Bronze or brass

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

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.

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

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

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

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.

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

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

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

^This.

Neil

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

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.

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