Busting myths about Tin, Magnets and their reactivity

[Steven]

Busting myths about Tin, Magnets and their reactivity:

Tin comes in two Crystal structures: Tetragonal (White Tin), and Diamond Cubic (Gray Tin).

“β-tin (the metallic form, or white tin), which is stable at and above room temperature, is malleable. In contrast, α-tin (nonmetallic form, or gray tin), which is stable below 13.2 °C (56 °F), is brittle.”

Gray Tin is diamagnetic meaning repels a magnetic field. White Tin is paramagnetic meaning draws into a magnetic field.

Source: http://en.wikipedia.org/wiki/Tin


“Strong paramagnetism also decreases with rising temperature because of the de-alignment produced by the greater random motion of the atomic magnets. “

Source: http://www.universetoday.com/84358/paramagnetism/

Magnetization
“The magnetization of a magnetized material is the local value of its magnetic moment per unit volume, usually denoted M, with units A/m. It is a vector field, rather than just a vector (like the magnetic moment), because different areas in a magnet can be magnetized with different directions and strengths. A good bar magnet may have a magnetic moment of magnitude 0.1 A•m2 and a volume of 1 cm3, or 1×10−6 m3, and therefore an average magnetization magnitude is 100,000 A/m. Iron can have a magnetization of around a million amperes per meter. Such a large value explains why iron magnets are so effective at producing magnetic fields.”

Source http://en.wikipedia.org/wiki/Magnet

To consider the depth of variability goes even further: Different types of magnets may have different classifications OF that type of magnet. “Permanent Magnets can further be classified into four types based on their composition: 1. Neodymium Iron Boron (NdFeB or NIB) 2. Samarium Cobalt (SmCo) 3. Alnico 4. Ceramic or Ferrite”

Source: http://www.howmagnetswork.com/types.html

The strength of magnetism will vary between different elements including how an element will respond to certain magnetic types and even temperature can change reactivity (between the element, magnet or both). As a side thought, I don’t suppose brittle gray tin would be ideal for a solder, let alone casting, no? Are you really sure you know exactly what’s in your pewter, solder, linotype? Or how lead (being a softer metal) mixed with gray tin (at whatever amount you deem worthy) would react as a ballistic alloy? Or if you’re at the right temp to test it (or if temperature will matter with the tin type you may have present)? Or if you have a mix between white and gray tin? Or if the alloys mixed with your specific tin type hasn’t changed its Diamagnetic/Paramagnetic strength? Or if the Diamagnetic strength was even reactive enough to begin with? To conclude there’s no such thing as “plain tin”. Stating that “tin is an element” is irrelevant, it can have various crystal structures that will vary in chemical and magnetic reactivity and even density depending on its crystal type and mixture with other alloys, their amount, etc. Pure-white-tin is malleable, will melt at 449.6 degrees Fahrenheit, it’s stable, ideal for soldering and casting; and a magnet will stick to pure white tin. Thanks for reading and LET THE ARGUMENTS BEGIN!!!!!
:guntootsmiley:

-Steven

[303Guy]

Well, my pewter objects don't attract a magnet. Why would tin retain a crystal structure when molten?

[imashooter2]

What practical use is there in industry for a non metalic tin that is only stable below 56 degrees Fahrenheit?

[mold maker]

What did he say??????? I'm 6'3" and it all went way over my head.

[btroj]

I don't know that it matters at all. We use tin, it does what we need.

This sounds like the guy using science to "prove" there are lead vapors coming off a lead pot.

Like BassAkwards used to say- it only matters when it does. This one doesn't pass the test.

[cbrick]

Huh???

Ok, I promise to never shoot any magnets.

Rick

[btroj]

But Rick, magnetic bullets never miss a steel plate......

[Freightman]

No argument here as I didn't understand a word after white tin!!!!!!!!?

[Epd230]

What if C A T really spelled dog?

[Teddy (punchie)]

What did he say??????? I'm 6'3" and it all went way over my head.

