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Bronze turning green

RobertM

Junior Member
Joined
Feb 6, 2019
Messages
38
Old bronze coin turning green. Is there a way to stop the green from coming back?
 
This product is the one I use to stop/slow down bronze disease.

You may have to Google the product to see if it can be purchased locally?
 
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Thank you. Probably hard to find in Hong Kong. Everything is difficult to find here. :(
 
Old bronze coin turning green. Is there a way to stop the green from coming back?

Research bronze disease and archaeological preservation of cupreous metals.. simply covering the coin with Renaissance wax won't stop the progression..
 
Research bronze disease and archaeological preservation of cupreous metals.. simply covering the coin with Renaissance wax won't stop the progression..

It is my understanding that the British Museum uses Renaissance Wax to slow bronze disease, so it must be of some help. It may be something that cannot be completely halted.
 
It is my understanding that the British Museum uses Renaissance Wax to slow bronze disease, so it must be of some help. It may be something that cannot be completely halted.

You really need to research actual bronze disease..it can be stopped..but the wax definitely won't..there is more than one method..there is a method using zinc..and a method using cancerous agents as well.. I urge you to just start by reading about bronze disease to understand what it is..
 
You really need to research actual bronze disease..it can be stopped..but the wax definitely won't..there is more than one method..there is a method using zinc..and a method using cancerous agents as well.. I urge you to just start by reading about bronze disease to understand what it is..

If this is Chloride corrosion then it can NOT be stopped until ALL the Chloride is removed.
That is why it is called a disease. Sealing the object does not stop it.

Read the "Conservation of Archaeological Resources" PDF, section on "CUPREOUS METAL CORROSION" in this thread for details of what and how.
https://metaldetectingforum.com/showthread.php?t=263378

Thanks for the info guys!
 
Thanks for the info guys!

You're welcome.. trying to restore your finds adds a new dimension to detecting in my opinion..but it seems like each coin has to be individually evaluated for the various choices of approach..yes I've done irreparable damage to coins..it's how you learn..or I do anyway..but the different soil or beach characteristics combined with different levels of coin condition and metal composition create a situation where no two items can get the exact identical treatment..exposure time, chemical strength, etc..it's science for certain but also very much an art..you will develop your own style..especially the finishing.. I just try to make the coin look appealing to myself..if others like it then great..if not then I am not insulted.. every little step involves scrutiny and risk..even simple lemon juice can dissolve metal..but as you will find in research there are additives to prevent lemon juice etching..and six ways to skin the cat..lots of things will work..just as people have different preferences for an electrolysis solution.. I like sodium carbonate in my set up...and you can combine it with sodium bicarbonate to make your own sodium sesquicarbonate for artifacts..
 
I like sodium carbonate in my set up...and you can combine it with sodium bicarbonate to make your own sodium sesquicarbonate for artifacts..

I am in the process of soaking a bridal rosette and a clock part in a sesquicarbonate solution at the moment as well as some copper pieces. I figure a few days in that should help. I am going to try soaking in Benzotriazole and ethanol (some Everclear) mix for a few days as well to soak into the cracks and add a protective layer. Any thoughts for the last coat? I am going to post a thread in a few minutes as I am not sure if I should add an acrylic lacquer (water based) or clear enamel from Rustoleum (oil based) for the final of these bronze, copper, or brass pieces that are getting bronze disease from being dug up in a marsh/ sodium heavy area. Any thoughts?

I have Renn Wax but hate how much it costs. I plan to save and use only on colonial coppers and flat buttons. Just the little really old stuff.
 
I am in the process of soaking a bridal rosette and a clock part in a sesquicarbonate solution at the moment as well as some copper pieces. I figure a few days in that should help. I am going to try soaking in Benzotriazole and ethanol (some Everclear) mix for a few days as well to soak into the cracks and add a protective layer. Any thoughts for the last coat? I am going to post a thread in a few minutes as I am not sure if I should add an acrylic lacquer (water based) or clear enamel from Rustoleum (oil based) for the final of these bronze, copper, or brass pieces that are getting bronze disease from being dug up in a marsh/ sodium heavy area. Any thoughts?

I have Renn Wax but hate how much it costs. I plan to save and use only on colonial coppers and flat buttons. Just the little really old stuff.

The Benz with everclear is supposed to seal it.. I use everclear too..

I never tried oils or acrylic laquer.. I know acrylics are suggested after using Benz.. I do like renn wax... I know some guys don't but I do..it does seem expensive in respect to the volume..but a little goes a long way.. I guess it depends on how much surface area wether or not it's economical..or how many nooks and crannies there are.. Rust-Oleum would be easier to apply and cheaper on big items or ones with hard to reach places

There is a method I read about using a zinc solution for bronze disease but I haven't tried it yet..

Please post some pics and your knowledge.. I always seem to learn by mistakes..I'm always willing to try new methods..but it's nice to hear and see other peoples results in effort to improve my own
 
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