How do you identify if an old plastic flip has PVC in it or not?

Good info. thanks everyone.

 

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Yes, you are right.
In my mind, I associated it with green as that's the color of the rocks/ore that contain copper.

 

Its called the Beilstein test. The green flame is from a copper halide (chlorine in this case) that forms.

Better Living Through Chemistry, I always say.

 

Instead of scratching your head simply purchase new holders that are PVC free. Carefully inspect your coins and take action on any that show PVC contamination. It would not hurt to give your gold, silver, and nickel clad coins a quick acetone bath.

 

Salt water is denser than tap water. Some things will sink in both, some things will float on both, and some things will sink through tap water but float on salt water.

If you've got to sort things with different densities, this makes a great shortcut -- find something that will let one thing sink and the other float, and then skim away what you do or don't want from the top.

Apparently there are a wide range of known-density liquids used for separating minerals. Some of them are surprisingly dense. Nothing comes close to mercury, though.

 

Hi Joshua,
I have always found that PVC flips felt 'greasy', unlike Saflips, if this helps.
J.T.

 

With the cheap cost of new flips that you know have no PVC, I'd throw all of them out and and buy new ones. Why waste time preforming "tests?"

 

Because copper doesn't "burn" green except in the presence of a halogen...Beilstein Test. See @Oldhoopster I didn't read to the end before I replied.

 

Did you know mara... weed seeds float in liquid nitrogen...just saying

 

Concerning PVC "contamination". From a chemical viewpoint I don't quite understand it. PVC is a rigid glass-like polymer when not plasticized. The addition of some oily chemicals (usually dioctylphthalate or DOP) disrupts the crystalline character and makes the chains "float" over each other and for the plastic to become flexible. Now DOP isn't such a bad actor, it shouldn't cause any deterioration of a metal surface by itself, so what causes the damage? It does leave a sticky film on the surface which could act as a solvent to let other chemicals dissolve and act on the surface. As to the PVC itself, over time it can decompose giving off HCl gas which would definitely hurt most metal surfaces. Any thoughts on this? I respect experience which says the flips do harm, I'm just wondering about the mechanism that leads to the harm.

 

Density/Buoyancy. PVC it is heavier than freshwater, so are non-pvc plastics, except if we were to add in displacement or surface area of the item in question. You can float concrete in the ocean, if it's large enough and has enough displacement.

the addition of the 2 tablespoons of salt to that 8 oz. of water ratio has it to where the less dense no-pvc containing plastics float, while the PVC doesn't. the variations in PVC density readings can be because the sample is flexible pvc vs. rigid, but flexible is ranged at (1.3-1.7g/cm3) depending on the mix now a days of the plastic.
in the old days though it was a lot of PVC in the mix. so in very many instances your samples density is going to be on the maximum side of the range, not the minimum. PET plastics are 1.3-1.4 density range.

The salinity of 2 tablespoons of salt in 8 oz of water is roughly 4x the salinity of seawater. for seawater's salinity and density it's more like a half tablespoon per a pint.

the water gets heavier with the addition of the dissolved salt and then one sinks, and the other floats. A gallon of saltwater weighs roughly 1/10th of a pound more than a gallon of freshwater because of the dissolved salt.

Anyways, in a lot of cases this works, The PVC is denser than the water and stays down, the non-pvc plastic material is lighter than the water density, so it's bouyant.

in fresh water nether would float as both are more dense than the density of the fresh water (0.99 at room temperature approx.)

used to be an old experiment to float an egg in a glass of water, dump in a bunch of salt. do it slowly also until it becomes neutrally buoyant, top with freshwater to drop it, top with saltwater to raise it, fool your friends that it's magic!

I did say "kind of" scientific. it's not all science really but it works.

And hey, I'm a bit of a nerd about stuff with my free time, 40 years ago and now. Why waste my time mixing stump remover and sugar when I can just go buy a model rocket engine at the store? ......Because its interesting to me.

 

I no longer have the references, but I recall reading years ago that the plasticers + water (humidity) can form HCl as a decomposition product. Higher temps will also increase the rate of plasticizer decomposition, so that's why the problem appears faster in areas like Florida and the southeast as opposed to northern parts of the country. I remember the references and chemical equations made sense at the time, but I'm relying on 15 year old memories and avoided organic chemistry courses like the plague when I was in college, so take that into consideration.

 

I have an old UNESCO "700 Science Experiments for Everyone" book that shows buoyancy with liquids available in any classroom -- mercury, carbon tetrachloride, water, and kerosene.

Ah, found it:



From 1956, when life was cheap, and so were hazardous chemicals...

 

Actually if the plasticizer decomposes, you get octyl alcohol and phthalic acid. The HCl would come from the PVC as it decomposes.

 

See if you can find a copy of "Eleven Blue Men"

 

Here's one, maybe:

https://www.sciencedirect.com/science/article/pii/S1658365514000880

So, it breaks down under heat, light, or mechanical stress. The breakdown produces HCl, which could just diffuse into the air -- but if it encounters that plasticizer, it can presumably break that down into octanol and phthalic acid, a liquid and a solid. And if there's moisture, it can just dissolve to form our old friend hydrochloric acid.

PVC flips:
1) are transparent, which means light can affect molecules anywhere throughout the plastic, not just on the outer surface;
2) are soft, making it easier for breakdown products to migrate from place to place;
3) bleed or bloom out liquid, which can dissolve those products and convey them to a coin's surface.

Okay, time to try again to climb back out of the chemistry rabbit-hole...

 

(Googles book)

Well, it looks like I'll bloody well have to now.

 

Good luck getting hands on a quantity of mercury. And if you do, keep it away from your coins. I used to have access to approximately 4oz of it. Used for calibrating pressure/vacuum gauges to national standards. Manometers and such.