There’s no telling what will turn up at a scrap yard. You can happen upon some truly valuable pieces of metal in your yield, but their value may not immediately reveal itself to you. Scrap metal doesn’t come with labels in tidy packages. If it did, the job would be a lot easier. Instead, identifying a piece of metal falls on you, your equipment, and your own two eyes. With these common methods used to identify metals, you can ID your scrap and start separating the good stuff from the common iron.
Sometimes you really don’t need more than what you carry with you every day. A well-trained eye can identify a piece of metal simply by looking over its surface. By examining a test subject’s untouched surface, filed surface, and the surface of a fracture, an expert scrapper can deduce whether a metal is low-carbon steel or stainless steel, aluminum or lead, copper or bronze, or many other distinctions among metals that wind up in the scrap yard. Take note—if you’re not confident in your abilities, don’t try to simply eyeball a piece of metal.
A hardness test is most useful for indicating the presence of lead, a relatively soft metal and notorious neurotoxin. If you suspect you’re working with lead, you will not want to spark that lead or do anything that could lead to poisoning. Using a Mohs hardness kit, determine whether you can scratch the test subject at a low hardness. Lead only falls between 1 and 2, while iron and nickel rate at 4, and steel at 5.
This test for identifying metal takes striking rocks to start a fire to the next level. Scrape your mystery metal against an abrasive wheel and look for the sparks it gives off. The nature of the sparks or a lack thereof can indicate what your subject is. Low-carbon steel gives off long white sparks and lots of them, while nickel sparks are short, orange, and sparse.
The great schism of scrap metal is in whether a metal is ferrous, i.e., that it contains naturally magnetic iron, or non-ferrous. Examining a subject’s magnetism is thus one of the most common methods used to identify metals. Taking a magnet to your piece of scrap should help you narrow it down, and in some cases, “iron” or “not iron” is all you need to know at a given moment. In some cases, you can accomplish this with a small, handheld magnet. Sometimes, you need a little more than that. Moley Magnetics offers scrap magnets that help you separate what you want from what you need at the yard.