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#1
Old 08-17-2013, 04:36 PM
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Is there a non-destructive way to test titanum jewelry to confrm it's titanium?

Got an inexpensive titanium ring the other day for less than 10 dollars off ebay. I thought I measured my ring size correctly but it's too big (size 15) and I'll probably use it as a key ring fob. I m curious if there a non-destructive way to test that it's actually titanium. It says "titanium" inside the ring but who knows. It's seems lighter than steel, almost aluminum like but not quite that light, and it has a shiny surface like stainless steel.
#2
Old 08-17-2013, 04:52 PM
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If you expect the ring to be 100% titanium, you might be able to do an accurate measurement of its volume by dropping it in a graduated cylinder and seeing how much water it displaces. Then you could figure out its density and see if it compares to the book number for titanium.
#3
Old 08-17-2013, 04:58 PM
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If it's harder than aluminum and lighter than steel, what else is it likely to be?
#4
Old 08-17-2013, 05:23 PM
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Originally Posted by aNewLeaf View Post
If it's harder than aluminum and lighter than steel, what else is it likely to be?
Really cheap steel?
#5
Old 08-17-2013, 06:28 PM
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Originally Posted by leahcim View Post
If you expect the ring to be 100% titanium, you might be able to do an accurate measurement of its volume by dropping it in a graduated cylinder and seeing how much water it displaces. Then you could figure out its density and see if it compares to the book number for titanium.
Eureka!
#6
Old 08-17-2013, 06:30 PM
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Originally Posted by Amateur Barbarian View Post
Eureka!
You're running naked through the thread, aren't you?
#7
Old 08-17-2013, 06:53 PM
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With a magnet, you can confirm whether or not it's iron or steel. Or that it has iron or steel in it. Or maybe cobalt. Titanium's not particularly magnetic.
#8
Old 08-17-2013, 07:01 PM
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Originally Posted by Ethilrist View Post
With a magnet, you can confirm whether or not it's iron or steel. Or that it has iron or steel in it. ...
Quote:
... Ferritic and Martensitic stainless steels are magnetic.
Austenitic stainless steels are non-magnetic. ...
CMC fnord!
#9
Old 08-17-2013, 07:42 PM
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Stainless steel is not magnetic either.
#10
Old 08-17-2013, 07:46 PM
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Originally Posted by The Niply Elder View Post
Stainless steel is not magnetic either.
I have two stainless knives stuck to the magnetic rack in my kitchen. I'd call them "stainless steel"; is there a different type?
#11
Old 08-17-2013, 07:57 PM
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Interesting, the stainless steel in familiar with is nonmagnetic. There's probably specific heat treatments that get the magnetic qualities back.
#12
Old 08-17-2013, 08:20 PM
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Originally Posted by The Niply Elder View Post
Stainless steel is not magnetic either.
As tellyworth has already noted, some 'stainless steel' is indeed, 'magnetic'.
There are many different types (grades?) of stainless steel and some will not attract a magnet.
The 'magnet test' is not an accurate method of determining whether or not something is 'stainless steel'. There are some (albeit, they're not all that prevalent) scrap metal recyclers that will attempt to scam one into thinking that the scrap in question is not stainless steel, simply because a magnet won't stick to it.
The more honest and reliable recyclers will invariably use a more accurate method to determine what type of metal you have brought to them.
I speak from experience, I once found a 'billet' of metal on the side of the road, it was about the size of a 1 gallon paint can, yet weighed an incredible amount. (I couldn't lift it, I had to rig up a ramp in order to roll it up into the back of my truck.)
It 'looked' like stainless steel, yet a magnet would stick to it. The first scrap yard I took it to did the 'magnet test' and offered me $1.50/lb, telling me it wasn't stainless steel.
Not happy with this, I took it to a more reputable recycler. They used a tester that resembled a 'gun', it had two electrode/prongs that they touched to the object which gave a readout on the exact composition (isn't technology wonderful?) of the metal.
Long story, short...
I ended up getting almost triple the amount, that I was originally offered.

