How hot are coins immediately after minting

Discussion in 'Coin Chat' started by ron_c, Dec 12, 2014.

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  1. coleguy

    coleguy Coin Collector

    Air temp is calculated using radiative dynamics. Skin is the same as metal in this regard. This is why we burn. Not to mention, if I had my shower set to deliver a measly 110 degree water, it would be on average about 5-10 degrees colder than the median air temp 9 months of the year where I live. And that isn't a dry heat as many non desert dwellers seem to believe.
     
    coleguy, Dec 13, 2014
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  3. ToughCOINS

    ToughCOINS Dealer Member Moderator

    Insufficient time-of-contact between dies and coin take place for significant heat transfer between the two. The dies and the press are incredibly large heat sinks, and absorb much more of the heat associated with each strike than do most of the planchets, until, of course, the day has been long, and the tooling and press have heated up a lot.

    The heat-treatment of the blanks does not take place immediately before striking. Typically, the planchets are annealed long before they even approach the presses.

    While the coins will indeed be warmer when ejected from the press, the dings you see on coins are from concentrated stress, imparted by edges and especially by reeding, whether impacted immediately after striking or long afterward.
     
    ToughCOINS, Dec 13, 2014
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  4. cladking

    cladking Coin Collector

    I often suspect that a lot of the best strikes come from unusually warm planchets. There is probably a fairly wide range of temperatures that planchets can be from below freezing to as much as about 100 degrees. Most will be near room temperature but the range could be significant.

    I've always wondered what conditions have to exist for a perfect Gem to be minted. Of course a few more of these are produced than just what leaves the mint. These coins can be virtually non-existent for some dates.
     
    cladking, Dec 13, 2014
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  5. Spenco777

    Spenco777 New Member

    I once put a lot of sunscreen in a box and lit the stuff inside to see what would happen I burned all the hair off my leg and arm
     
    Spenco777, Dec 13, 2014
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  6. Vegas Vic

    Vegas Vic Undermedicated psychiatric patient

    This taught me a lot of things I didn't fully understand. Thanks so much for posting it.
     
    Vegas Vic, Dec 13, 2014
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  7. JPeace$

    JPeace$ Coinaholic

    Cool video. Love the music! I thought I was watching an old horror movie at times...lol.
     
    JPeace$, Dec 14, 2014
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  8. ToughCOINS

    ToughCOINS Dealer Member Moderator


    An interesting question.

    Bear in mind that, while the very best strikes may well be the result of recently annealed planchets, those are the very same coins that would likely take on the most marks after strike, so I wouldn't necessarily correlate the warmest planchets fed into the press with the highest quality coins to reach collectors hands.
     
    ToughCOINS, Dec 14, 2014
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  9. Searcher64

    Searcher64 Member

    When you talk about getting burned by metal. I was a welder for about 25+ years. I spot welded, brazed welded, mig welded, stick welded, and cut steel with a torch, and plasma cut metals too. So, getting burned and shot with hot metals of all kinds does hurt and leave many scars. Great job. Have been around die stamping presses too in the auto industry.
     
    Searcher64, Dec 14, 2014
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  10. Conder101

    Conder101 Numismatist

    The planchets have to be washed and burnished after annealing, and they spend time sitting in bins and hoppers waiting to be fed into the press so they would be at room temperature by the time they get to the coining chamber.
     
    Conder101, Dec 15, 2014
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  11. 4$tella

    4$tella New Member

    Agreed! I really enjoyed this video. Thanks for sharing!
     
    Last edited: Dec 19, 2014
    4$tella, Dec 19, 2014
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  12. Weston

    Weston Well-Known Member

    I am certainly no expert in this field; however, from a physics standpoint, an increase in pressure while maintaining the same volume will increase the temperature. A common example of this is ice skating. Increasing the pressure(under the blades of the skate) increase the temperature of the ice, causing it to melt in the spot you are standing/skating allowing you to glide along.

    Sound right?
     
    Weston, Dec 20, 2014
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