What does a yellowy tint on bottom of a Lead ingot indicate?

[JimGnitecki]

I am examining and cleaning up the remainder of both the 30 year old wheel weights and the Lead ingot I was recently given. A few of the lead ingot have a sloght yellowy tint on only a portion of the bottom of the ingot.

What might be causing that?

Is there any alloying agent that can appear yuellowy if not fully mixed into the ingot? Or might this be a contaminant introduced from the ingot mould somehow?

ALL the ingot have either a Saeco, or Lyman, or Ohaus lable cast into them, so I know they were cast in actual ingot molds, not some other substitute moulds.

Jim G

 

[troy fairweather]

Sounds like zink

 

[jmorris]

This is a photo of lead/zinc ore.


You want to separate them before you melt them because it’s not that easy to do afterwards.

Lead-zinc ore is separated by what method? - Dasen Mining

The separation methods of lead-zinc ore are the cyanide method and non-cyanide method. Next, Dasen mining will introduce the practical usage and cases of the cyanide method and non-cyanide method.

dasenmining.com

 

[JimGnitecki]

Well, Jmorris's photo would seem to confirm that some of my ingots have Zinc in them. Here is a photo of the 12 ingot I have found (out of a total of 50 ingots) that show the yellow:



So, 25% of my "pure Lead" supply is contaminated with Zinc, probbaly because it was never really pure Lead but rather lead alloy from MODERN wheel weights, many of which DO contain Lead.

You can see also that the AMOUNT of yellow varies from ingot to ingot, which means these were all melted down and poured from different batches of wheelweights.

Note that these yellow areas are all on what would have been the TOP of each ingot when it was poured into its mold. Is it appropriate to assume that the yellow metal ends up on TOP when poured because;
(a) It is lighter than Lead?
(b) Unlike Tin and Antimony, it does not like to "join the matrix", and so floats on top instead?

I am guessing that it is not possible to SAFELY remove this metal from each ingot MECHANICALLY, even though it might be concentrated in a thin layer on top of each poured ingot, because cutting Lead with a power saw would be very hazardous to a person's health.

The melting temperature of Lead is apaprently 621F. I don't know how the Tin and Antimony in a wheel weight alloy would affect that metling temperature. The meting temperature of Zinc is apparently 787F. So, if I were to put these ingots into my Lyman Mag 25 metl furnace, and set the temperature to say 650F, so that the Lead melts but the Zinc does, would the unmelted Zinc then float on top of the Lead (because Zinc weighs less than Lead), and I coudl skim it off?

Jim G

 

[AJC1]

Well, Jmorris's photo would seem to confirm that some of my ingots have Zinc in them. Here is a photo of the 12 ingot I have found (out of a total of 50 ingots) that show the yellow:

View attachment 1171170

So, 25% of my "pure Lead" supply is contaminated with Zinc, probbaly because it was never really pure Lead but rather lead alloy from MODERN wheel weights, many of which DO contain Lead.

You can see also that the AMOUNT of yellow varies from ingot to ingot, which means these were all melted down and poured from different batches of wheelweights.

Note that these yellow areas are all on what would have been the TOP of each ingot when it was poured into its mold. Is it appropriate to assume that the yellow metal ends up on TOP when poured because;
(a) It is lighter than Lead?
(b) Unlike Tin and Antimony, it does not like to "join the matrix", and so floats on top instead?

I am guessing that it is not possible to SAFELY remove this metal from each ingot MECHANICALLY, even though it might be concentrated in a thin layer on top of each poured ingot, because cutting Lead with a power saw would be very hazardous to a person's health.

The melting temperature of Lead is apaprently 621F. I don't know how the Tin and Antimony in a wheel weight alloy would affect that metling temperature. The meting temperature of Zinc is apparently 787F. So, if I were to put these ingots into my Lyman Mag 25 metl furnace, and set the temperature to say 650F, so that the Lead melts but the Zinc does, would the unmelted Zinc then float on top of the Lead (because Zinc weighs less than Lead), and I coudl skim it off?

