Summary for potassium sulfide blackening Discussion
Blackening with potassium sulfide is discussed as a way to turn copper bluish-black for tooling work. Margaret Williams asked what her friend had mixed with the yellow rocks labeled potassium sulfide, how it was used, and whether gloves were needed. Goran Budija answered with a specific formula: 10 g potassium polysulfide in 1 liter of water, used at about 80 °C, and stressed that the solution must be fresh and the work must be free of oxide and grease. A second answer added a basic safety reminder: gloves and goggles are the minimum protection when working with any chemical. The thread does not describe the full procedure beyond that, but it clearly points to a fresh hot sulfide solution for blackening clean copper and emphasizes basic protective gear.
Q. A friend of mine is teaching me how to do copper tooling, she is up in years and forgot some of what she did, like she gave me a bottle with a few yellow rocks, on the bottle the label reads potassium sulfide, she forgot what she mixed this with or how she mixed it and how she used it once it was mixed. Do you need to use gloves when working with this chemical? I think it was used to change the color in areas to black. If you could help me I would appreciate it
Margaret Williams
– Tucson, Arizona
2003
A. Bluish-black for copper:
1 lit. water
10 gm.potassium polysulfide
temp. 80 °C
Use only fresh solution! Work must be oxide and grease free!
Goran Budija
– Cerovski vrh Croatia
2003
A. Hi Margaret. Gloves and googles are the minimum level of protection for working with any chemical. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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