Summary for darken stainless steel Discussion
darken stainless steel is the core issue in this thread, and the replies focus on making stainless less shiny rather than truly changing its color. John Winters wanted a less reflective finish for a stainless part in a hostile environment. Marc Banks suggested heating the piece to a dull red and air cooling it, which should leave a dark, very dull surface, but he warned that the part may be too large to heat and that stainless is work-hardening steel, so this may not suit heavy-wear parts. He also mentioned coarse wire brushing as another option. Goran Budija offered two chemical approaches: very sparing oiling followed by heating to 200–400 °C, or a sulfuric acid/sodium thiosulphate/water solution at about 30 °C. Later replies asked whether that chemical bath works, and other users sought similar dulling for strips, a watch case, an urn, and a stove top, with Cliff Kusch recommending orbital sanding, passivation, or pickling for a matte grey finish.
Q. I have a piece of stainless steel that I want to darken somewhat. I chose stainless because it will be exposed to a hostile environment, but I want to reduce its shine or ability to reflect light. It has already been bead blasted which has helped a little, but I want more. I noticed some time back that while using an acid drain cleaner
⇦ on
or
Amazon [affil link] , it darkened the stainless steel drain collar (may have been chrome), but not the stainless steel sink itself, so I suppose it all may depend on the percent of nickel, etc. in the metal and/or the chemical involved. I could have the piece Teflon coated I suppose, but that is not what I am looking for. I was wondering if there were some not-so-toxic or dangerous chemicals that I could use to darken the metal. I tried the drain cleaner on a small piece of scrap from the same piece, but it did not have the desired effect.
Thanks – John
John Winters
homeowner – hobbyist – Katy, Texas
2005
A. Depending on the size, shape, and intended use of this piece this may work. First heat it up to a dull red, then let it air cool, you will have a rather dark finish and it should make most of the surface very dull. Now the two problems I can foresee with this, one it might be too big to heat, two, stainless is a work hardening steel, it needs to be formed cold before it will harden to it’s full strength (so if it is going to have heavy wear and tear, it wouldn’t be a good idea to use this method).
Alternate idea? Coarse wire brush.
Marc Banks
– Elizabeth City, North Carolina
2005
A. You can oil and then heat it to 200-400 °C (oil it very sparingly), or you can use 50 gm sulfuric / 200 gm sodium thiosulphate
⇦ on
or
Amazon [affil link]
/1 lit water solution, temp. 30 °C.
Good luck!
Goran Budija
– Zagreb , Croatia
2005
Q. John, have you tried that sulfuric acid + sodium thiosulphate solution on the stainless steel to see if it darkens it as much as you like.
Raymond Fry
– Beaverton, Oregon
2005
Q. I have a unique problem, I need to take the shine off stainless steel strips. They are used as constrained layer dampeners on coal wagons for noise reduction but are extremely reflective which draws some complaints.
It might be a big ask but any ideas for environmentally friendly solutions (besides the obvious painting and mechanical finishing). The finish just has to be dulled down a bit to lose some of its reflectance.
Paul Baxter
engineering – Newcastle, NSW, Australia
2006
A. Hey Paul,
Mechanically you could orbital sand the stainless. This will create a matte uniform finish.
Chemically you can remove the strips and have them passivated or pickled. This will turn them matte grey and a more homogeneous finish. Depending on the reputation of the shop you decide to use will determine if it is environmentally friendly or not.
Cliff Kusch
electropolishing shop – North Vancouver, British Columbia, Canada
September 17, 2009
Q. I have a wristwatch with a stainless steel case. I very much like the shape, but not the stainless steel finish. I would like it to be darkened, gun metal or darker. Do you think any of the above would work? Would the color be somewhat consistent? Thanks, Ron
Ron Packard
– Los Altos, California
2007
Q. My question is similar in nature to the above but another twist on the unusual. My husband recently passed away and we are having him cremated. My sister picked out an urn – bright copper colored stainless steel. I would like to ‘age’ it a bit or at least tone down the brightness. Any suggestions?
Sheryl Kyrisch
– Atlanta Georgia USA
August 9, 2011
Q. Has anyone tested the 50 gm sulfuric acid + 200 gm sodium thiosulphate + 1 lt water solution to darken stainless steel?
Which dilution is the 200 gm sodium thiosulphate? I got some difficulty to get the sodium thiosulphate
⇦ on
or
Amazon [affil link]
but I can get photography solutions based on that with a 2% solution in water? Is this enough?
thanks
rui
rui moreira
– ovar, portugal
October 9, 2012
Q. I have a new stove top, it’s stainless steel and way too bright for me. How do I dull this? It’s adhered to my formica counter top so can’t come off. Thank you.
Joan barry
– wareham masachusetts
February 3, 2018