Preservation of exonumia copper & bi-metallic tokens and medals

ZoidMeister

Folks,

I have picked up one or two bright shiny copper / brass exonumia tokens and medals. Some of these are satin finished, some are semi-proof-like, others have been heat treated or semi-anodized to impart an antiques or color toned finish.

Being copper, and knowing the risks associated with dissimilar metals, would you / could you recommend any kind of external preservative to ward off the "uglies" . . . . ?

I am thinking most specifically about Renaissance Wax. Has anyone tried a light application of this stuff on any finish sensitive metals? The biggest concern I have with it is not the application, but the "buffing" that is supposed to be done immediately after application. I know it is safe for other sensitive metallic and wood surfaces, but coins and exonumia is a whole nuther ball game.

What say you? Below are a couple of photos of the typical token or medal I am contemplating trying to apply some type of "preservative." Especially the shiny copper pieces that are horrifically sensitive to finger oils . . . . .

Silver, I'm not as worried about.

Thanks in advance.

Zoid

DCW

My God, please do not wax your coins! Put them in flips or capsuls and store them properly.
These medals are not nearly as hard to care for as a pet

ZoidMeister

@DCW said:
My God, please do not wax your coins! Put them in flips or capsuls and store them properly.
These medals are not nearly as hard to care for as a pet

I'm thinking that these aren't exactly coins, and no I would never do that.

Here is the concern. See that little dark spot in the center of the lower medal? Well, that's a copper disk in the middle of a brass ring. All you chemists (and plumbers) know about dissimilar metals and galvanic reactions, right?

Even well cared for copper goes south over time. And this copper has already been "exposed" to controlled damage by virtue of having been "color toned" via heat.

We all know that spots on copper eventually go south. Short of encapsulating it in desiccated nitrogen, what other preservative steps would you recommend?

By the way, if you are not familiar, British museums developed and have been using Renaissance Wax on their exhibits for nearly a century. They use it to prevent fingerprints and damage from oil. It is commonly used on museum grade woodwork, brass and steel firearms, swords, armor, and other materials that may be subject to damage or deterioration due to normal atmospheric influences. If you haven't researched that stuff, it is worthy of the read.

I am just looking to see if anyone on the forum has used it in a like-kind application.

So, I'm old and am not worried too much about 50 year preservation, but keeping these cool medals and tokens safe for the next 10 to 20 years would be nice.

Zoid

ZoidMeister

BTW, I have no way of knowing if the spots shown above were on the piece when it was manufactured, or if these are new and developing. I just want to halt them in their tracks, if possible.

All recommendations are appreciated.

Z

JRocco

Heavy mineral oil.
Sometimes through the years copper and bronze medals can get "dry" especially if they were given an acetone bath or two and I have found that a light coating of heavy...not light mineral oil gives them their life back and the coating preserves the metal. Now this is something I do and would recommend anyone thinking of doing the same to do your homework as I would not want anyone to damage their medals.
Here is an example of a piece I coated with MO

JRocco

Let me just add that the mineral oil can be easily removed with a quick acetone dip but then you are back to square one.

ZoidMeister

@JRocco said:
Heavy mineral oil.
Sometimes through the years copper and bronze medals can get "dry" especially if they were given an acetone bath or two and I have found that a light coating of heavy...not light mineral oil gives them their life back and the coating preserves the metal. Now this is something I do and would recommend anyone thinking of doing the same to do your homework as I would not want anyone to damage their medals.
Here is an example of a piece I coated with MO

All I can say, is . . . . . . . .

cardinal

@JRocco said:
Heavy mineral oil.
Sometimes through the years copper and bronze medals can get "dry" especially if they were given an acetone bath or two and I have found that a light coating of heavy...not light mineral oil gives them their life back and the coating preserves the metal. Now this is something I do and would recommend anyone thinking of doing the same to do your homework as I would not want anyone to damage their medals.
Here is an example of a piece I coated with MO

I agree! I have used the mineral oil on copper/bronzed medals with great success.

ZoidMeister

@JRocco ,

The depth perception of that medal is jaw dropping. Could you please share a little of that pieces provenance? Much appreciated.

I'm fairly certain my net worth is less than that of that piece . . . . . .