Jim G

I believe that when alloyed it melts at the same temp like alloyed antimony. No gooder.

 

[Shooterbob]

Melt one down and see if it looks like oatmeal?

 

[reddog81]

I believe that when alloyed it melts at the same temp like alloyed antimony. No gooder.

I’m pretty sure that’s true. Once it’s mixed together it’s one alloy. I think you can buy some sort of sulphur powder to pull the zinc out if needed.

I once tested a cast iron pot of lead heated by wood to see how hot it was by tossing in few zinc weights as I wanted to see if my backyard fire pit could get hot enough to worry about sorting out zinc or if I could just pull them off the top. They disappeared immediately... A small % of zinc won’t really hurt anything. Something like under 2% won’t even be noticed in most cases.

 

[tightgroup tiger]

Will zinc mixed with lead, when cast into bullets, lead up your barrel?

 

[JimGnitecki]

Melt one down and see if it looks like oatmeal?

I think that before it even looks like oatmeal, it'll be affecting the pour rate and consistency coming out of the melt furnace. Even this early in my novice "casting career", I have found that it is very important to keep the pour rate both consistent and lower than the maximum rate that the valve is capable of delivering.

Jim G

 

[JimGnitecki]

just checking: Does anybody think this yellow substance is NOT Zinc, but something else? I cannot imagine what the somethign else might be, but figured I should ask, just in case.

I was initially thinking something else because I had read that Zinc appears as a "bluish silver" metal, but jmorris's photo showed me otherwise.

Jim G

 

[AJC1]

just checking: Does anybody think this yellow substance is NOT Zinc, but something else? I cannot imagine what the somethign else might be, but figured I should ask, just in case.

I was initially thinking something else because I had read that Zinc appears as a "bluish silver" metal, but jmorris's photo showed me otherwise.

Jim G

I had considered sulfer or rust from sitting in a cast iron mold?

 

[JimGnitecki]

I had considered sulfer or rust from sitting in a cast iron mold?

The color looks too yellowy versus brown to be rust I think. Where would the Sulfer come from?

I also looked up the color of Lead Sulfide. It is a dark silvery blue, so seems unlikely in this case.

 

[AJC1]

The color looks too yellowy versus brown to be rust I think. Where would the Sulfer come from?

I also looked up the color of Lead Sulfide. It is a dark silvery blue, so seems unlikely in this case.

Well not a great idea, but something.

 

[Mk-211]

How to remove zinc from a lead ingot?

How can I remove zinc from a lead ingot? Can I bring the temperature up to the temperature lead melts at and scoop off the remaining solid zinc? Seems to me it should work. I've been controlling my own smelting temperatures so I'm not worried about zinc in my ingots. But I've picked up a...

castboolits.gunloads.com

The link is for both using sawdust and sulfur. Follow links in the thread for sulfur, couple in it.

 

[JimGnitecki]

How to remove zinc from a lead ingot?

How can I remove zinc from a lead ingot? Can I bring the temperature up to the temperature lead melts at and scoop off the remaining solid zinc? Seems to me it should work. I've been controlling my own smelting temperatures so I'm not worried about zinc in my ingots. But I've picked up a...

castboolits.gunloads.com

The link is for both using sawdust and sulfur. Follow links in the thread for sulfur, couple in it.

Yeah, I followed the links, but did not like what they said about the fumes that the sulfur generates. Sounds likte the fumes could really harm a person.

It's only 12 lb of alloy ingots that have the zinc in them. For me, sure I hate to lose the 12 lb, but losing them is better than inhaling suplfur fumes.

Jim G

 

[Englishmn]

Try casting with it before you toss it.
If too much zinc will look like oatmeal in the pot.
If it fills out a mold I will send it.

