91% Isopropanol is good?

Jdurg

Earlier today I received 3 Roosies that I had been waiting for. A 1954 proof which is remarkably toned, a nice clean 1955 proof, and a 1959 proof. (Pictures of the 54 and 55 are in my other thread). Sadly, the 1959 proof came in a PVC flip and you could easily see some nasy white 'gunk' on the surface, and even a fingerprint was visible if you looked at it right. I went looking through my 'stuff' and saw that I didn't have pure acetone, only a bunch of mixtures that had a lot of solvents in there which I wasn't too keen on putting near my coin. The last thing I looked at was a bottle of 91% isopropyl alcohol. I thought for a moment and decided that it might be a good thing to use. It's halfway between a polar and nonpolar solvent, so it should be able to dissolve polar organic compounds like grease and PVC residue, yet it will also dissolve in water so it can easily be washed away. I decided to give it a try. I dipped my proof in the alcohol for a few seconds and swished it around. I then ran it through some Brita Filtered water for a good ten minutes. (Nice, clean, cold water). I then took a Q-Tip and soaked up any standing water and let it air-dry on a piece of cotton. Then I took pictures. The first picture is of the coin as I got it, and the second picture is how the coin looks now that it has dried. Looks a bit better, doesn't it?


PVC Gunk


Nice Looking

100proof1957

Ah well,NO

Not to me,but im clueless.

oreville

Looks nice, actually!

Jdurg

<< <i>Ah well,NO

Not to me,but im clueless. >>



Hehe. With your history and knowledge with Roosies, I think if I ever showed a picture of a Roosie that I owned which you thought looked good, I'd feel like a little kid again.

Nickelback

It looks okay to me also, but is the question "gunk vs. tone?" Is there a preferred solution for coins like this (newbie I am)? And by the way, whats the best way to prepare a raw coin that may only have a few fingerprints when submitting for grading? Thanks.

Jdurg

Well, on my coin there really wasn't much toning on it, just one orange spot between the C and A of 'America' on the reverse. Looking at the before and after, that toning remained there. The alcohol was just able to remove the white PVC junk that hadn't bonded to the metal's surface yet. Alcohol and acetone shouldn't remove any toning since the compounds that cause toning are generally non-solube ionic compounds. Therefore, they would not dissolve in the polar nature of acetone and concentrated alcohol solutions. Only organic compounds will dissolve in organic liquids. (I.E. acetone, 91+% pure isopropanol, methanol, etc.). I plan to watch this 1959 closely over the next few days to see if any nasty side-effects develop. (I was kind of in a win-win situation with this coin. If I dip it and it works, then I get a nicer looker coin. If it doesn't work, then I would have needed to upgrade this coin anyway so I really couldn't lose. I also didn't spend a heck of a lot on the coin so I wasn't putting a fifty dollar purchase at risk).

100proof1957

It just looks whizzed to me.

And is not PVC generally green ?

BAJJERFAN

All you can say with certainty is that whatever was on the coin dissolved in isopropyl alcohol; which is probably just as good a solvent for the plasticizer [octyl or nonyl phthalate] found in PVC as is acetone. Alcohols are polar solvents [after all they ARE derivatives of water] but are not very good solvents for some oils and greases. At least with rubbing alcohol formulated for topical use on the skin you are probably pretty sure that it is contaminant free.

Jdurg

<< <i>It just looks whizzed to me.

And is not PVC generally green ? >>



I think the color depends on the base metal. I know that I've had some silver coinage that was stored in a cheap PVC flip for a good decade or so that developed the same white 'haze' to it that this dime had. It almost looks like a tiny bit of frosting on the coin. I just noticed that as soon as the coin hit the alcohol, the white haze/frost completely dissapeared from it. I was actually pretty amazed at how well it turned out because some other PVC damaged coins that I've had were permanently damaged. (I.E. no matter how much alcohol/acetone it was soaking in, the haze wouldn't go away).

morgannut2

No PVC starts as a very light haze. As the copper in the metal bonds into a crystaline compound, it developes a greenish
relected light interferance "color" . At that point you are already losing metal from its original cubic closest packing molecular
order into a non sulfide organic compond on the surface of the coin. Ultimately the surface compond will block all light and seem dark greyish or "black". Pure acetone (from beuaty supply house-chemical wholesaler to doctors labs) is very good on early PVC damage control.

Jdurg

<< <i>No PVC starts as a very light haze. As the copper in the metal bonds into a crystaline compound, it developes a greenish
relected light interferance "color" . At that point you are already losing metal from its original cubic closest packing molecular
order into a non sulfide organic compond on the surface of the coin. Ultimately the surface compond will block all light and seem dark greyish or "black". Pure acetone (from beuaty supply house-chemical wholesaler to doctors labs) is very good on early PVC damage control. >>



Hmmm. Now I really wonder what that white haze was on the coin, and why the isopropanol was able to remove it almost immediately.

oreville

The white haze looks like the effect of long term entire surface condensation due to high humidity. But that is my opinion only.

I admit that i did not see the original PVC commentary so i did not comment on it.

morgannut2

Bajjerfan has it right: All we know for sure is it was soluable, and the apparent toning area on the right was not. I have seen coins with haze appear that were contaminated by the plasticizer of the flip, removed by dipping in acetone. This is a new one though. What else is in the isopropanol? Who knows.

Sphinx357

What is that mark on his temple that stayed there?

morgannut2

It was there before but not as noticable. The circularity suggests to me PVC pit area damaging the luster, intead of toning.

Jdurg

<< <i>Bajjerfan has it right: All we know for sure is it was soluable, and the apparent toning area on the right was not. I have seen coins with haze appear that were contaminated by the plasticizer of the flip, removed by dipping in acetone. This is a new one though. What else is in the isopropanol? Who knows. >>



The isopropanol should be 91% isopropyl alcohol and 9% water according to the bottle. I know you can also get 99% isopropanol pretty much anywhere. I'm now wondering if that would be just as effective as acetone, but easier to use since it's completely water soluble?

pharmer

I think it was Russ than mentioned a while back, acetone then 99% isopropyl as the final rinse. I didn't ask, but assumed it was because it will likely evaporate completely without residue.