tin cry, or not?

[lylejb]

Recently, I've begun to look for pewter in thrift stores, for tin on the cheep:smile:

I've came home with two plates: the first I'm 99% sure it's the real thing. It makes a faint sandy / crackling sound when bent, does not try to spring back, is heavy as expected for pewter. It is, however, unmarked.

The second is marked " genuine fine pewter made in USA". It doesn't, however, make any sound when bent. Why? I thought tin / high tin alloys were supposed to "cry"/ crackle when bent.

Also, I noticed that 95 tin 5 antimony solder doesn't make any sound when bent.

Is tin cry a sometimes thing? Does it require a very high (above 95%) tin alloy to happen?

I'm learning quickly to spot most wilton / fakes by color, and my first plate looks right. But I don't understand why it "crys" and the marked genuine plate doesn't?

What say you?

[Lee]

pure tin will, don't know about (high) alloys though.
Below a certain temperature pure tin crumbles, don't know about (high) alloys either.
Interesting question. Just how DOES one tell the %age of tin in a chunk of unknown metal??
Melting point?? Hardness?? Might be good starting points....

[lwknight]

My pewter never made any sound when bent. Its too thin.
It bends easily though.

[lylejb]

I did a bit of testing. Using a lee 558 158rf mould that casts at 162 in ww / lead, I melted each plate separatly.

The "genuine fine pewter" marked plate casts an average 108.3 grs, and made perfectly filled out boolits from a dead cold mould.

The unmarked, but cries plate casts 109.4 gr boolits from the same mould, with the same perfect fill out from a cold mould.

Both are mirror bright, almost like polished silver. Both melted at 3 on a lee 10 lb pot. (3 won't melt wheel weights on my pot)

Well, they're not exactly the same, but close enough.

I came home with 2 lbs of this metal for $7, not to bad for a first try.

[geargnasher]

Use a graduated cylinder and water to determine the volume of a sample. weigh the sample on your most precise scales. convert weight to grams and use the mL, or CC, volume on your grad. cylinder.

divide to get grams per milliliter, that is your DENSITY. Pure lead is like 11.3 and Pure tin 7.28 g/mL.

Then determine the melt point of your alloy. If it's close to mostly tin, it will be low enough to check with a cheap probe-type candy or meat thermometer that has been calibrated with boiling water (compensated for your altitude).

If the melt point and SG agree closely, you can assume it's real pewter.

Gear

[troy_mclure]

ive found that pewter ingots have a gold tinge when they cool.

[captaint]

Yes. High tin alloys do have that goldy look, when melted into ingots. One could also take a sample of alloy to the scrap dealer to get it analyized. Most do it for free. They will want to buy your high tin alloy though. enjoy Mike