In a message dated 2006/11/14, JohnJan@........ writes:

> At 11:36 PM 11/12/2006, you wrote:
> >I have heard quarters are mostly copper ?
> 
> The dime, quarter, and half dollar are all 91.6% copper and the rest nickel. 
>  See:
> http://www.usmint.gov/about_the_mint/index.cfm?action=coin_specifications

Hi John,

       It is the much higher electrical resistivity which kills this 
application - apart from the susceptability and any implications of defacing the 
coinage. The damping effect on our 2p coins is far less that on pure Cu sheet.

> Although Cu is slightly repelled by a magnet, the Cu Ni alloy will be 
> slightly attracted. However, this attraction might be small enough to ignore.

       Not with UK 'copper' Coins. US coins are 8.3% Nickel

> http://prola.aps.org/abstract/PR/v38/i4/p828_1
> The magnetic susceptibility of alloys of copper 
> and nickel in proportions ranging from 0.1 to 70 
> percent nickel have been studied. X-ray 
> photographs of the alloys show that they are a 
> homogeneous mixture of the copper and nickel 
> crystals. Although copper is only weakly 
> diamagnetic it requires 0.8 or 0.9 percent nickel 
> to neutralize this diamagnetic effect and 56 
> percent nickel is required before the alloy shows 
> ferromagnetic properties at ordinary 
> temperatures. 

> McMaster Carr  charges 
> $20.84 for a 1/16" strip of Cu, 1 inch wide by 6 inches long.

       This is an idiotic price. It is even more expensive than 
www.ksmetals.com!

> Maybe flattening a piece of Cu pipe is still the best way to go. Have to be 
> sure it's copper and not brass pipe.  See: 
> http://www.copper.org/applications/plumbing/techref/tpf_stds/tube_pipe_stds.h
> tm

       I suspect that you may not be approaching the right sales outlets. Go 
to a plumbing firm and ask if they have any odd lengths of large diameter 
tube? How about looking up metal suppliers / stockists / non ferrous? Scrap 
dealers may have Cu water cylinders.

       If Cu is so difficult to get, you can use soft AlSi sheet, but it is a 
bit paramagnetic. Pure Al may be difficult to find.
       
       Regards,

       Chris Chapman
In a me=
ssage dated 2006/11/14, JohnJan@........ writes:



At 11:36 PM 11/12/2006, you wro=
te:

>I have heard quarters are mostly copper ?



The dime, quarter, and half dollar are all 91.6% copper and the rest nickel.=
  See:

http://www.usmint.gov/about_the_mint/index.cfm?action=3Dcoin_specifications<=
/FONT>=




Hi John,



       It is the much higher electrical resist=
ivity which kills this application - apart from the susceptability and any i=
mplications of defacing the coinage. The damping effect on our 2p coins is f=
ar less that on pure Cu sheet.



Although Cu is slightly repell=
ed by a magnet, the Cu Ni alloy will be slightly attracted. However, this at=
traction might be small enough to ignore.




       Not with UK 'copper' Coins. US coins a=
re 8.3% Nickel



http://prola.aps.org/abstract/P=
R/v38/i4/p828_1

The magnetic susceptibility of alloys of copper 

and nickel in proportions ranging from 0.1 to 70 

percent nickel have been studied. X-ray 

photographs of the alloys show that they are a 

homogeneous mixture of the copper and nickel 

crystals. Although copper is only weakly 

diamagnetic it requires 0.8 or 0.9 percent nickel 

to neutralize this diamagnetic effect and 56 

percent nickel is required before the alloy shows 

ferromagnetic properties at ordinary 

temperatures. 




McMaster Carr <http://www.mc=
master.com/> charges 

$20.84 for a 1/16" strip of Cu, 1 inch wide by 6 inches long.



       This is an idiotic price. It is even m=
ore expensive than www.ksmetals.com!



Maybe flattening a piece of Cu=20=
pipe is still the best way to go. Have to be sure it's copper and not brass=20=
pipe.  See: 

http://www.copper.org/applications/plumbing/techref/tpf_stds/tube_pipe_stds.=
htm




       I suspect that you may not be approachi=
ng the right sales outlets. Go to a plumbing firm and ask if they have any o=
dd lengths of large diameter tube? How about looking up metal suppliers / st=
ockists / non ferrous? Scrap dealers may have Cu water cylinders.



       If Cu is so difficult to get, you can u=
se soft AlSi sheet, but it is a bit paramagnetic. Pure Al may be difficult t=
o find.

       

       Regards,



       Chris Chapman