I was thinking the same thing, it is way too.... early for that information or way over my head, I'm with you Mold Maker ????????????

[Steven]

The purpose of the above post was to explain that it isn’t practical to test for the presence of tin with a magnet because too many factors can change the variables of magnetism.


No argument here as I didn't understand a word after white tin!!!!!!!!?
70546
White Tin on the left, Gray Tin on the right. Source: http://en.wikipedia.org/wiki/Tin


Well, my pewter objects don't attract a magnet.
I personally wouldn't understand why a company would use white tin (being paramagnetic, stable at room temp and above) largely in raw form (90% pure or more) and then be placed in non-industrial usage. If I owned a company that made pewter trinkets, I’d use gray tin for pewter as well. In addition, even if it had some white tin in it, the mixing of other alloys may change its magnetic reactivity and stability.


Why would tin retain a crystal structure when molten?
It doesn’t. If you’re really interested in knowing if tin could be magnetic in certain conditions, I left links in the first post that explain the details.


What practical use is there in industry for a non metalic tin that is only stable below 56 degrees Fahrenheit?
There isn’t a practical usage for pure gray tin (that I know of), but its composition changes when mixed with other alloys.


I don't know that it matters at all. We use tin, it does what we need.

This sounds like the guy using science to "prove" there are lead vapors coming off a lead pot.

Like BassAkwards used to say- it only matters when it does. This one doesn't pass the test.
If you’re not interested in someone else attempting to contribute, you don’t have to participate in researching the sources they provide…. Turn your eyes slightly to the left or right and all will be ok. LOL

This morning I melted some tin that was magnetic… at 460 degrees Fahrenheit… and this tin is all over the place. Sound like steel’s melting point? Have a nice day Gents.

-Steven

[btroj]

I have NEVER heard of someone teasing for tin using a magnet. Never. Not once.

As a matter of fact many here have asked if "tin" cans or "tin" roofing was tin. Common answer is to use a magnet. If it sticks, it is steel, not tin.

Again, is is something that just isn't relevant in the casting world. Just because it exists doesn't mean it matters. That from a guy with a BS in Chemistry. We have many engineers here too, they never mentioned this. Matter of fact, I have NEVER heard of it til now.

Are we all that dumb? Nope. It just doesn't matter.

[303Guy]

But it's interesting. I've never heard of it before and I like finding out about new stuff (but I'm still trying to get my head around how tin, antimony and copper alters the properties of lead). Lead and tin melting points change with the percentage tin as does the strength. Too much lead and it gets weaker, too much tin and it gets weaker. Melting point does the same. Now they're talking about magnetic momentum! Anyway, it's all fun.

[Steven]

I have NEVER heard of someone teasing for tin using a magnet. Never. Not once.

As a matter of fact many here have asked if "tin" cans or "tin" roofing was tin. Common answer is to use a magnet. If it sticks, it is steel, not tin.

Again, is is something that just isn't relevant in the casting world. Just because it exists doesn't mean it matters. That from a guy with a BS in Chemistry. We have many engineers here too, they never mentioned this. Matter of fact, I have NEVER heard of it til now.

Are we all that dumb? Nope. It just doesn't matter.

Brad you sound really upset? Are you alright? I haven't called anyone dumb.... These forms as an opportunity for new guys (like me) to debate, discover and learn and find out what others have learned about things; Simply for the sharing of information. I for example learned something interesting a couple days ago, posted it and was ready for a healthy debate. You mentioned a degree, remember in college our professors taught us to use specific methods when sharing research information? There wasn't any name calling or downing anyone, I left sources, exposed my hypothesis and acknowledged I was ready for a debate of the information I shared. It's just sharing information for the purpose of a debate, for the purpose of research for those still learning (me being one of them). Did something bad happen? I'm trying to figure out why you're acting aggressive? I hope you're alright....

