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Just been going through some old coin gaffs and found the 2p shell from a CU with a normal 10p firmly wedged inside it. The 10p won't come out whatever I try so, as a last resort, I'm going to apply some O-level science and try to use heat/cold to solve the problem with the vague hope that the shell or coin will expand/shrink enough to get them apart. Can any scientific types suggest whether extreme heat or extreme cold is likely to work best? Thanks!

Heat causes metal to expand.

Jean Eugene Roberts wrote:Heat causes metal to expand.

True, but the 2p and 10p are both metal. The question is will one expand (or in extreme cold shrink) faster than the other making it possible to get them apart. If the 10p expands slightly quicker than the 2p then heat will make the problem worse rather than better.

The copper 2p should expand more than a stainless steel 10p due to thermal expansion when subjected to heat, if memory serves and theory is correct.

Is the 2p Shimmed/Attractive?

If so, have you tried supergluing the 10 to a flat surface, and using a large Neo, to see if that would pull the shell away?

Grimshaw wrote:The copper 2p should expand more than a stainless steel 10p due to thermal expansion when subjected to heat, if memory serves and theory is correct.

OK - I'll go and try it and then report back...

magicrob wrote:Is the 2p Shimmed/Attractive?

If so, have you tried supergluing the 10 to a flat surface, and using a large Neo, to see if that would pull the shell away?

The head of a "clout" nail should serve well as a flat surface.

Go with cold, but the superglue and the magnet are a far better suggestion.

well if you dont mind losing the 10p, here is my solution:

1) buy kiln
2) pre-heat to 1150 C
3) insert coin+shell
4) wait for a bit
5) pour out 10p
6) leave shell to cool

at this temperature, the shell should stay intact, but the 10p should melt (assuming wikipedia has correct data).

for kiln buying advice please go to: http://www.bigceramicstore.com/Informat ... a_kiln.htm

an elegant solution I'm sure you will all agree

magicarp wrote:well if you dont mind losing the 10p, here is my solution:

1) buy kiln
2) pre-heat to 1150 C
3) insert coin+shell
4) wait for a bit
5) pour out 10p
6) leave shell to cool

at this temperature, the shell should stay intact, but the 10p should melt (assuming wikipedia has correct data).

for kiln buying advice please go to: http://www.bigceramicstore.com/Informat ... a_kiln.htm" target="_blank

an elegant solution I'm sure you will all agree

Aren't kilns a bit on the pricey-side, though?

magicarp wrote:well if you dont mind losing the 10p, here is my solution:

1) buy kiln
2) pre-heat to 1150 C
3) insert coin+shell
4) wait for a bit
5) pour out 10p
6) leave shell to cool

at this temperature, the shell should stay intact, but the 10p should melt (assuming wikipedia has correct data).

for kiln buying advice please go to: http://www.bigceramicstore.com/Informat ... a_kiln.htm" target="_blank

an elegant solution I'm sure you will all agree

Might have to try this - nothing else has worked!

obviously buying a new shell would be cheaper, but that would be admitting defeat!
#rob: yeah kilns are a bit pricey, but I've got two words for you: POTTERY MAGIC. I can feel teh future of magic shifting as I type. Think of the possilities open to a magician with the ability to make their own, customised, clay pots!