Acetone and Copper

The are several threads here on the acetone-copper situation, but I have to go and train some "scientists". Jim

 

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That's not a euphemism, is it?

 

I just wonder how many people looked up soxhlet?

 

Is that like Skelly A, B or C?

 

Two chemists walked into a bar. Asked by the bartender what he wanted to drink, the first chemist ordered H20. The second chemist declared that he would like H20 too. The second chemist died.

 

And he was very pale. Cal

 

Petroleum ether, which is not really an ether, is a mix of low molecular weight aliphatic hydrocarbons. The Skellysolves are purer aliphatic hydrocarbons with A, B and C being n-pentane, n-hexane and n-heptane, respectively. So, pet ether is sort of a random mixture of the same compounds in the Skellysolves. All are highly volatile, very flammable, and vapors are explosive in presence of oxygen.

Cal

 

Don't forget that the destructive process required light, time and high humidity - they placed the acetone vessel in a water bath and let it evaporate. This created some acidic crystals which could then damage the surface.

That's a pretty far cry from how we recommend using acetone. I'd suggest working in the shade if you work outdoors and avoid days with high humidity just to be safe. Sorry Houston & the rest of the gulf coast.

 

I use acetone on copper all the time with great results. One instance where it didn't go as well as I hoped, however, is when acetone made my Wheat cent more lustrous (which isn't a bad thing, per se, but I really liked the way the patina looked).

Here's the picture prior to the acetone bath - it had this really sweet matted pearl look brought on by the verdigris. But, I left the cent in the bath for a couple days or so, given all of the gunk. Had I known the matte appearance would completely "fall" off, I would have swished it around for a few seconds instead. I sent it into PCGS and they gave it an MS 64 RB - had it not been given the acetone bath, it most certainly would have come back as an MS 64 BN. Though again, I'd prefer the original look with a BN over an RB.

 

Congratulations!

Yes, twice. Well, to be honest, it was with bronze, not copper.

 

By the way, here's what it looks like now, post-acetone and post-PCGS. Probably in most cases, it would be a good thing to have the acetone remove any sort of layering on top of the coin. In this case, you can see that it very clearly brought back more of its luster and much more of the red color, enough to get it an RB color designation. But, it made it less appealing to me.

 

jeff,

maybe 50%.

 

Takes me back to the "good old days" when I was becoming acquainted with chemical terms. We had hexane on the shelf and also had petroleum ether and what we called Skelly A, Skelly B and Skelly C "hexane". They all were aliphatic solvents with the A, B, and C separated by boiling point. I did a quick search for Skelly A, B and C and came up with this thread . I also found this old advertisement...