303Guy, thanks for appreciating this. I only found out a couple days ago and you could have fooled me. This **** yard had 3 guys with a background in metallurgy and it was interesting see them argue about tin properties and they really lost me when they brought up magnetism. When you're still a student of physics and see people you felt were professionals argue what they keep calling facts, it can encourage someone to pick up the research for themselves and what I did find was really interesting, or at least interesting to me any ways. During this I also found opportunities to find tin for practically nothing in cost so it came with a valuable benefit.

-Steven

[303Guy]

So I had a look at those links and ended up on magnets. Then the beer engaged and my brain disengaged. But I learned a whole heap about magnets. Tin has ten stable isotopes and even has a radioactive isotope. It also makes good boolit alloy.:-D I didn't know tin had such a long history.

Needless to say I had no idea tin formed a non-metallic state (the α-tin) at low temperatures - like in your fridge! But tin has to be pretty pure for that to happen. They say that non-metallic tin has little or no uses. It's non conductive too.

Steven, while you're out there researching, could you find out more about copper/tin/lead alloys please? Antimony in the mix too? It would be greatly appreciated.

Another question; why does and alloy of tin, antimony, a little copper and lead have the same hardness and strength as the same alloy diluted with an equal amount of lead added? I've just done a hammer test on two samples and they appeared to resist flattening equally well. (Unless I took two samples of the same alloy ..... [smilie=1: ) The samples did behave differently initially with the diluted alloy flattening easier at first but once the un-diluted sample began to flatten it ended up the same thickness but it did seam to take more blows to get there. OK, so they're not exactly the same but more similar than the amount of dilution would have made me expect.

[Whiterabbit]

Busting myths about Tin, Magnets and their reactivity:

As a side thought, I don’t suppose brittle gray tin would be ideal for a solder, let alone casting, no? Are you really sure you know exactly what’s in your pewter, solder, linotype? Or how lead (being a softer metal) mixed with gray tin (at whatever amount you deem worthy) would react as a ballistic alloy? Or if you’re at the right temp to test it (or if temperature will matter with the tin type you may have present)? Or if you have a mix between white and gray tin? Or if the alloys mixed with your specific tin type hasn’t changed its Diamagnetic/Paramagnetic strength? Or if the Diamagnetic strength was even reactive enough to begin with? To conclude there’s no such thing as “plain tin”. Stating that “tin is an element” is irrelevant, it can have various crystal structures that will vary in chemical and magnetic reactivity and even density depending on its crystal type and mixture with other alloys, their amount, etc. Pure-white-tin is malleable, will melt at 449.6 degrees Fahrenheit, it’s stable, ideal for soldering and casting; and a magnet will stick to pure white tin. Thanks for reading and LET THE ARGUMENTS BEGIN!!!!!
:guntootsmiley:

-Steven

Ooooookayyyyy. Where to start?

Let's start with paramagnetism. Does NOT mean a magnet will stick, it means you have a weak response to an applied field. ALUMINUM is paramagnetic. That's why they were used as car speedometers in older cars (really old cars). The spinning of the engine (or wheels) translated to a magnetic field that the needle would respond to. There's a difference between static magnetism and dynamic magnetism. Case in point, run DC current through a transformer and you create a magnetic field, but you don't get a response on the secondaries.

http://en.wikipedia.org/wiki/Paramagnetism#Systems_with_minimal_interactions

Next, Grey tin? White tin? We can't say "tin is elemental, tin is tin?" Well actually we CAN say exactly this. Why? We are casters. The INSTANT we take the in to liquidous, grey tin and white tin cease to exist. These phases ONLY exist in the solidus phase. And if no non-equilibrium structures exist, then grey and white tin will exist exactly as defined by the tin phase diagram.

http://upload.wikimedia.org/wikipedia/commons/4/47/Phase_diagram_of_tin_%281975%29.png

1 bar is roughly 1 ATM. So we don't form grey tin unless VERY cold. Think it matters? It doesn't. It means your PURE tin will go through a phase transformation in the winter, and right back to white tin in the summer. And it doesn't matter HOW cold your winter gets, as soon as it goes in the pot, it is white then liquidus.

