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The Magic Cafe Forum Index » » Ever so sleightly » » Copper Cups Patina Development - Satin vs Polished (1 Likes) Printer Friendly Version

Steadyhands
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I'm interested to hear what others have experienced. I've found the patina on my satin cups develops nice and evenly while on the polished cup it is more splotchy.

I recently bought a set of Traditional Tapered Combo Cups (satin) and after only two weeks they have a nice chocolate patina. Mind you, I've handled them several times a day and our late summer has been wet and humid. My Paul Fox VS Cups (satin) were much the same.

By comparison, the Alter Ego Chop Cup what was polished has a patina but also has a few spots on it that are shiny and rainbowish.

In all cases I used plenty of natural body oil, i.e. from my bald oily head and have been handling them very often.
BeThePlunk
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Perhaps there are spots of oil from the manufacturing. You might give them a good scrubbing with strong detergent. Also, some cups get a lacquer finish. Tossing them in a bath of lacquer finish brings them down to the unfinished metal. Because your cups are getting some patina, this second idea doesn't apply in your case.
Mad Jake
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The reason satin cups patina more evenly and quickly is because more copper is exposed. Once you polish the cups it's like closing up pores and it takes longer.


Mad Jake Sr.
For quality cups and balls, go to www.rnt2.com
Steadyhands
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Thanks for the explanation Jake.
Donnie Buckley
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In my experience, the only variable that changes a piece of copper's rate of patina is the presence of something on the surface that will either block, or accelerate oxidation. Because all copper oxidizes, whether it is polished or not. Copper is an atom (Cu - atomic number 29). When it comes in contact with an oxygen atom (O - atomic number 8), they bond together and oxidation occurs, forming CuO, or Cu2O (cuperic oxide). Nothing prevents this bond from occurring naturally. UNLESS: the copper is not evenly in contact with the oxygen. In fact, the color of copper that we all recognize is technically the result of copper exposed to, and bonding with oxygen.

Because both Satin and Mirror polished surfaces are made up of copper atoms, they will patina at the same rate, and will patina evenly, if both finishes are equally cleaned.
My Satin Finished surfaces are degreased, cleaned with copper cleaners, and then scrubbed with brushes. There are no inhibitors on their surface.
My Mirror Finished surfaces are degreased, but then polished with high-speed buffing wheels and polishing compounds. They are then dusted with powder to prevent tarnish (patina). Dusting polished parts is a common practice among metal polishers. It helps preserve the shine and prevents tarnishing.

Residual polishing compound will act like an inhibitor to a patina. You can't even see it, but it's there. If the Mirror Finished part is washed with hot soapy water and a soft sponge, almost all residual polishing compounds will come off and provide a surface that is going to patina faster, and more evenly. I recommend Dawn brand detergent for this, as it is a very strong grease remover without the other junk put into hand soaps. If the Mirror Finished part is cleaned with a copper cleaner, the patina will occur even faster, but copper cleaners will dull the shine a bit, and I don't recommend it unless the polished copper has blemishes (like fingerprints, or droplets of saliva, or some other contaminant) on their surface, and you don't have access to high speed buffing wheels, or copper polish, to clean them up.

The first clue that there are residual polishing compounds on your copper parts is the appearance of a rainbow patina. That's only going to happen when there are other contaminants on the surface of the copper. I've forced rainbow patinas on copper by experimenting with polishing compounds and heat and gotten some very pretty results.

One of these days I will set up two untouched, equally cleaned parts - one polished, one satin - and shoot photos of the progress of their patina. This would also demonstrate any differences in the end result, because the polished surface is reflecting more light, they do of course have a different appearance in sheen to the eye in the end.
Learn the form, but seek the formless. Learn it all, then forget it all. Learn the way, then find your own way. Rings-N-Things
Steadyhands
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Thanks for the in depth explanation Donnie. It gives us a great idea of what is happening.

I've no plans on cleaning or polishing either set, they can just age naturally.
Why.So.Serious?
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Yup supper in depth explanation Smile
The Magic Cafe Forum Index » » Ever so sleightly » » Copper Cups Patina Development - Satin vs Polished (1 Likes)
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