip: readers rarely show interest in abstract questions, but people's actual situations usually prompt responses)  

I wanted to ask you more about Bacon Grease and how it affects the color change of steel.

mohammad mahdi
student - tajikestan
December 28, 2021

A. Hi mohammad mahdi. David's posting was from almost 18 years ago so it's unlikely he will respond, but I think he's suggesting that it will blacken steel when it's heat treated. Please describe your actual situation; abstract questions usually don't get us very far :-)

Thanks & Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 2021

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.

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

A. Hi, Jason, Natalie. This question has been answered repeatedly 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 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 actually without color, but due to their particular thickness they cause a prism effect. As soon as you put another clear coating on them, they are no longer "partial 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.

Regards,

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.
thanks

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

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.

A. Hi Joshua. Assuming this tube goes in your mouth or has vapors passing through it, I don't think you should quench in any petroleum product as they are all poisonous. It's probably de minimus, and I've even read of old-timer self-healers taking a tiny sip of kerosene mixed into their potions, but still.

I wonder what happens if you quench in mineral oil?

Regards,

Q. Ted, I appreciate your response and understand your concern. And trust me if it was the part that I use to vape through with my mouth or the liquid in I wouldn't even attempt to do it and would advise anyone else not to because that should be left to professionals. But that isn't the part that I want to heat treat. The part I want to change the colors on is where the battery goes. It's the lower part where the atomizer goes. I know that once it's done I have put a clear coat on so it doesn't fade away. I know the procedure is to wash it thoroughly, sand it so that once it's heat treated and dipped in the oil it'll absorb better, and then use the clear coat. My question is mainly that certain oils change it to a particular color. I'm not sure which oil to use so it'll turn blue or which would turn it almost black.

A. Try Everbrite [a finishing.com supporting advertiser] clearcoat, or if you are rich man try special nanotechnology coating (german product =1000 USD/1 lit). Heat tinting colors are very, very thin and that is real problem. Hope it helps and good luck!

A. I've been making heat colored steel engravings for nearly 30 years. I've successfully used several products for clear coating.

Sculpt Nouveau makes something called Colorloc which is designed specifically for preserving heat colors.

My current favorite product is Permalac NT [adv: Permalac on eBay]. It goes on easily, preserves the colors on steel, and provides a durable finish.

A. Thanks Jeffrey!

Readers: Jeffrey has a very interesting site at jeffreyhdean.com which you might be interested in visiting. Because we can thus easily verify who he is, we made an exception and have posted his testimonial, but in general we discourage testimonials or evaluation of proprietary products for a host of reasons (why?).

Luck & Regards,