What makes some brass magnetic?
A discussion started in 2007 & continuing through 2017(2007)
Q. I have been collecting brass from thrift stores, and always check it with a magnet. I can easily tell brass plated items from solid brass this way. However, some items, although marked "Made in India" as much brass is, and looking just like solid brass, show a very slight_ attraction to a magnet. Is there an alloy of brass that contains iron?Dave Blanchard
Hobbyist - Portland, Oregon, USA
A. Brass is non magnetic.
The items you have bought are probably brass plated mild steel. It is quite common.
A. Iron melts at 1538 °C. Bronze under 1000 °C depending on its alloy. So, iron is not considered an alloy for any bronze but rather a contamination; in my opinion, not enough to attract a magnet ... unless it is added intentionally for cost reduction purposes.
Monterrey, NL, Mexico
A. Geoff is right, there is loads of brass plated steel goods around, so beware.
There won't be enough Iron (if any) in brass (which is a copper/zinc alloy) to be magnetic, but in what we in the UK call Nickel Aluminium Bronze (might also be called Aluminium Bronze) there is about 4.5% each of Iron and Nickel; this makes it a bit magnetic.
It is however unlikely that your brass items are of this more specialised high strength alloy.
Ship Repair - Plymouth, UK
A. There's also a possibility that some steel wool [linked by editor to product info at Rockler], filings, powder or wire was added in the mold before pouring the bronze. That would make it somewhat magnetic and less expensive to produce.
Monterrey, NL, Mexico
October 28, 2017
Q. I have a brass looking item that is very slightly magnetic with a powerful rare earth magnet and reacts vigorously with nitric acid. I thought it might contain nickel which is one of only four magnetic metallic elements but it doesn't react with acid. Maybe that aforementioned aluminum bronze. I will XRF it next week.ken mason
- weimar, California usa
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