What should I do with this IHC?

I would think that PVC contacts the high points. Corrosion often starts in the low points.

 

Log in or Sign up to hide this ad.

This is absolutely WRONG!

PVC is not verdigris. Verdigris is a mixture of copper salts among which a high proportion is copper acetate, but also copper sulfate and copper chloride are present, among others. PVC is polyvinylchloride, which is a repeating polymer of C(2)H(3)Cl. These are absolutely and without question different compounds.

 

Is this a acetone product??

 

What should I do with this IHC?

Toss it into the junk box

 

I agree with Tom B. hya:
I've used acetone to remove PVC and other grime. I've used Verdi-gone and it removes verdigris. Unless the colors are off, this looks like it would benefit from a good soak in high grade acetone, with a pre-soak in distilled water, and a few exchange baths in each.

It won't hurt the coin.

If it doesn't come off with acetone, it's verdigris and will respond to Verdi-gone. A very usefull and well tested product. Read the instructions and go from there.

Bruce

 

Ok,PVC releases chloride,it is chloride that reacts to the copper to create verdigris.It takes chloride and its chemical reaction to create verdigris.PVC starts as a clear liquid,as it reacts to the copper in a cent it turns green.essentially without PVC verdigris does not exist.Silver contains little to no copper so it does not turn into verdigris.unless copper is present.

So PVC=verdigris on copper.

Some copper was stored in PVC at one time,and chloride from the PVC was released onto the coin.later the coin was put into an album,it still reacted to the copper and became a dry verdigris.

there are two types of verdigris dry & wet.

the chloride will come off with acetone,or most of it,because it has not "bonded" to the coin.but the 2nd stage of the PVC damage verdigris is chemically bonded tighter than acetone,that is why it will not come off.

 

That will come as a shock to those who find ancient coins with verdigris that never have seen time in a PVC holder or environment. PVC under normal conditions ( STP) is a hard chemical resistant plastic that typically would do no harm to coins. BUT when acidic plasticizers ( as much as 35%) are added to PVC to make it clearer and flexible, these can migrate from plasticized PVC flips and the acidic components in the present of moisture can begin the verdigris process.

PVC is not verdigris.

Jim

 

Personally, I am very satisfied with Thad's Verdigone as a safe way of trying to remove verdigris. I use the word trying, as some deposits are impossible to remove without physical force, which I do not recommend. Also, very often you will dislike what is UNDER the verdigris more than the verdigris itself. Search on Verdigone, and you will find several threads, including this one of mine.


http://www.cointalk.com/t47318/?highlight=verdigone

I do not , nor have I ever had a financial interest in this product. Even a beginner can use it safely IMO.

Jim

 

Chlorine creates this process, PVC contains the key element,chlorine.

please feel free to look it up.the internet is a very large information highway,if you cant find it I will be more than happy to direct you to the answers you need.

 

essentially without PVC verdigris does not exist.

This statement sets me back, reeling on my heels.

Perplexed look.

 

First off...

There's so much misinformation and folklore surrounding verdigris it just amazes me. I really can't wait to finish my book to teach people the facts about verdigris. In the mean time, I recommend reading the chemical composition definition of verdigris that I've posted on wikipedia (from my book):

http://en.wikipedia.org/wiki/Verdigris

This coin HAS mixed verdigris. Some of the light to moderate. may be removed, but the heavy verdigris probably cannot be conserved without: a) chemical surface damage b) leaving behind obviously cleaned surfaces below the verdigris c) surface copper removal (by the verdigris). What you find under the heavy verdigris will most likely not be pleasing. The thickness is such that a lot of copper has been pulled from the surface.

Any verdigris conservation project should ALWAYS start by following what I call the "Polarity Ladder". At minimum, this will prepare the surface for more advanced conservation techniques. Soak the coin in the following solvents, in order, for an hour or two (each side if affected):

1) deionized (or distilled) water
2) acetone
3) xylene

If no progress is made, reverse the order, go back to acetone and then water.

If these steps do not satisfy you, it's time to make a decision on trying more advanced techniques.

 

That would be a complete waste IMO. Verdigris salts mostly are insoluble in oil. Coin Care is nothing more than napthenic mineral oil with a citrus odorant.

 

ancient coins may not apply as directly to PVC. since in 1832 PVC has been in use. the same basic physical science applies to what we see the most of.

we were referring to more of a modern coin collection.to the basic collector it is easier and less complicated.because PVC is what creates the verdigris.
without the PVC,the likeliness of verdigris is almost not likely at all.

ancient coinage is more of a natural effect with chloride,copper carbonate or acetic acid.

 

the mineral oil could loosen the bond between the stable copper of the coin and the verdigris,and the PH from the citris would help neutralize the acidic salts,by lowering the PH in the bond.

I have not tried it,so I do not know the outcome.in theory it is a possibility.

 

If PVC released chlorides as you describe, PVC pipes could not be used to carry water and even harsh chemical sewage, as it would breakdown. This does not happen with the opaque hard plastic pvc pipes. Now for flexibility and transparency, plasticizers such as phthalates are added to allow the PVC molecules to slide over each other. This is the substance that can leach out of plasticized PVC, and produces the "vinyl shower curtain" smell. In very old PVC coin flips, the plasticizers are mainly gone, and the plastic becomes brittle, and would have very low probability of initiating verdigris.

Milk containers and other plastic containers used to have high levels of plasticizers, until medical concerns of leaching developed which led to most being reformulated .

Thank you for the offer of help.

 

That's actually almost correct. Verdigris is NOT "PVC on copper". Here's a quick summary of how PVC damages:

1) The plasticizer breaks-down and the plastic holder "melts" on the coin surface
2) The decomposition product hydrochloric acid is formed and it attacks the surface
3) Metallic chlorides are formed

The interesting thing about PVC corrosion is that it can occur in the absence of water and air.

 

That is completely and utterly incorrect. There's only TWO components necessary to begin the verdigris formation process: AIR AND WATER

I'm considering sending you a free copy of book when it's finished. :desk:

 

Have you ever tested your tap water? we create filters to remove chlorine.
something that is used in PVC.there are multiple levels of PVC.Placticisers do not contain chlorine,it is that chlorine that thats reacts with copper that creates verdigris,it is "cut & dry"

This definition,shows everything you will need.

Polyvinyl chloride, (IUPAC Poly(chloroethanediyl)) commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups (ethenyls) having one of their hydrogens replaced with a chloride group. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene.[3] PVC is widely used in construction because it is cheap, durable, and easy to assemble. PVC production is expected to exceed 40 million tons by 2016.[4] It can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is used in clothing and upholstery, and to make flexible hoses and tubing, flooring, to roofing membranes, and electrical cable insulation. It is also commonly used in figurines and in inflatable products such as waterbeds, pool toys, and inflatable structures

just a FYI I worked with All of the items in the definition.from creating them from raw material,to installing them.and I dont drink tap water.because of it.

 

OK, I'm not going to fight with you. How old are you? ....just curious.

Once again, completely incorrect statements you've made there. With inorganic, ionic bonds responsible for holding the verdigris to the surface, there's ZERO chance of an organic solvent "loosening" the bond. Copper salts are INSOLUBLE in organic solvents. I don't need to defend the science here, you need to educate yourself.

Oil has NO pH! The citrus odorant is NOT going to have the slightest effect even it was at an outrageous concentration. Products like this are normally formulated with odorant levels < 0.1%.

 

ok.