The Home Machinist!

Heat it with a torch and see how it melts

guys, there is an easy way to determine brass from bronze. place a piece of brass in acid and it will turn black. Bronze will turn a flat red color. Michael

What kind of acid?

Brass placed in strong acid will turn black. bronze placed in a strong acid will tun a dull red. make sure to remove oil on the material. I use hydrochloric acid

hydrochloric acid

michaellynn2 wrote:guys, there is an easy way to determine brass from bronze. place a piece of brass in acid and it will turn black. Bronze will turn a flat red color. Michael

That's not a reliable test, especially if one chose nitric acid, which readily dissolves zinc and copper.

HCl (hydrochloric acid) will readily dissolve tin and zinc. It does not dissolve copper, however (unless oxidized), so if brass is inserted in a dilute HCl solution, it will turn red, just as bronze would (I've done that on numerous occasions, to remove fire coat from reformed and annealed rifle cartridges).

Dilute sulfuric acid will dissolve copper oxides, as well as zinc and tin. End result? Red (the remaining copper).

I am unaware of an acid that will respond as suggested, but that doesn't mean there is no such acid. I am limited by the three I mentioned, as they were used daily in the refining of precious metals.

H

I have been in the plumbing business for 33 years and can tell the difference between brass and bronze. Brass when left in muratic acid will turn black. Bronze will turn a dull red. Putting the brass in muratic acid will weaken it. It is best to put a sample in the acid.

Here is a list of alloys from Kramer: http://hkramer.com/3KramerAlloyProperties.pdf

These are used for making castings, which will not be exactly the same for brass or bronze bar, but it's close enough to realize there is some confusion in naming brass and bronze.

http://hkramer.com/

I buy my ingots from Kramer, and just cast four #8 switch frogs out of their C99700 White Tombasil; is it a brass or bronze?
Below is a photo from a previous pour, I use C99700 for casting smaller parts also:

Phosphoric acid will dissolve zinc but not tin or copper.

John Hasler wrote:Phosphoric acid will dissolve zinc but not tin or copper.

Hmmm, that means rust remover such as naval jelly, and Coca Cola, should do the test job. If someone actually does this please let us know your findings. w.

RONALD wrote:
http://hkramer.com/

Thank you -- Great resource on that site:

http://hkramer.com/foundry-data-handbook.html