Electro plate prints.

[richardphat]

Yup, mine were pretty much guaranteed to be copper before 1984, say 1980 for safe. But recently the whole canadian shift toward the no more pennies solution, since it cost more to produce them than what they are worth.
Pretty sure US or UK have pure commercial grade, just need to know the year before they start using alloy.

Alternatively, those copper pipe from the hardware store could work, all copper pipe must be above 99.9% according to the copper developpment and association.
http://www.copper.org/applications/p...pipe_stds.html

[Feign]

Pure copper pennies are getting harder to find, yes. I think current pennies are made with a copper-nickel alloy but it still works fine as an anode. Often you'll find pennies in circulation that look like they've been recovered from an ancient shipwreck, but are only a few years old by their mint date. This was probably the cause.

Another trick is plumbing and home care stores have a product called ZEP Root Kill, which is pure Copper Sulfate Pentahydrate. Other septic tank root killing treatments are also very likely to have high concentrations of copper sulfate. I learned about it from this Youtube video, but apparently it's a fairly well-established trick with folks who make their own ammo.

[Mjolinor]

UK has always used alloy, it was bronze but is now copper plated steel.

The best stuff to use is either copper pipe or copper wire.

[Mjolinor]

Hmm, that brings back memories. We used to lust over Aus pennies. The shops here used to take them because they were the same as ours but had a kangaroo on the back. I suppose they weren't really legal tender but no one seemed to really bother. I think I have some somewhere in the back of a cupboard.

Yes teh copper will dissolve, as will the tin. You are better off using a bit of pipe or wire.

[LambdaFF]

I looked into it a few months ago. For the initial bath, sulfuric acid and copper powder won't cost you more than 20€ for a few liters. Normally with a plumbing tube for sacrificial material you shouldn't need to regenerate the bath.