Dipping silver coins - removing PVC - HELP!!!

[macrocoin]

I hear a lot about dipping.

I have also heard of folks mentioning NCS dipping coins as part of restoration.

Exactly what are they being dipped in?

 

I had a Washington quarter done by NCS and I assumed they dipped the coin in something to lift some black spots which were appearing on both sides of the coin. I am very curious to know exactly how a coin is 'restored'.

 

I have a few morgans...two in specific...that need some help.

They are both 1921 common date morgans, but both AU and have nice details.

I want to preserve them as best I can, but I cant justify NCS for them since they arent worth much more than spot.

 

One coin clearly has PVC on it...the other has a thin layer of black...not toned so much...looks more like soot. Its not attractive, and I dont think it will get better over time.

 

What products are available to me which might help lift off whatever it is that is clinging to both? Thanks in advance for advice.

[Brotherman]

Brillo-pad?

 

I don't know, probably acetone - but one of the smart guys will be along soon

 

Hays

[macrocoin]

Brillo-pad?

 

I don't know, probably acetone - but one of the smart guys will be along soon

 

Hays

 

I was actually reading that acetone can damage the coin.

I want to do whatever is least abrasive and damaging.

The idea here is to restore and conserve.

I have no desire to mask a deficiency, I mostly want to nuetralize the PVC damage on the one coin.

 

Another question I have is, after a coin is dipped is it wiped off with something or is it just air dried? I would think wiping with a cloth would leave hairlines. I had a DCAM proof restored and I cant imagine it was wiped with anything, but I am not the conservation expert either. I really wish i knew more about this process.

[ldhair]

Acetone can not harm your coin. It is not an acid.

It will remove only organics. It's only going to remove the gunk from the surface of the coin. The surface under the gunk may already have damage. It's a gamble.

Not all coins come out of acetone looking better but it puts a stop to future damage from the PVC.

As far as the dark coin goes, not sure you can help it much.

An acid dip will help it look white but most dipped AU coins look like [embarrassing lack of self control].

[TomB]

Acetone, aside from being incredibly flammable, able to carry otherwise non-permeable substances through your skin and toxic if inhaled in excess is not a magic solution. It will remove PVC and other organics quite nicely but will not harm the metal. As Larry has already pointed out, however, if there is damage under the PVC then acetone will expose that damage to the environment. If you use acetone there is no need to wipe once the coin has been cleaned of contaminants because acetone is extremely volatile and will evaporate in seconds to leave behind on the surface of the coin any gunk that you have not previously washed away.

[macrocoin]

How long should I place the PVC damaged coin in acetone for?

Should I try to pat off the residue with a cloth afterwards or will it just disolve?

[TomB]

If you are going to attempt to use acetone please use it in a well-ventilated area that is scrupulously clean of sparks or other sources of ignition!

 

I've poured 2-5 milliliters of acetone in a clean dish over a coin and simply swirled in a gentle manner for a few seconds. I've then dumped the acetone into a larger bowl that already contains water and rinsed the coin again in a similar manner, again disposing of the acetone into a bowl with water. Once you are confident that the gunk has come off you can stop rinsing. Typically, this will take one or two rinses.

 

Acetone and water are infinitely miscible.

[ldhair]

I use a shot glass the right size to keep the face of the coin from touching the glass.

Fill with acetone and cover with a small piece of paper. Change out the acetone after 30 minutes or so and soak for another 30 minutes.

At this point I do a final pour rinse. If any PVC is left on the coin , you don't want to see the surface of the coin under it.