Summary for stainless steel blackening Discussion
stainless steel blackening is the core issue here: Michael R. Guarino asked whether stainless can be oxidized so stamped names would read more clearly in black. The reply notes that stainless steel can certainly be oxidized or passivated, but those conditions are not necessarily black. It points out that proprietary anodizing processes can tint stainless various colors, including black, though the answerer was unsure whether a brush-on anodizing method exists or whether masking would be practical. The answerer says a chemical blackening process or black oxide for stainless steel sounds closer to the goal, but cautions that selectively darkening only stamped areas may be difficult. They also mention a common alternative: blacken the whole part and then relieve the exposed areas, as is done on some brass items, though that may not suit this application.
Q. I need to know if stainless steel can be oxidized and if so how it can be done. I am stamping names in stainless steel and wanting the letters to be blackened so they are more legible.
Michael R. Guarino
Manufacturer – Cranston, Rhode Island, U.S.A.
2004
A. The thing is, oxidized stainless steel isn’t necessarily black. If you look at shiny electropolished stainless steel, it is well oxidized. Passivated stainless steel is similarly well oxidized but not black.
There are proprietary anodizing processes for stainless steel that can tint it various colors, including black. But I don’t know if there is any brush anodizing processes, and masking the rest of the item may be impractical.
I think a chemical blackening process, a black oxide for stainless steel, is what you are looking for, but I’m not sure of the best way to do that in a selective area, such as masking everything else. When you see a brass lamp or a gold school ring that is blackened in the recesses, that is done by blackening the whole thing and then relieving the exposed areas. That may or not be practical for your items. No answers, just food for thought, but hopefully someone who has actually done similar parts will weigh in on the practicalities and impracticalities of darkening your stamped names.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
2004
Q. Michael, did you find a way to oxidize letters indented in stainless steel?
I would really appreciate knowing what you have discovered… Lucy
Lucy Lukas
– Indiana
August 19, 2008
A. You can use a sharpie marker to fill in the indentations, then buff the rest off with a polishing cloth. Easy peasy.
Pamela Gangler
– Arizona
October 28, 2012