How to Tell the Difference Between Stainless Steel and Aluminum

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Magnet Test:


Hit with a magnet. If it sticks, it is not aluminum, but rather 400 grade stainless steel, or just normal steel.
The only elements that stick to a magnet are nickel, cobalt, and of course, iron.
As an aside, tungsten carbide doesn’t stick to a magnet. In fact, tungsten carbide is actually a powder. What is commonly called “carbide” is actually cemented carbide, which is cobalt impregnated with tungsten carbide (WC). The cobalt is what causes carbide tools to attract a magnet. (I have written about scrap carbide before)

If you grind the steel with a grinding wheel, and it throws off a glow of sparks, then it is steel. otherwise it isn’t steel. So if it is non-magnetic and it gives off sparks, then it is most likely 3xx series stainless steel.
Rust Test:
Aluminum doesn’t rust. Stainless steel CAN rust, and contrary  to popular belief WILL rust eventually, especially in extreme conditions.
Density test:
Grab a similarly sized chunk of regular steel. Aluminum is about 3 times lighter than stainless steel. If your sample doesn’t seem light compared to the regular steel, then it is probably also steel.

{ 21 comments… read them below or add one }

Rowdy February 17, 2011 at 1:25 pm

Well timed, I just cut up a sheet of stainless for today's trip to the yard.

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The Irrationalist February 17, 2011 at 4:54 pm

Cool. What were the prices like near you?

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Anonymous April 29, 2011 at 12:02 am

what would pots and pans, spoons and forks, that a magnet does sticks to that appear stainless be considered?

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The Irrationalist April 29, 2011 at 1:27 am

These are (usually) 4xx series stainless.

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margaret March 8, 2012 at 3:03 am

back walk plate of a semi? (the thing that goes on the frame right behind the cab) aluminum or steel and worth scrapping? can’t believe all the stuff i may have around here that I may be able to get a lil greatly needed $$ off of. Thanx so much for your site!

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ScrapMetalJunkie March 8, 2012 at 11:11 pm

I cannot say without testing it myself, but it sounds like it would be aluminum. Check it using the methods described above.

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btodean April 24, 2012 at 1:33 am

Whole aluminum cans, as far as bringing them to a can recycling plant & getting 5 cents ra versus crushing and bringing to a scraping yard?

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ScrapMetalJunkie April 24, 2012 at 2:06 am

it takes 32 aluminum cans to make a pound, so you will always be better selling them for 5¢ per can.

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Jason October 9, 2012 at 12:55 pm

scrapmetaljunkie,

i have three pallets with a total of about 30 sheets of 8×13 and about 3/8 thick. the sheets are pretty heavy and they were used in a manufacturing factory but got new machines and now i want to scrap it. i would like to know if its aluminum or stainless steel and how much would it be to scrap stainless steel. it is non-magnetic and when i scratch it with a key it does scratch easily and has a shine under the dull grey on top. a scrap yard told me that if it is heavy then it is steel. i just would like to know if it would be worth scrapping and getting a truck for it. thank u

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ScrapMetalJunkie October 9, 2012 at 9:09 pm

If your estimate of 6000 lbs is correct, then the scrap should be worth roughly $3000 dollars. Aluminum is worth a little less than 50¢ per pound and 3xx grade stainless steel is worth about the same. If it sticks to a magnet, then it is worth roughly maybe $500. If you have that much of it, and it doesn’t stick to a magnet, bring a sample of it to several different scrap yards and ask them to give you a quote. They will compete for your scrap based on how much you have, and the best scrap yards will analyze the scrap to give you the best quote possible. The stainless steel is worth dependent on what type of alloy it is; for example, 316 SS is worth more than 304 SS.

Best of luck

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Don Smith December 12, 2012 at 11:22 am

You have a great site. I have an alum building which I bought at Lowes. It is rusting so now I don’t know
what I have. Is it worthwhile dismantling and selling at a scrap yard.?

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ScrapMetalJunkie December 13, 2012 at 3:16 am

Aluminum doesn’t rust, so I’m guessing you mean corroding? Either way, the aluminum will be worth about 50¢ per pound if it isn’t contaminated.

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RICHARD May 7, 2013 at 10:45 am

I have a long pipe tube, 390 cms, very heavy, silver, shiny, out in weather for months and no rust, magnet sticks, sparks from grinder. How do I tell if it is galvanised steel or stqainless steel ?

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Ernestine Gonzalez September 4, 2013 at 10:58 pm

I want to build a faraday cage for my generator. Should I use aluminum, stainless steel or what. Do nI need to line the box once it is built?

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James Bangert January 1, 2014 at 5:36 pm

I come across a lot of pots and pans which are made of aluminum, but have steel handles attached with rivets. Is there a simple, (cost effective) way to separate the handle from the pan?

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ScrapMetalJunkie January 2, 2014 at 1:28 am

Breaking the handle off the pan with a brass hammer is the fastest way, I’ve found. You need to hold the pan/pot in a vice and then just pound it off without holding anything back. It’s the definition of brute force, but it is cost effective.

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James January 2, 2014 at 11:56 pm

Thanks for your reply, I’ll give that at try. Thanks also for this very informative website.

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wily February 24, 2014 at 6:35 pm

nickle is NOT magnetic…

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ScrapMetalJunkie March 3, 2014 at 3:08 pm

Nickel is one of the 4 magnetic elements: iron, nickel, cobalt, and gadolinium.

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tomcatn75 March 23, 2014 at 7:53 am

Good website. Great reference
material. Thanks for your time aund work here.

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josh April 16, 2014 at 10:44 pm

What BT alloy aluminum.. does it spark is it magnetic

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