The moment you get ANY alloy content in there? throw that phase diagram out. You need a compositional phase diagram. Like this one:

http://www.sv.vt.edu/classes/MSE2094_NoteBook/96ClassProj/pics/Pb_Sn.GIF

After 2% lead, you get ZERO tin. That's right. Add 2% lead to tin and you get ZERO pure tin in your alloy. you only get alpha and beta alloys, both at very high tin content. but never zero. And no pure tin, and you can't form grey tin in the winter.

to answer post #2, tin DOESNT retain crystallinity when liquid. Only when it passes the solidus line does it recrystallize. And while we are talking about metallic vs nonmetallic, don't confuse that for noncrystalline! We can see from the phase diagram that Grey tin is diamond cubic.

Listen, I'm glad the arseload of "tin" you bought melts at 460. I really am. Enjoy the fruits of your purchase! But this warpath is childish. The other guys in the chat room won't apologise, and your evidence here is not proving you right. Only the melting at 460. That's all you needed to say. Which you did. 11 posts later.

[hermans]

Wow, this is really cool....and all I want to do is just cast good shooting boolits, like I have done the last 25 years, just using my gut feel......

[Steven]

Thanks Whiterabbit, I love what you provided, that was very helpful! There's so much information and it's easy to get lost in cyber world. I'll have to find some time to read more up on that.

The one sample I melted did melt at 460, but others WAY higher so now I have to go through everything sorting out what's actually tin, what's an alloy mix or probably just steel, the mines out here dump some strange containers at scrap yards of surprising alloys one would never expect for cargo containment, I know they work with vast chemicals and participate in experimental methods of mining so I'll work with caution. One quick note, I have noticed several specific individuals on these forums found it offensive to exchange information I researched from other sources instead of relying on these specific individuals as my only source. I welcome their information with open arms, but I don't feel comfortable narrowing down my learning environment to just 1 person or 1 group, I welcome their information, but I don't stop learning with just them. In addition it would be nice if others would go the the extent you did Whiterabbit, I love the way you took advantage of debating my information and responding with links to other sources that allowed me to see the whole who, what, why, how instead of just taking your word for granted, and you did it in an introduction friendly way, I wish others responded more like you do.

303Guy, I'll do my best, but It'll take some time because I know very little about those alloys. It was fun watching lead (heated to 550 degrees) and seeing the lead atoms transfer into tin and melt it. I lost where I found that video, I'll have to hunt it down, these metallurgist use some pretty cool equipment.

-Steven

[leeggen]

Steve,
It's not a matter of debating what is or isn't in casting we just add a little tin to make better pouring lead for our cast bullets. It doesn't concern me anyway that it is mag. or nonmag. It really sounds to me like you want everyone to think you are more together than the real world hands on casters that have been doing this for years. No put down just my take on the post. No one is hurt upset or mad at you just that we do, what we do for fun and relaxation. No debate with a college book just hands on biulding something from a mix of metels.
CD

[Whiterabbit]

The background as I understand it, is that he got hundreds of pounds of tin at an amazing price. So amazing that when he mentioned it to the chat room, they doubted him (after several asked repeatedly to buy some from him, I might add). When Steven mentioned the seller checked it with a magnet before declaring it tin and selling it to him (mildly magnetic), noone in chat believed he actually bought tin.

I personally believe he started this thread to "prove" to the disbelievers in chat that tin could stick to a magnet, and that his purchase was justified.

My personal response is, if it melts at 460 as stated, the disbelievers can go to heck, and Steven can enjoy the fruits of his labor. No need to go on a theoretical warpath to prove tin is or is not magnetic, it's just childish (I'll show THEM I was right!). He's not gonna get an apology. And this sure makes no difference at MY house!

[Defcon-One]

OK, so you melt it and it is Tin again (White Tin), the stuff that we use. So who cares?

I think that "Tin is Tin" says it best! Why create an issue where one does not exist?

Next issue.....