Large flatbutton question

[gtoast99]

Hey all! I have two quick questions about this flatbutton I pulled today.

First of all, what's it made of?? I'd expect a copper or copper alloy button this big to ring up with a nice high tone, but it's more like nickel/pulltab. Which confused me a bit. Where is tombac on the conductivity scale?

Question two is age. I know without markings it's tough to say for sure. But would it be wrong to suppose this button is colonial or just post colonial, say 1750-1800 time frame? Or might it be later? Earlier? I rarely see them this big is all.

Any help would be appreciated!!

 

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[steelheadwill]

Tombacs read low on my machine, similar to a nickel. (Dig em all)
I just read that the composition of 'Tombac' metal is 88% copper, 12% zinc,
with that much copper, I'd think they'd ring higher
it is certainly durable, 200 year old buttons look like new
I can't help much with a date range, they were used for a long period of time. good sign of an old site

 

[gtoast99]

Thanks, I was hoping someone would chime in with where tombac is on the conductivity scale, now I'm pretty sure that's what I have. I'd have thought higher with that much copper too, but then nickels are 75% copper and sound low. I know just a little bit of mixed metal can change the properties quite a bit.

Thanks for the help!

 

[CRUSADER]

1780-1830 Tombac, as stated

 

[Swartzie]

Tombacs read low on my machine, similar to a nickel. (Dig em all)
I just read that the composition of 'Tombac' metal is 88% copper, 12% zinc,
with that much copper, I'd think they'd ring higher
it is certainly durable, 200 year old buttons look like new
I can't help much with a date range, they were used for a long period of time. good sign of an old site

Yeah, tombacs have hit low for me too. Just a little above foil on the smaller ones.
-Swartzie