mactuan12
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Registered: 12-1-2020
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Metal surface treatments
This thread is intended to be about decorative and/or functional chemical surface treatments for metals, preferably using OTC chemicals. Please add
your experiences.
Here's one I played with recently, to highlight some text etched into a copper plaque. Its based on the formulas I found here
Black Copper Patina
A solution of potassium sulphide applied to bare copper produces a black patina of copper sulphide. Not possessing any potassium sulphide I mixed
saturated calcium sulphide solution ("Lime Sulphur" from a garden shop) with saturated potassium sulphate solution ("Sulphate of Potash" from a garden
shop).
The quantities were very roughly equal (not good science, but then all I wanted was to blacken some copper  ). The resulting solution instantly produced a thick black non-adherent layer on clean copper. Diluting to 5% with
water worked much better, the reaction was slower (blackening over 2-3 seconds) and producing a thin matt black coat with excellent adhesion.
Polishing with fine steel wool to highlight the etching left the blackened areas shiny grey (like graphite), giving a lovely 'antique' effect.
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BromicAcid
International Hazard
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Registered: 13-7-2003
Location: Wisconsin
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Mood: Rock n' Roll
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I did some electroplating of copper on a sign at one point and treated it with 'liver of sulfur' made by dissolving some sulfur in a potassium
hydroxide solution. Worked well, just wiped it on and washed it off giving a deep deep orange/red almost black coloration.
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Armus_
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Registered: 12-11-2019
Location: whatever that burning ball in the sky is
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Mood: finnaly reached 50 elements!!!
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im not sure if it works but i have seen it happen before.
so there is a way to show the crystal structure of iron (not steel) by putting iron in a solution of copper chloride (slightly acidic) and when you
see the crystal structure then take it out, rince it off, and dip it in a hot oil solution
correct me if im wrong, im wanting to do this experiment but i never got the chance to do so
35 elements synthesized me in total
bought 15 because of toxicity issues/cant get it from household materials
3 years of this project and still working on catching them all (that's possible)
- Armus_
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