 

[jmorris]

Out of curiosity, IIRC you have a hardness tester correct?

Can you measure and difference between the red spots and blue ones?

 

[GooseGestapo]

Jim, one thing I’ve found that might help with the zinc containing ingots is to slowly heat them in your pot by starting low and as soon as they start melting, start fluxing and aggressively skim the melt and discard it!
It initially appears “frothy” compared to the lead when just below the melting point of zinc when alloyed.
This helped me to make some zinc containing wheel weights ingots I molded “useable”. This was before I figured out it was zinc weights causing it and learned what the zinc weights look like. You’ll loose some lead in the process but it’s a small price to pay the eliminate the zinc.

I see the yellow powder in my pots too. Always figured it was sulfur or something containing sulfur.

 

[tightgroup tiger]

just checking: Does anybody think this yellow substance is NOT Zinc, but something else? I cannot imagine what the somethign else might be, but figured I should ask, just in case.

I was initially thinking something else because I had read that Zinc appears as a "bluish silver" metal, but jmorris's photo showed me otherwise.

Jim G

I wasn't going to mention this because it's a real reach, but it also depends where the lead ingots came from. I started typing it twice then eraced it. Did someone give the ingots to you or did you melt them down yourself from wheel weights?"

The only other thing I can think of is Arsenic. It was added to shot to make it hard and strong, and added to industrial bearing lead for the same reason.
Wheel weights don't have Arsenic in them that I ever heard of.

I can't imagine those lead ingots have that much Arsenic in them to turn them yellow orange, but I have heard of it before from an old railroad mechanic that used to re-pour the axle bearings in freight cars when they were worn out. He used Arsenic to strengthen the lead. He said his pot would turn a yellowy orange from the Arsenic at times.
A little bit goes a long way with this stuff.

https://en.wikipedia.org/wiki/Arsenic scroll down to "other uses"
Quote:

• As much as 2% of produced arsenic is used in lead alloys for lead shot and bullets.[94]

https://en.wikipedia.org/wiki/Arsenic#History

From "Physical Characteristics" from the Wiki article, "The three most common arsenic allotropes are grey, yellow, and black arsenic, with grey being the most common.[15]"

Stay up wind of it and don't lick your fingers after handling the stuff, just in case.

 

[otblue]

Some lead oxides are yellow so it might be as simple as that.
I had a roll of roofing lead that had been sitting outside for 40 + years that had a bit of similar yellow staining and when I finally melted it down into ingots the stuff just came of with the dross.
The metal poured well and filled molds as expected.

 

[Blue68f100]

Could it just be a indicator of a heat band? Metals when heated and cooled have a gradient color band indicating heat. Since this is the side up it was exposed to the O2 to cause the oxidation to give a color. I remember the yellow/gold color on my motorcycle exhaust and yellow was one of the lower temp colors.

 

[JimGnitecki]

Thank-you guys. I appreciate the hl[peful diagnostic and remedial suggesitions. Tightgroup Tiger: I was given these ingots by a friend who got them (plus the other 38 ingot that don't show this yellow color) from one of his buddies. My friend does not know the history of these ingots. He is going to ask his other buddy about these.

jmorris: Good idea on testing the hardness. I am going to a long delayed range session this morning, but should be able to do the hardness testing on ingots 1,5, 11, and 12 later today. If the yellow is truly Zinc, the ingots you marked in red in the photo (5 and 12) should test notably harder than 1 and 11. This assumes that even a thin layer of Zinc on top of underlying Lead will be sufficient to cause the Lee 30-second indentation test process to produce a higher BHN.

GooseGestapo: When you used the "spire" point bullets produced by that Lee aluminum 485g mold (whose casting behaviour is wonderful!):
- What velocity were you firing at?
- Did you track the accuracy at different ranges? (i.e. accuracy at 100 yards, 200, 300, etc?)
I'm asking because for me those bullets worked GREAT at 100 yards, but would not group at all by the time they got to 150 yards.