Moral... Get more than one 'opinion', and if possible have it tested electronically. I don't know if the tester that was used in my case would work for you, but I don't see why not.

It turned out that it was stainless steel, it was some type of special 'grade' that a magnet would stick to.
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Last edited by JBDivmstr; 08-17-2013 at 08:25 PM. Reason: Info on 'special grade' of S.S.
#13
Old 08-17-2013, 11:51 PM
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Step right up and watch a man's opinion change before your very eyes!

I didn't want to threadshit but the OP paid ten dollar American for a titanium ring and now wants to make sure it's really titanium? Who cares? It was ten bucks and a decent assay (assuming he doesn't have the precision tools to play Archimedes with it) will cost more. Enjoy the ring for what it is, which is costume or art jewelry made out of a base metal. Drop it on concrete and if it shatters you didn't want to wear tungsten carbide anyway. And if it's only stainless, scratches add character. But whatever it is it ain't precious or even noble.

Now, don't get me wrong. Titanium can be beautiful, especially that iridescent effect you can get with it. I still have an inch square sheet of titanium that had been hit with a blowtorch; it was the first time I saw the stuff (~1965) and I was enchanted and immediately saw potential for art jewelry. The deep colors can be butch, though Sig Sauer is using it to dress up its latest girl guns. And manufacturers use magnetron ionization to deposit it on quartz crystals, making spectacular cocktail rings that would set off whatever little, black dress a lady would like. And that Timoku faux woodgrain is wicked cool. Y'know, if a guy happened to figure out the ancient process (I'm thinking it involves a resist and heat or acid) and had some cheap, plain bands he could have some fun and maybe make some money, especially if his daughter is going to rent a shelf in an artsy jewelry shoppe.

Where did you say you got that ring?
#14
Old 08-18-2013, 02:56 AM
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Ebay- My point was just pure scientific curiosity in that it was so cheap and being too larger had no further utility, but I'd prefer not to use a Dremel grinding wheel on it to test the spark color composition.
#15
Old 08-18-2013, 05:37 AM
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As pointed out Ti will go all sorts of colours if heated with a blow torch and retain the colours which most metals wont. Try to stop when its red or peacock blue as it goes sort of muddy straw right after, and its a swine to get back to plain metal!

Made that mistake when experimenting with hand beating Ti !
#16
Old 08-18-2013, 06:56 AM
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Quote:
Originally Posted by leahcim View Post
If you expect the ring to be 100% titanium, you might be able to do an accurate measurement of its volume by dropping it in a graduated cylinder and seeing how much water it displaces. Then you could figure out its density and see if it compares to the book number for titanium.
How would this determine the material? If you took 3 rings, all the exact same size, one titanium, one steel and one aluminum, dropped them in water, would they not displace the exact same amount of water?
#17
Old 08-18-2013, 07:06 AM
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Originally Posted by racer72 View Post
How would this determine the material? If you took 3 rings, all the exact same size, one titanium, one steel and one aluminum, dropped them in water, would they not displace the exact same amount of water?
Now that I think about that for a second, IMHO, you are absolutely correct.


