toning related question on lubricants used at the mint

lasvegasteddy

hi,
just a beginner's question on reguards to toning here.does anyone know for fact what type of lubricant is used on dies or planchets for minting?how important would use of exact lubricant used before storage in an envelope for toning after acetoning circulation questionable crud off before "enviromental damage results.but curious about the lubricants as i do see alot of "struck thru grease"attributation as well as a dry minting with no lubricants seems harsh for life.thanks in advance on this topic from those pro's on here as i am usally left speechless by the knowledge of others

cladking

Great questions but little is known about it and it changes pretty frequently.

Curiously I just ran into a horrid grease strike '92 quarter in a mint set the other
day. Curiously it had some small patches of grease adhering to it which might
just help answer this question someday.

lasvegasteddy

yeah i know someone professed to a degree in chemistry so i figuire someone of that calibur could comment on the union of silver and whatever is on the surface at time of minting and the importance of this composition in the toning process...i am currently to store my peace dollar collection in manilla envelopes after acetone light crud removal and wondering if i should re-coat them with what might be found at the mint on planchets before minting...stupid beginner stuff i know

MrSpud

No doubt anything on the surface of the coin would effect toning. Just a bit of finger oil or other oily substance seems to lessen the tendency for that spot to tone evenly. The methods to clean/rinse the planchets are also supposed to affect toning and differences in how the planchets were washed is often cited as a factor on why Peace Dollars don't tone the same as Morgans. I also noticed during some toning experiments that the finish of the coin makes a big difference on how easy it is to get a nice toning layer to develop on a coin. A smoother finish toned easier and more evenly and vibrantly whereas the more "matte" the finish was the harder it was to get them to tone at all and when they did tone the toning wasn't as even. I'm just talking about the normal differences in finishes of business strikes here, as in leaning towards proof like vs. leaning towards a more matte-like appearance.

CaptHenway

<< <i>hi,
just a beginner's question on reguards to toning here.does anyone know for fact what type of lubricant is used on dies or planchets for minting?how important would use of exact lubricant used before storage in an envelope for toning after acetoning circulation questionable crud off before "enviromental damage results.but curious about the lubricants as i do see alot of "struck thru grease"attributation as well as a dry minting with no lubricants seems harsh for life.thanks in advance on this topic from those pro's on here as i am usally left speechless by the knowledge of others >>



In the Summer of 1981, I was taking one group of ANA Summer Seminar students through the Denver Mint and we ended up down in the basement where they were packaging the D-Mint half of that year's Mint Sets. Being a nosy sort, I wandered into an adjacent room and found a large stainless steel tub with a lid on it, a small hand-cranked cement mixer and several 100-pound sacks of dried, crushed corncobs.

I asked our Mint employee guide what they were for, and he said that up on the production floor they sprayed a light machine oil on the planchets to make them pass through the feeding mechanism better. However, if left on the coins it discolored them, and so they cleaned the Mint Set coins before packaging them. The tub was full of liquid freon, and they would dump a bag of coins in a wire basket and shake it up and down like we used to do with the french fries at McDonalds. Then, to get the liquid freon off the coins, the coins in the basket were dumped in the cement mixer along with a few scoops of the crushed corncob and tumbled.

Look at Mint sets from the mid-1970s before they started doing this and see how the copper-nickel is discolored. Then look at the sets leading up to 1981 and see how untoned, but horribly bagmarked, they are.

Tom DeLorey

lasvegasteddy

hey tom,
very interesting writings there...

Conder101

<< <i>The tub was full of liquid freon, and they would dump a bag of coins in a wire basket and shake it up and down like we used to do with the french fries at McDonalds. Then, to get the liquid freon off the coins, the coins in the basket were dumped in the cement mixer along with a few scoops of the crushed corncob and tumbled. >>


I'm sure you saw that and the explanation is correct as to what it was for, but it wasn't liquid Freon. Depending on the type, Freon boils at -49 to -20 degrees Farenheit and at room temperature will only remain a liquid at pressure (Several atmospheres). If you opened a "tub" of liquid Freon the entire tub would flash over to vapor in a matter of seconds killing anyone in the room not wearing an oxygen mask (and possibly still freezing them.) and potentially causing damage to the room itself from the explosive expansion of the gas. And with something that volitile, needing crushed corncobs to dry them would not be a concern.

Most likely the tub contained a simple organic solvent like xylene or something similar. It removes the oils and vaporizes fairly quickly (Seconds to a minute) and the corncobs are used to absorb the solvent so that it it doesn't just evaporate and still leave oil residue on the coin.

I find that people who don't know the difference will often call any rapidly evaporating organic solvent "Liquid Freon".

PerryHall

Considering what the mint is now charging for the proof AGE's, I assumed they were using K-Y for the lubricant.

Kip

<< <i>Considering what the mint is now charging for the proof AGE's, I assumed they were using K-Y for the lubricant. >>




The new Mint director is Ben Dover

mgoodm3

Every time I see the thread title, it creeps me out.

carl

I'm not sure of what your question exactly is concerning, however, it appears your wondering what type of lubricants are used at the US Mint for coining coins. I would suggest you contact the US Mint to see if they would release that information. There may be different lubrications for different types of dies and/or metals. In industry it is commonly known that some lubrications could react with certain materials and eventually create damage. Some lubrications have ingrediants that cause faster evaporation. As I noted it would be best to contact the Mint for exact materials used.
If on the other hand your question is how to create toning on a coin, there are numerous posts on this forum lately on that subject.
If on the other hand you would like to stop any toning that is simple. Seal the coin from air.

Longacre

Interesting discussion.