Brass or copper???

[Cornish JackParticipant @cornishjack]

[Cornish JackParticipant @cornishjack]

G'day all.

Having a rummage in the shed and found a large-ish sheet of metal with a paper, hand-written label indicating it's copper. It looks much more like brass – is there any simple way of distinguishing the two, please?

TIA

Rgds

Bill

[BazyleParticipant @bazyle]

If it didn't have a label would you be in any doubt? Did you get it at a boot sale from someone who didn't know the difference?
Brass will be more reactive to acid and if polished and etched with vinegar is likely to show a grain structure.
Is it a bronze which is more likely to be confused with copper by the original labeller? I have bronze door handles which are aged to a copperlike brown but look brasslike where the acid on my hands has 'cleaned' the tarnish.

[Cornish JackParticipant @cornishjack]

Thank you, Bazyle – not a boot sale but from an Ebay seller who listed it as copper. This was 6 or 7 years ago and I collected it from his house. I didn't notice any obvious discrepancy at the time or I wouldn't have completed. The label is hand-written but by whom I don't know. Didn't examine it closely as I was in the process of house-moving. Certainly, if it didn't have a label, I would say it was brass.

Not a big deal other than knowing how to deal with it for such things as soldering etc. Are there any/many caveats in dealing with one as against the other?

Rgds

Bill

[NJHParticipant @njh]

Bill

You could, of course, put your "copper" sheet back on ebay…………………………..

N

[JAParticipant @ja]

Put a bit cut off the sheet in an open pot containing salt water with a small strip of "known" copper. Keep the two apart. Connect a modern voltmeter, set on a low range, between your unknown metal and "known" copper. If there is a voltage your unknown is not copper. If no voltage it is copper. You might have to check both polarities. It may be wise to repeat this with a strip of "known" brass. No voltage would equal brass.

If you don't want to damage the sheet I am sure you could find a way of sitting the salt water on the sheet (plasticene comes to mind).

JA

[Cornish JackParticipant @cornishjack]

Thank you, Norman! …and YOUR Ebay user name is…?

Thank you also, JA. Might well give that a whirl. Given our proximity to the North Sea,(approx 20'!) salt water is no problem!!!

Rgds

Bill

[Ian S CParticipant @iansc]

Lay a bit of cloth or paper soaked in the saline solution between the two bits of metal if you don't want to start cutting the big bit up, and procede as per JA. Ian S C

[Cornish JackParticipant @cornishjack]

Thank you all …BINGO!!

It Is brass! "Walks like a duck, squawks like a duck … etc."

That brass/copper test was quite new to me. For anyone else who might need similar identification, I had to go to the AVO Pro meter to get an obvious reading – the smaller Akai wasn't sufficiently definite. Thanks again

Rgds

Bill

[Sub MandrelParticipant @submandrel]

Interesting!

Neil

[nigel jones 5Participant @nigeljones5]

Confused me….thats like comaring chalk with asbestos…..they look completely different!! Now I have been known to pause thought with brass and phos-bronze, but only momentarily!!

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