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How do you make steel Blue?


Q. Hi, I'm a college student at an art institute right now. I am currently working on a project right now and was wondering how you go about bluing steel like they do on some handguns. I hope that this site is still active and hope to hear from you as soon as possible because I came up with this idea for a project that is due next Tuesday....Thank you.

Andrew Johnson
IADT - Roy, Washington

Ed. note: the site is most definitely active. We have an FAQ about Black Oxide processes, and there are dozens of previous threads on the subject if you will patiently apply the search engine. Good luck with the project.


Q. The previous questions didn't help me out with my question. I looked through the majority of the letters that I was referred to my question on how to make steel blue like the blackening of steel process. All of the previous letters refer to the process of blackening steel using black oxide in a hot and cold method. Although similar to my question. My original question is if anyone knows how to Blue steel. I've made several inquiries at other sites along with a few powder coating factories and other places that work with blackening steel. Hopefully you can be of assistance and possibly have this be a publicly asked question that could be placed or help me forward it to a site specifically on the area of bluing and blackening of steel. Hope to hear back as soon as possible.

Thank you for your time,

Andrew Johnson [returning]
IADT - Roy, Washington


A. Bluing and black oxiding are the same thing, Andrew. If the substrate is relatively rough and matte, the topography is such that most people will call the color "black". If it is highly polished and reflective, some people will call it "blue". The oil that is applied may also enhance the reflection and the perception of the color as "blue" also, because anything reflective tends to not be called black. I have been to firearm "bluing" factories and consulted on the processes, Andew. Firearms are "blued" by polishing, followed by immersion into hot black oxide tanks, followed by oiling. Good luck.

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


If you go to a gunshop and ask for a reblueing kit. This will have the rust and blue remover and sandpaper, and pick up some WD/40. This will be used as a degreaser. Also pick up sandpaper from coarse to super fine sandpaper and rubber gloves.
Once you remove the old blue and rust, place the pieces in a vice of some sort,cut up the sandpaper in thin strips and starting with the coarse hold the end of the strips inn each hand and slide across then up to remove the marks left by the sandpaper working your way to the bottom of the piece.keep doing this with a finer till the finest grit sandpaper. It's going to take at least 10 hours. You are actually polishing the steel and there should be a mirror image. Inside your kit you should find degreaser, rust and blue remover and blue and steel wool [linked by editor to product info at Rockler]. Before putting on the blue make sure your project is free from grease. WD-40 [linked by editor to product info at Amazon].
Do the blueing outside or in a well vented area as the smell resembles urine.
Next would be to place the blue on a cotton ball and apply on the project very quickly wait a few minutes till it dries than rub Steel wool and watch it shine. Keep this process for about 5 times and each time polish with the steel wool...The trick is in the polishing. There are other ways but this is the inexpensive. But it also entails polishing.Good luck.

Francis Simon
- Elsipogtog, NB, Canada


A. You can blue steel by heat tinting (heat it to 280-300 °C) or by use of chemicals (125 gm sodium thiosulphate / 45 gm lead acetate / 1 lit water, 82 °C temp., 5 minutes). Lead acetate is poison, avoid any contact with solution! Good luck!

Goran Budija
- Zagreb, Croatia

February 28, 2015

Q. Respected Sir,
I wish to start blackening (Black Oxide) but some customers will ask for blue blackening colour. But I have no idea about it. I have learned how the process is done, but still I have not learned or understood how the blackening will be done with blue colour. Please give information so I have understanding and can try. Please give response fast.

Tejas Tretiya
blackening works - rajkot,gujrat,india

February 2015

A. Hi Tejas. While Goran has suggested two ways to add a bluish tint on steel, I'll repeat that the terms "bluing" and "black oxiding" usually refer to the same hot blackening process and the same finish. If the substrate is matte, the finish looks black because it is not reflective; but if the surface is highly polished before blackening, and oiled after blackening, many people perceive the color of the finish as "blue" rather than black and call it "bluing".

Just this past week the internet was ablaze with the picture of "The Dress" which many perceive as gold & white and others perceive as black & blue. There is a lot of subjectivity to color perception, and the general rule is that black oxiding on highly polished surfaces is what most people call "bluing".


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

Characterization of bluing steel

November 24, 2015

Q. How to do characterization/identification microstructure of bluing steel?
Will optical microscopy get a good result?

surya eko
student - Bandung, Indonesia

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