Coins in fountains

Suzanne Hargrove <objcons [at] slam__org> writes

>We have a functioning marble fountain that people regularly throw
>coins in. As you may know U.S. pennies are no longer solid copper
>and corrode in the water.  Other than removing the coins more
>frequently (which is a drain on staff time).  Does anyone have ideas
>regarding corrosion prevention and removal of corrosion products
>from the coins.  To date the marble of the fountain where coins
>would lie is kept dry so there is not a problem of staining the
>stone, though I would be worried about any chemical water additives
>as the stone is occasionally splashed.  The problem we are having is
>that the bank does not want to accept our coins as the corroded ones
>damage their counting machines.

Apart from the fact that I do not understand how a functioning
marble fountain could be dry, I have the following proposal for a
solution to the problem.

I would propose to let the bottom of the basin be filled with an
inert liquid, such as kerosene or a silicone oil of low viscosity,
which would be transparent and immiscible with water. The greater
part of the basin would be filled with water as usual. If the water
in the basin is usually circulated to create a fountain, the suction
pipe would have to be elevated above the layer of inert liquid.
There may be local environmental issues deciding upon the kind of
liquid you could use.

George Brock-Nannestad
Preservation Tactics
Denmark


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                  Conservation DistList Instance 15:75
                   Distributed: Tuesday, May 7, 2002
                       Message Id: cdl-15-75-004
                                  ***