I just bought a bottle of Renaissance wax

I have several Roman Bronze coins and I have tried Carnuba wax. But some here have suggested Renaissance wax. Once used how long does it last?

 

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Never tried the liquid version from a bottle. Mine is a wax in a tin that you apply very sparingly, let it dry for a few minutes and then gently buff it to a finish. It is to keep moisture from forming bronze disease, also it will highlight some of the duller areas on the coin. For example making some of the legends more readable.

 

The only drawback is that if there is active bronze disease, somewhere on or even within the coin, it can make things much worse.

 

How is that? I know some say that it might not help with preventing/slowing BD but how does it actively make it 'much worse'?

 

Absolutely correct. Should only be used when there is no evidence of BD. The reason being that it will then be contained underneath the layer of wax. Of course, then you only have to watch that coin get worse and not worry about it contaminating any others in the vicinity.

 

I have a small tin. I use it from time to time, usually on coins I've had to clean or coins in poor condition (as @expat says it can help bring out subtle details.)

It smells pretty strongly when first applied, but the smell fades overnight. I will often blow on the coin with a hair dryer before application to both warm the coin and dry off any lingering moisture.

 

Here's what puzzles me about this. As I understand it the BD reaction needs three things to keep going - the chlorides, moisture, and oxygen. Deny one of those three prerequisites and it halts the process.
Rennaissance Wax claims to seal the surface and prevent contact with moisture. Which is what wax coatings typically do. Wouldn't this now deprive the BD access to moisture, and possibly O2 as well? Why wouldn't this halt the reaction?

 

I'm also puzzled by how it happens with a barrier between oxygen & coin, but I've also had BD develop underneath. (But rarely, couple times in hundreds, maybe thousands.) I guess the barrier is imperfect and there are still microscopic spaces that allow oxygen to enter.

Lately I've only used it for fragile/crumbly surfaces to shore them up & give more "structure."

As far as I can tell, once applied, it's still there >10-20 years later (the period when I used it). It looks "matte" after a few years but turns glossy again when rubbed with a cotton swab. Comes off very easily with acetone.

NOTE: If poorly applied it can end up as waxy buildup and/or get gross and crackly over time.

TOP IMAGE: Old cracked excessive wax on a silver Corinth Stater. BOTTOM: After removal, maybe a thin layer remaining, much more attractive (especially Athena).

 

As far as I am aware, it is porous to oxygen, an inhibiting coverage for sure, but not completely so.

 

I experimented on some lower grade coins with Renaiassance Wax.
Here's a thread here where you can see some before and after pictures. As shown, here, it can be useful for removing fake patina:

https://www.cointalk.com/threads/micro-crystalline-and-appearance.352325/#post-3961723

I haven't seen an example where it improves the coin better than using a dry soft toothbrush.

 

Just don't eat the stuff........

I'll go stand in the corner. Been an most difficult day.

 

Sorry to hear @green18 - best wishes.

 

Most kind, my friend.

 

In my previous employment I was called upon to do conservation on metals. I do not advise Renaissance Wax. Apart from sealing moisture against metal, it does very little to preserve coins. Museums did used to use it - but on furniture, not coins. The best way to conserve coins is very simple - keep them in a dry environment and take professional advice from a metals conservator if you spot issues!

 

I use WD40 and Rigs grease dissolved in the WD. Works great on firearms to keep the metal rust free. But I have been told that Reinsurance wax was the thing to use on coins.

 

The reason a lot of ancients collectors use it is precisiely because the British Museum use it for their copper/bronze coins with no adverse effects. They do not use liquid version from bottles though.

 

Can't you soak the Bronze in baking soda and water than bake the coin to remove all the water then apply the wax or oil?

 

The baking soda part is not a good idea at all.

(Except as part of cleaning a coin that has stubborn encrustations, and even then you have to be careful. Too much or too long and the patina will be damaged.)

 

Aside from papers on the topic, the British Museum's online catalog lists many metal objects as having been treated by Renaissance Wax, including coins. I'll link a couple (the conservation report link mentioning Ren Wax, then the coin link for the "Related Object"):

https://www.britishmuseum.org/collection/term/66738:3
Caligula Provincial Billon/Base Silver Tetradrachm: https://www.britishmuseum.org/collection/object/C_1842-0726-4

https://www.britishmuseum.org/collection/term/10601:1
Bronze Renaissance Medal (1486): https://www.britishmuseum.org/collection/object/C_G3-IP-3

https://www.britishmuseum.org/collection/term/24215:1
Hunnic / Sassanid type Silver Drachm: https://www.britishmuseum.org/collection/object/C_1894-0506-201

There are countless more coins listed with similar treatments. (And figurines, swords, as well as stuff like furniture & marble busts, etc.)

That's not to say the general point doesn't stand. There are certainly those who argue against its use on bronze objects.

This paper argues against it:
Danal Moffett, 1996, "WAX COATINGS ON ETHNOGRAPHIC METAL OBJECTS: JUSTIFICATIONS FOR ALLOWING A TRADITION TO WANE" in Journal for the American Institute for Conservation.

 

What about baking the metal coin and putting the Renaissance wax on right after? seal it up when its dry?