Zink v.s. Lead

Alloys always melt at lower temperatures than their constituent metals. This is due to atomic size mismatch which makes the resultant crystal less stable thermodynamically. This difference can be substantial, as this phase diagram for lead-antimony shows:

Pb-Sb_zpsyaa98rgi.jpg


You can see that pure lead on the left melts at 327.5°C, pure antimony on the right at 630.8°C. In between the various blends all have declining melting points until you hit the minimum at Pb-12%Sb, with a melting point of 252.2°C. This composition that yields the lowest melting point is called the eutectic composition. There are some alloys that will actually melt in the palm of your hand, notably the bismuth-tin eutectics.
 
No... the wind didn't die down today so didn't feel like wasting propane and having the heat all blow away...but I did drop that piece on the cement floor and it made a dull "thunk" not a "klink" as someone suggested it would do if it was Zink .
 
gnmontey said:
It left a very stange scum in the the pot when we tried to melt it?

Black oily crap.

M
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Lead pipe is usually close to pure lead. Pure lead melts at a higher temperature than lead alloys. I've added pure lead ingots and antimony lead ingots to a melt. The antimomial lead melted immediately but had to jack up the heat to get the pure lead melted.

The black oily crap is from the inside of sewer pipes, and it really is "crap". :)
 
So I went over to the "old site" where they still speak in some foreign language;

Melt points in Fahrenheit;


pure lead 621
monotype 512
linotype 462
WW 560 (may very a bit because of diff. manuf. contents)
10:1 563
20:1 590
30:1 600

Antimony content will lower melting point in all.

Zink 786
 
jethunter said:
The black oily crap is from the inside of sewer pipes, and it really is "crap". :)
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OK..... I just washed my hands for the Nth time now. LOL.

Seriously, I don't think it is sewer pipe. It 's quite clean with just a bit of garage dust on it. Some one had it squirrelled away to make sinkers.

Still strange that I noticed the black scum in the pot after it was added and later removed.

M
 
gnmontey said:
OK..... I just washed my hands for the Nth time now. LOL.

Seriously, I don't think it is sewer pipe. It 's quite clean with just a bit of garage dust on it. Some one had it squirrelled away to make sinkers.

Still strange that I noticed the black scum in the pot after it was added and later removed.

M
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Most lead pipe was specifically made to be waste and sewer pipe, because nobody uses lead pipe for water supply. The foul black crap could be anything. Don't eat it or smoke it and wash your hands and you should be fine. :)
 
Here is a pic of it getting folded up so that it would fit in the pot.

PIPE.JPG

M
 

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yomomma said:
Looks more like old Bell sheathing
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The guy this came from did work for Telus? The other stuff I got from him was 5/8" lead wire and some very soft sheathing.

This piece was odd in that it was defiantly pipe shaped, seamless and harder.

M
 
The lead wire I cut up with a bolt cutter just because they opened wide enough. The sheathing I cut up with a set of tin snips.

I don't think I would have gotten very far trying to cut up that piece of pipe up with the bolt cutter.

A swack with the axe left a divot but not much of one.

I'm just really curious as to what it actually is?

Regardless, it's gone to a good home, fingers284 is going to turn it into cannon projectiles, if and when he manages to melt it.

M
 
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An update on Monty's "mystery metal". I had a chance to give er another go last night... I cut a few small strips from the bigger piece so I wouldn't pollute a full batch of lead with this unknown entity. when the lead melt was At 650 deg the strips just floated on top but at 700 deg they melted and mixed in with the lead without a trace of anything untoward. So this stuff wont melt at a pure lead threshold (621) but will well before the zinc (785) threshold is even close. All this assumes my Lyman Thermo is accurate, the only reference I have to compare it to is that the lead melt still absolutely pourable at a reading of 650. and there is no evidence of zinc contamination in any of the ingots I poured.

I will melt the rest of it and mix with a coww melt to be used for cannon fodder...it don't care what I feed it... 1/2 lb. of powder will send most anything downrange with authority. The problem with that thing is using something substantial enough to withstand the muzzle energy after leaving the muzzle without coming apart
 
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