Z

JRocco

Hey ZM
This one is a beautiful piece.
If you don't mind I will copy and paste a response I made on a different board when asked this same question.
Just easier than doing it from memory. LOL

This bronze medal is huge. It measures 82 mm in diameter and 8-9 mm in thickness. Dated 1854

"Consecration of the Restored Basilica of Saint Paul Outside the Walls
Obverse: Bust of Pius IX facing left, wearing zucchetto, mozzetta, and decorative stole. Around, PIVS IX PONT · MAX ·. Below, I · BIANCHI F ·.
Reverse: Interior view of the Basilica of Saint Paul Outside the Walls, looking down the central nave towards the apse. Around the border, PIVS · IX · P · M · BASILICAM · PAVLI · APOST · AB · INCENDIO · REFECTAM · SOLEMNI · RITV · CONSECRAVIT · IV · ID · DEC · MDCCCLIV. In exergue, AL · POLETTI · ARCH · INV ·. At the base of the floor, I · BIANCHI · FECIT ·.

This Medal was issued to commemorate the consecration of the Basilica of Saint Paul by Pius IX in 1854 and was created by Giuseppe Bianchi. The reverse of the medal features a stunning three-dimensional engraving of the central nave of the reconstructed basilica. The architect of the reconstruction, Luigi Poletti, is mentioned on the reverse in the exergue inscription. The date of the consecration (December 10, 1854) is provided on the reverse using the Julian calendar (IV · ID · DEC · MDCCCLIV). The reverse inscription can be translated as "Basilica of the Apostle Paul, from the Fire to Solemnity by the Ceremony of Consecration".

Historical Background: The Basilica of St. Paul Outside the Walls was nearly completely destroyed by a fire on July 15, 1823. It is believed that the fire was caused by a negligent workman repairing the lead on the basilica's roof. The reconstruction was a major event, with various countries contributing. The basilica reopened in 1840, but was not fully completed until 1931 when the central bronze doors were installed. The transept was consecrated during the 1840 reopening by the current pontiff, Gregory XVI. The basilica as a whole was not consecrated until December 10, 1854 by Pius IX. The reconstruction work was begun under Pasquale Belli and completed under Luigi Poletti. Unfortunately, during the reconstruction, much of the original basilica and frescoes were lost. "

Here is the full obverse by the way with the pic taken next to a Merc for scale
And while I have the file open I will try to show the detail shown in a series of pics.

ZoidMeister

Damn, I would give my left [insert favorite body part here] for one of those . . . . . .

Z

ricko

That is a truly beautiful medal....Cheers, RickO

JRocco

@ZoidMeister said:
Damn, I would give my left [insert favorite body part here] for one of those . . . . . .

Z

Hey ZM
Keep your eye out for one. They do come up for sale every so often.
This is the second example of this medal I have owned.

JRocco

I will shoot you a PM but in the meantime here is another Pope Pius done by Bianchi
This one is smaller but still a little larger than a silver dollar.
But look at the detailed work....

ZoidMeister

@JRocco , your collection of papal medals deserves more that a simple "thumbs up" . . . . . . it deserves THESE . . . . . . .

Z

Knell

@JRocco
I always admire the St. Paul medal of yours. And thanks for the info about mineral oil, I will surely try that on a few of my J.Wiener medals.
Here's a uniface St. Paul medal I acquired

St Paul outside (uniface)

Bianchi medals...

St. Paul's Cathedral and St. Peter Basilica acquired from same seller, all uniface...

Thanks for the info about the medals and for sharing your photos.

By the way, there is a St. Peter's Basilica / Pope Pius IX by Bianchi with same diameter listed now on eBay

ZoidMeister

@Knell said:
@JRocco
I always admire the St. Paul medal of yours. And thanks for the info about mineral oil, I will surely try that on a few of my J.Wiener medals.
Here's a uniface St. Paul medal I acquired

St Paul outside (uniface)

Bianchi medals...

St. Paul's Cathedral and St. Peter Basilica acquired from same seller, all uniface...

Thanks for the info about the medals and for sharing your photos.

By the way, there is a St. Peter's Basilica / Pope Pius IX by Bianchi with same diameter listed now on eBay