Acetone Questions.

It's a term I created for use in my upcoming book. It's a process where you start with the more polar solvent (water) , then move to lower polarity (acetone) and conclude with non-polar (xylene).

It's importantant to follow because of the general rule "like dissolves like". A polar surface contaminant will only be removed with a polar solvent. A non-polar surface contaminant will only be removed with a non-polar solvent.

Sometimes you have a complex surface contaminant. It could be a non-polar type over a polar type or vice-versa. By reversing the ladder, you may find a different type of solvent system now works for conservation... once the top layer has been removed.

 

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If one were to use water as a rinse, wouldn't reverse osmosis water be better than distilled? Also, as far as PF or PL how about a final steam rinse. I thought about that only because I know that fine crystal stemware recommends that and it leaves behind no water spots.

 

Not necessarily. Distilled water absolutely CAN BE better than RO water, but it depends more on how it is distilled. Where I used it, RO water was about 10X dirtier than scientifically distilled water. What I have not been able to find is the purity of "distilled" water people buy at stores. Suffice it to say that it has not been scientifically distilled, for the moment.

 

That makes sense if it's scientifically done. I've noticed that a lot of the distilled water I see in my grocery store actually comes from municipal supplies and I know from my experience keeping aquarium reef tanks that distillation alone will not remove chloramines and chlorine with first passing it through carbon filtration and that it can also tend to be acidic with a low PH, so I imagine anything you could pick up at a store has the potential to be very "unpure."

 

OK, GDJMSP. Here you go. First off, the materials you are worried about for rinsing are the non-volatiles. That is what leaves the residue behind. Volatiles evaporate (acetone and water) and leave nothing behind. The specs for acetone (selected specifications from Fisher Scientific - http://www.fishersci.com/wps/portal...ssRefData=null&highlightProductsItemsFlag=Y);

Reading http://www.potencecontrols.com/technical_library/WHAT IS CONDUCTIVITY AND HOW IS IT MEASURED.pdf, it states that distilled water contains about 5 PPM of dissolved solid (i.e. non-volatiles with calculations).

Is the distilled water "purer" than acetone? Absolutely, but it is the type of impurity that causes the problem. Distilled water absolutely contains more problem impurities than acetone.

 

What a great thread. I have been pondering many of these questions myself.

I think I will try to experiment with a bunch of ragged road kill pocket change before attempting to clean anything of value or rarity.

 

Just to clarify, is acetone safe for all metals? Gold, silver, copper, zinc, brass, nickel, etc, etc? Is there any coins that SHOULD NOT be cleaned with acetone?

 

No coin should be cleaned....but they sometimes need to be conserved. There's a BIG difference between the terms!

Yes, acetone is all metals safe.

 

If it's 100% acetone, that doesn't leave much room for impurities.

Seriously, the organic compound impurities that may be present in acetone are a completely different beast than the ionic materials present in water. That's what RLM was trying to say. Ionic materials (salts, anions) are corrosive to metals whereas organic impurities generally are not.

 

So even if the acetone is 100%, It can still be contaminated with corosives
Is that what iam hearing??

 

NO! If it's 100% acetone, nothing can be contaminating it....think about it.

That chances of you having a corrosive component in a high-grade acetone is basically zero. It's a million times better to use acetone as a final rinse than water.

 

Back in elementary school, I learned 100% = >99.5%.

However, since water is a product of the manufacturing process, and water and acetone form an azeotrope (i.e. they are very hard to separate). That is why most of the contamination of acetone is water and it is pure water because it is formed from hydrocarbons and never exposed to salts.

 

I didn't really see where this question was answered as far as what to use to safely hold the coin.

 

Your fingers! See post #12.

 

I was just wondering Bad..will your book include the actual tested results of various chemicals used on particular coins? I was wondering if it would be largely an opinion based book or practical experience using particular chemicals and their effects on particular coins. Maybe a mix of both or are you not going there at all? In other words..will you say...this chemical produces this result..I've only tried these particular methods, etc.,or will it be largely theory?
Thanks :smile

 

I think i will have to go with the guy with the plus 24,000 posts on
This one:hail: