Bronze or brass

[DalboyParticipant @dalboy]

I know this is possible a difficult question to answer but sorting out my metal stash which most of it was left over from other projects I found an hexagonal piece of brass (On the right in the photo, I also found this other piece which by the colour of the oxidized part is more of a bronze colour.

I turned down a small portion of each piece and there is a definite difference of colour again very much a bronze colour compared to the hexagonal piece.

I suspect that I brought it to make some small prop shaft bearings many moons ago but memory fails me

Could I be correct in my assumption

[DalboyParticipant @dalboy]

[noel shelleyParticipant @noelshelley55608]

One test would be to take a small sample and heat to well above melting point ie 1050c ! at this point if brass the zinc will fume or burn off – avoid breathing the fumes ! Noel.

[pgk pgkParticipant @pgkpgk17461]

A quick punt about google came up with the link below..could be useful but admittedly the zinc test would be awkward:

https://manual.museum.wa.gov.au/book/export/html/157

pgk

[Dave HalfordParticipant @davehalford22513]

Doesn't brass change colour when put in an acid pickle due to the surface zinc being dissolved and bronze stays the same?

[BazParticipant @baz89810]

From your photo I would say round is bronze and hex is brass.

[BufferParticipant @buffer]

Derek this wont help this time but I always stamp the end BZ, PB etc when I buy stuff. Just got to make sure you saw off the correct end!

[DalboyParticipant @dalboy]

Posted by Buffer on 03/10/2021 13:47:54:

Derek this wont help this time but I always stamp the end BZ, PB etc when I buy stuff. Just got to make sure you saw off the correct end!

With the new stuff I have brought recently I have done exactly that so all of my Ali has been stamped.

[DalboyParticipant @dalboy]

Thank you all but at the moment don't have the items to be able to do some of the tests. I realize it was a long shot but from my time as a plant mechanic and have dealt with bronze bushes everything was pointing in that direction but that was before 2003 when I had to pack up work

[Phil H1Participant @philh196021]

Machining might be another indication?

For me, brass forms tiny irritating, short, sharp chips (irritating when they manage to get in your socks). Bronze that I have used always seems to form longer, ribbon type chips.

Phil H

[KWILParticipant @kwil]

Agree RH is brass, LH is bronze. Surface striation of the LH is typical of bronze bar but not definitive.

[Neil WyattModerator @neilwyatt]

Posted by KWIL on 04/10/2021 13:49:04:

Agree RH is brass, LH is bronze. Surface striation of the LH is typical of bronze bar but not definitive.

^This.

Neil

[DalboyParticipant @dalboy]

Again thank you all. Not sure of grade of bronze which I know no one will be able to say but it certainly machined nice as well as easy

[BazyleParticipant @bazyle]

Polish the end in the lathe and dob on a little vinegar. It will quickly show the crystalline structure of brass, but have far less effect on bronze. Use pieces of known material for comparison.

[JohnFParticipant @johnf59703]

My guess is Gun Metal which is in the Bronze family of copper alloys — only a guess but the colour and un-machined surface looks like GM to me

John

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