I'm sure there will be someone along later that will know for sure, though.
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#18
Old 08-18-2013, 07:10 AM
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Originally Posted by dropzone View Post
...
Now, don't get me wrong. Titanium can be beautiful, especially that iridescent effect you can get with it. I still have an inch square sheet of titanium that had been hit with a blowtorch; it was the first time I saw the stuff (~1965) and I was enchanted and immediately saw potential for art jewelry. The deep colors can be butch, though Sig Sauer is using it to dress up its latest girl guns. ...
Damn, that sure is a purty pistol!
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#19
Old 08-18-2013, 07:25 AM
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Originally Posted by racer72 View Post
How would this determine the material? If you took 3 rings, all the exact same size, one titanium, one steel and one aluminum, dropped them in water, would they not displace the exact same amount of water?
Yes. But the rings themselves weigh different amounts, so you measure the density.
(With a more accurate scale than most Dopers have handy)
#20
Old 08-18-2013, 07:45 AM
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Probably not worth it, but would the OP settle for a semi-destructive test? That is, a test which would destroy it if it's not titanium, but leave real titanium unharmed?
#21
Old 08-18-2013, 09:56 AM
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Originally Posted by Ethilrist View Post
Really cheap steel?
Pretty sure that light weight is one of the hallmarks of expensive steel, not cheap steel.
#22
Old 08-18-2013, 09:59 AM
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Sometime ago there was a thread about determining gold content. I posted this as a simple way of measuring density, needing only a glass of water, a skewer, a ruler, some thread and some aluminium foil. My experience was that you can get remarkably good estimates of density this way. Get something close to 4.5 and there is a good chance it is Titanium.

However there are claims of cheap alloys that are as low as 10% Ti. If there is a lot of aluminium in the alloy it might be hard to tell from the density alone as there is scope to build an alloy of Titanium, Aluminium and Iron that could have the right density, and the right lustre.
#23
Old 08-18-2013, 10:22 AM
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If it were my ring, I would stick it in the scanning electron microscope I use at work, and use energy-dispersive X-ray spectroscopy (EDS) to perform elemental analysis.
#24
Old 08-18-2013, 10:35 AM
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Originally Posted by Crafter_Man View Post
If it were my ring, I would stick it in the scanning electron microscope I use at work, and use energy-dispersive X-ray spectroscopy (EDS) to perform elemental analysis.
Yes, there are nondestructive testing methods, if you have access to them. EDS, X-Ray Fluorescence, which uses the same principle, but without the microscope, or X-Ray Diffraction.
#25
Old 08-18-2013, 12:50 PM
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Originally Posted by AaronX View Post
Yes, there are nondestructive testing methods, if you have access to them. EDS, X-Ray Fluorescence, which uses the same principle, but without the microscope, or X-Ray Diffraction.
We'll... I'll have to get myself down to Radio Shack and get one of those.
#26
Old 08-18-2013, 12:51 PM
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Originally Posted by Chronos View Post
Probably not worth it, but would the OP settle for a semi-destructive test? That is, a test which would destroy it if it's not titanium, but leave real titanium unharmed?
Sure, what do you have in mind?
#27
Old 08-18-2013, 06:51 PM
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Not sure exactly, but you might be able to do some sort of scratch test, or something like that.

I suppose we should also ask if the ring has any setting, or if it's just all metal, since a setting would complicate the density method.
#28
Old 08-18-2013, 07:14 PM
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Google says iron corrodes in sulfuric and hydrochloric acids, while titanium does not. No idea of the details though, or if that would make a practical test.

ETA: I have a few pieces here of either surgical stainless steel or titanium, and I wouldn't mind minor damage to a portion of it to find out which it is. So if there's a test that's easily done at home I could give it a try. Don't have a dremel though.

Last edited by tellyworth; 08-18-2013 at 07:17 PM.
#29
Old 08-18-2013, 09:32 PM
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Titanium does corrode in strong acids, and a bit in diluted hydrochloric. That's what keeps it from being noble.
#30
Old 08-18-2013, 10:33 PM
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How about trying to anodize it? You only need coke and a 9V battery: http://graysci.com/chapter-five/tita...n-technicolor/ I think you should be able to polish off the coating if you don't want it.

Has anybody mentioned trying to sell it at a pawn store or junkyard and having them analyze it for you?
#31
Old 08-19-2013, 01:44 AM
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There's a much simpler way to perform Positive Material Identification:

http://niton.com/en/metal-and-al...plications/pmi

http://olympus-ims.com/en/applic.../handheld-pmi/

http://bruker.com/products/x-ray...lloys-xrf.html
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