Will Specific Gravity Test harm a coin

I've read through all of the cleaning threads I could find as well as the specific gravity test threads, but I can't seem to find an answer.

Will performing a specific gravity test on a coin damage it? Yes, the coin will be submerged in water for a second or two, but it the coin is not scrubbed dry, will it be ok?

Some people are saying never let your coins near water. Others are saying that distilled water only will not damage a coin, especially if it's blotted (and not rubbed or scrubbed dry).

Thoughts?

 

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Distilled water is fine. Just make sure to pat (not rub) the coin dry.

 

Even tap water is not harmful to coins as long as it is not allowed to dry on the coin. Blot them dry.

 

Water should be OK.

 

How are you doing the specific gravity test?

 

Yes, why test the coin like this?

 

I've bought a large group of raw coins and a few of them were in cardboard flips marked "not real" but a bunch were loose. I've weighed them (my scale is accurate to 0.01g) and they fall into the proper range, but before I send any of them off to be graded, I wanted to do some additional tests.

For instance, with the Lincoln cents, there are some key dates. The size is right, the weight is right, and they are non-magnetic. I want to do one final test before spending the money of grading.

For the test, I am following one I say on YT. I'll weigh the coin, then zero my scale with a cup of water, then "float" the coin and calculate using that weight.

I've never done it before, so though I'd ask here about the affect of water.

 

Post pictures of both sides of the coins in questions before spending any money to grade them.

 

Uh...yeah, grading is an expensive proposition and usually recommended for coins in the $100 or more range. Plus, there are lots of fakes out there and they are usually on the key date coins. There are many (not including myself) experienced coin collectors here, including dealers and I would REALLY recommend posting pictures here to get an informed opinion.

 

Its the "floating the coin" that determines accuracy, since most coins won't actually float, you have to devise a free hanging (very thin strand, that has minimal weight and neutral bouyancy ) or it will affect specific gravity measurement. Jim

 

Can we see photos of the key dates? We might be able to help so you don't have to perform such tests.

 

Someone here posted a good hint. When you put the container with water on the balance, before you zero it, put the tweezers you are going to hold it with into the water at about the same depth you are going to while they are holding the coin.

 

Thanks everyone.... I'll upload a few here instead of starting a new thread. First, I'll apologize if the photos aren't up to snuff. I'm still working on my technique, especially with darker coins.

Of course, these are the best of the cents, which is why I'm curious. Of the following, the RD 1909 is definitely bad. I'm almost certain the 1909 BN is good. I'd say it's a VF-20 or 25. Maybe a VF-30 on a good day. The 1955 is a question for me.

I have one more that is over at my neighbor's house and he's not home for me to grab it.

In this order are:
1955 DDO (I believe it's a cast fake)
1909-S VDB (Also a cast fake)
1909-S VBD (All indications are it's real)

 

For the test, I was going to experiment with fishing line since it has almost no weight, it's water resistant, so it won't soak it the water, and I don't trust myself with tweezers on a coin!

 

Actually, you can use any liquid which is noncorrosive and has a density of less than the coin to do specific gravity. Don't use drain cleaner or mercury! But water is most common because it's readily available and cheap. You do have to know the density of the liquid. Water is easy because it's 1.

The denser the liquid (as long as it is less dense than the coin), the more accurate the specific gravity determination. This is because a denser liquid gives more "lift" to the coin, so the difference between the coin's weight in air and liquid is greater. Some labs use carbon tetrachloride or perfluoromethyldecalin because they are dense and non-reactive with coinage metals, minerals, and gemstones. Some minerals dissolve in water!

I've used water and perfluoromethyldecalin in the past. These days, I have a friend with a XRF analyzer which reads-out the metal composition.

Cal

 

The Mint Mark of the first S-VDB definitely looks off. I think it is safe to say that one is altered. The 1955 DDO also looks suspicious-- it could be the photos, but the "flatness" of the surfaces bothers me. The second S-VDB looks OK to me at first glance.

 

I would first check the weight and diameters, and see if they are within tolerances.

 

Thin fishing line is OK if it doesn't float easily. Jim

 

I turned in my gallon of carbon tet to a chem department for safe disposal decades ago. I've regretted it from time to time since.

I looked up perfluoromethyldecalin -- density 1.92. "Hmm," I thought to myself, "that could be handy for all sorts of things! Wonder how much it costs..."

Looks like about $100 per fluid ounce. Perhaps not.

I'll probably waste some time now looking for affordable dense liquids. Mercury is bad, as you say, and too dense for anything but gold or platinum anyhow. Bromine is easy to make, but terrible for metal objects (and their owners). Hmm. Solutions of heavy stuff? Hmm...

 

the doubled LIBERTY on the 1955 just looks plain wrong comparing it to a real one.
Go compare it to the ones on aliexpress for $2.50 each.