How to tell if it's brass or plated?

[gravygrabber]

Found a table lamp today. Looks like a cast brass body so I grabbed it out of the dumpster. Someone cut the cord off already but that's pretty common. Seems like they don't know there is more copper in that TV yoke then the power cord but that's fine with me I'll come pick the meat off the ribs! Anyway the body of the lamp is heavy but it doesn't stick to a magnet. It has a marble base to it. Anyway to further confirm what it is?

[Phantoms001]

The only way I know how to check is put a grinder to it. If it's yellow inside it's brass, if not, it is mostly "pot metal".

[MetalEarthRecycling]

Grinder or file works well or really anything that can scratch it deep enough. Sometimes they are made of cast aluminum with a goldish surface coating to make them look like brass.

[BRASSCATCHER]

Going to be zinc.

[Yunkman]

I grew up using the term 'puter' when identifying some type of junk metal. This thread mentions 'pot metal' and 'zinc'. I've sold stuff as cast aluminum when I would have called it 'puter' many years ago. On the other hand, I took apart what appeared to be a brass bearing off a shaft the other day and the center of it was WOOD !!

[MetalEarthRecycling]

Going to be zinc.

I agree with that. I rarely Get Die cast zinc, if i have a piece i Usually throw it in with cast aluminum. I should probably stop doing that and make a pile since it is different and worth a little less.

[gravygrabber]

The only way I know how to check is put a grinder to it. If it's yellow inside it's brass, if not, it is mostly "pot metal".

I hit it with the grinder and it looks like aluminum to me and doesn't stick to a magnet. Could it be cast alum. ?

[MetalEarthRecycling]

I would take a sledge hammer to it and break it into some pieces. Might help you to see the metal a little better and help you determine. Or just ask your yard/buyer if its okay if 1 piece of die cast zinc goes in with your cast aluminum load.

[hobo finds]

Die Cast zinc is a lot less than cast aluminium by me. .10-.15 vs .50 - .55 lb

[BigTime]

Die Cast zinc is a lot less than cast aluminium by me. .10-.15 vs .50 - .55 lb

And to know the difference between the two, THE WEIGHT. Zinc is a lot heavier than aluminum.