softening lead by removing alloy, possible?

[flintlocke]

If you were to melt a bunch of WW's in a large pot, and did not flux, did not stir, and frequently skimmed the surface and discarded it from your melt...do you think your end product would significantly be softer?

[JimB..]

Don’t know, I assume that the tin and antimony would work their way to the top, but even so it’d be a lot easier to just pour ingots and trade for pure lead.

[dikman]

Some of the tin might separate out but not the antimony. I agree with JimB.

[facetious]

Thier in a salusion so thy are not going to seperate, what is on top are oxides of tin. When you flux you are getting the tin out of the oxide and back in to the mix.

[JimB..]

Increasing surface area would expose more tin to the air causing it to oxidize. Melt it in a dutch oven, only enough to fill it maybe 1/2” and stir it aggressively with a slotted spoon for 10 min, skim off the oxides, pour an ingot and test the hardness. Repeat but stir for 30 min, see if you’re getting anywhere. If it’s just tin you might.

In the end the propane might cost more than the shipping to swap it.

[lightman]

As a rule, once its alloyed, its alloyed. But like the others have said, repeated melts will get small amounts of tin to the surface as tin oxide. Back in the day when printers used hot type they had a tin rich alloy to add to depleted Linotype. So you do actually loose something.

Also like the others said, you're probably better off buying or trading for what you need.

[NyFirefighter357]

Are you looking for a softer alloy?

[Der Gebirgsjager]

Why not dilute the existing alloy by adding pure lead until you reach the desired softness?

[Dieselhorses]

I usually notice my first few ingots being shinier than the rest, I assume this is because the tin is on top. I have to remind myself to stir occasionally.

[44magLeo]

When you first start pouring ingots your molds are cold. This lets them be shinier. As the molds heat up the ingots don't shine as much. Same happens with boolits.
Leo

[USSR]

Why not dilute the existing alloy by adding pure lead until you reach the desired softness?

Bingo! That is the way it's done.

Don

[country gent]

To remove an agent in an alloy it can take some nasty things to purify. antimony and tin arnt suspended in but become a part of the mix. They actually change the melting point of the material. If just suspended you would have 3 melting points for the 3 agents. If this was the case then what you propose would work. I have read copper sulfate will remove antimony from lead but its smelly to work with and slow.
If you have a hard allow you might be able to swap 1 hard for 1 1/2 soft even, gaining some in the trade.

[kevin c]

IIRC, a member here who has access to XRF equipment, BNE, did an experiment where he repeatedly skimmed the oxide dross from a pot of very hot alloy over an extended time and then analyzed the composition of the alloy left in the pot. It did not change in any significant way.

I don't recall how big the pot was, how much alloy was in it, how hot, nor how long the test was run.

[lightman]

IIRC, a member here who has access to XRF equipment, BNE, did an experiment where he repeatedly skimmed the oxide dross from a pot of very hot alloy over an extended time and then analyzed the composition of the alloy left in the pot. It did not change in any significant way.

I don't recall how big the pot was, how much alloy was in it, how hot, nor how long the test was run.

At the time there was talk of making it a sticky but I'm not sure that they did. But I remember it the same way you do.

[Lefty bullseye shooter]

I melted down a couple years worth of dross and reclaimed the usable lead that was left. Thinking I had a high tin mix i had it analyzed and found that it was almost exactly what my lead mix was. Apparently I was reducing correctly because i was not taking anything "good" out of my lead.

[gwpercle]

No , the only practical way to soften is to add pure soft lead .
Cast it into ingots , add one ingot of COWW to one ingot of soft lead to your pot , you will then have a 50-50 blend of COWW
and Lead , good for most handgun and hunting boolits in a rifle ..
Gary

[garrisonjoe]

I usually notice my first few ingots being shinier than the rest, I assume this is because the tin is on top. I have to remind myself to stir occasionally.

NO, the tin does not come to the top as a separate layer of metal! A very fine coating of (often golden color) tin oxide may come to the surface, but, as noted by the testing mentioned above, that's a VERY small part of the tin in the lead alloy.

So, as also mentioned above, refusing to flux and stir, and holding the liquid alloy for a long period of time - does NOT make soft lead out of the wheel weights!

good luck, garrisonjoe

[Chill Wills]

I melted down a couple years worth of dross and reclaimed the usable lead that was left. Thinking I had a high tin mix i had it analyzed and found that it was almost exactly what my lead mix was. Apparently I was reducing correctly because i was not taking anything "good" out of my lead.

This is the same conclusion I came up with doing basically the same experiment.

For a number of years I cast the same alloy out of a dedicated LEE 20 lb pot. The alloy was 96-2-2 Pb-Sn-Sb. I cast other alloys from other pots but purposely did not mix the dross. In the case of my experiment I would start up the lead pot and when hot enough to cast, I would skim-clean the top with out fluxing. The dross all went into the same container and at the end of the experiment I took about 50 lbs of it and reduced or rendered it well in my big set-up using pine sawdust and my favorite smokey aroma flux, Pinion pine pitch. I worked it well and poured off the liquid alloy into cast iron muffin pans and put the remaining dross in the empty gallon paint can I use for this to be disposed of.
I have a friend out of state that can test (analyze) samples on industrially equipment and returned the following ratio in percent of the rendered skimings; 2.29Sn, 0.38Sb and the remainder Pb.

I found that at the temperature we often cast at, 725F or close, both the lead and tin oxidize in similar proportion. In contrast, the antimony almost did not show up in the tested sample.

[facetious]

" Back in the day when printers used hot type they had a tin rich alloy to add to depleted Linotype. So you do actually loose something."

I'm a retired news paper pressman, I started in 79 three years after thy stoped using lead plates and went to saddles on HOE colormatic letter press's. I never worked with lead put still had to learn about some of it as a AP.

The tin mix you are talking about looked like some of the pic's of pigs that have ben posted with the holes on the end. I don't know how much thy weigh but started thinking about how much lead it took to plate up three press's. Each press held 160 plates , 480 for three press's and each plate weighed 40lb's for 19,200lbs . As a % of that I don't think it was much that thy were adding.

I was told the lead was rotated out to some place that would test it and bring it back to spec.

Some thing to think about is that each press had a plate boy who had to set all the plates by the unit that thy went on for their press. That comes to 6,400lb's he had to set out at the start of his shift and then pick up and send back to be melted at the end of his shift. The old guy's used to tell me that the only one that never got messed with was the plate boy.

[BNE]

At the time there was talk of making it a sticky but I'm not sure that they did. But I remember it the same way you do.

Correct. I heated a 20 pound pot to 900+ F.

Pulled samples off the top over several hours.

They all measured the same. People spend a lot of time fussing and fighting over this with out real data. Just saying.

Tin and Antimony in lead are like sugar in your coffee. It can be separated, but not easily and it won’t happen on its own.

BNE.