My planned range testing this morning involves a ladder test at Accurate 5744 powder levels of 21.2g, 21.7g, 25.0g, 26.0g, and 27.0g, all using the Track of the Wolf .460" expander with zero crimp (so the bullet can slide back into the case a bit when it encounters the rfifing during chambering), loaded a few thousandths into the rifling, so that the bullet will be set back slightly into the case when it hits that rifling. I want to see if "zero jump" makes a difference with this bullet in this rifle. I think it might because the spire ogive shape limits the bullet's actual contact area with the rifling, so letting the bullet contact the rifling before launching it might help.

The unusual spread in powder loads in this ladder test (21.2g, 21.7g, 25.0g, 26.0g, and 27.0g) is intended to keep the bullet either as subsonic as possible or as supersonic as load table safety allows. This is because I suspect that the lack of grouping at 150 yards was because the bullet as launched in that earlier testing was smack in the middle of the upper half of the transonic speed zone (about 1150 fps to 1317 fps), which is a bad place to be if a bullet is prone to transonic disturbance. I am thinking that the new powder load levels will keep it in one of two speed ranges, either:

- low in the transonic range (21.2g and 21.7g which grouped the best at 100 meters and grouped at least SOME close to decent groups at 150 meters) where the transonic effects are mitigated versus at higher velocities, or

- in the 1300 to 1400 fps range (25.0g, 26.0g, and 27.0g) where the bullet spin rate will be higher, and thus hopefully make the bullet more resistant to actually wobbling due to transonic disturbances.

If the loading to touching the rifling, coupled with neither of the two speed ranges above works at 150 yards, I will need to give up on that bullet mold, because while a 0.62" 3-shot group capability at 100 yards is nice, I want to shoot this rifle at up to 600 meters = 650 yards at my local range.

Jim G

 

[JimGnitecki]

Could it just be a indicator of a heat band? Metals when heated and cooled have a gradient color band indicating heat. Since this is the side up it was exposed to the O2 to cause the oxidation to give a color. I remember the yellow/gold color on my motorcycle exhaust and yellow was one of the lower temp colors.

I suppose it is possible. The hardness testing that jmorris suggested might shed some light on that.

Jim G

 

[jmorris]

This assumes that even a thin layer of Zinc on top of underlying Lead will be sufficient to cause the Lee 30-second indentation test process to produce a higher BHN.

That’s the unknown. I’d probably flip them over and test the bottom as well.

First thing I’d probably do is just cast a few bullets with them and see what weight they drop at vs known lead. That gives me a better idea of what it consists of than what it looks like in a photo.

I generally saw off a corner and heat it in a ladle with a propane torch, to cast a couple, for expediency.

 

[JimGnitecki]

I made time to take the hardness readings before leaving to go to the range. But the test results are non-definitive for reasons discussed below.

The Lee hardness tester process when done on the 4 ingots (numbers 1,5, 11, and 12 that jmorris suggested) gave exactly the same size indent on all 4 ingots: 1.04 on the Lee pocket microscope scale. The scale only goes from 0 to 1.0, but the indent diameter was clearly at an extrapolated 1.04 on that scale.

The Lee "cheat sheet" that converts the indent diameter to BHN numbers only goes up to a "softness" of 0.79, at which the BHN is already down to 8. So, whatever this yellow color is, it either:
- is not hard enough to affect the hardness of the ingot,
OR
- it is simply too thin a layer to be measured with this test method. This method involves penetrating into the ingot untikl the indent is a standard depth, and then holding the metal punch for 30 seconds at that standard depth. If a larger "peak" force was required to penetrate a surface layer different than the underlying Lead, this test won't reflect the actual hardness of that surface layer, because it does NOT measure the peak "force" required to penetrate the metal, but rather the end DEPTH via measuring the DIAMETER of the resulting hole, because the punch is tapered to provide that.

Jim G