Lead inpurities

[snrub47]

Melted some scrape lead in my casting pot yesterday. Today when I looked it has a dark blue coating on the surface. What can it be?

[D. Taylor Sapergia]

It is not impurities in the lead.  It is lead oxide.  You may have your lead a little too hot for good casting.

[snrub47]

Thanks Taylor......

[D. Taylor Sapergia]

When you are melting your lead, getting ready to cast balls, the surface of the lead does not stay shiney silver for very long...oxide forms on the surface, and will eventually require fluxing and skimming off the dross that accumulates.  If you don't some of the floating oxides will end up inside your balls and create uneven weights and if you use them as is, poor accuracy.  Consistency:  thou art a jewel.

[FDR]

To flux I drop in a pea sized ball of wax (candle, beeswax whatever) and immediately light the fumes with a match. Stir the wax in and when the flames go out skim the dross off with an old spoon. Nice shiny lead remains. Now cast away and repeat the flux and skim process as needed .

Fred

[Daryl]

I find if the temperature is good for pure lead casting (needs to be hotter than alloyed lead), the lead itself will ignite the wax.  If not,
 it smokes quite a lot - so not for indoors without a really good fan.
I used to cast in my basement with a squirrel cage blower above the pot, vented out the window. above the bench and smoke was
never a problem, when using Marvelux, a semi-smokeless fluxing compound.  The squirrel cage was an incredible blower, even though
it was a 220volt unit, it still worked amazingly well on 120V. The only problem with Marvelux, is it makes a coating on the inside of the pot
that can build up over time.  My alloyed metal pot's coating is almost 3/16" thick, all the way around.
Now, I do all my casting outdoors in the car port & when using alloyed lead, the resulting smoke just blows away & everyone else in the
neighbourhood knows what I'm doing - oh well.

[Mad Monk]

Something of an aside here.  The last remaining lead smelter in the U.S. was in Missouri.  That smelter shut down around 2013.  These lead smelters have always been something of an environmental disaster to the areas in which they operated.  So today any "new" lead comes in from other countries.  When communist Russia fell they swamped the world market with their excess lead at low prices.  But now most of the lead is salvaged from other uses.  Until a few years ago I had an Exide battery plant a few miles from the house here.  They salvaged lead from scrap batteries.  Then they would also smelt lead from other salvage operations.  What was going out their smelter stack was kind of scary.  It was too costly to bring the operation up to present day emission standards so they finally shut it down.  BIG improvement in air quality.  So how pure you lead is will depend on who you got it from.  But most of what is out there is salvaged lead these days.

[bob in the woods]

Most of the lead I have , I salvaged 20 and more years ago.  One hundred pound bar from a plumber, plus 3 5 gal pails of sheets from dentists offices, + a wack of divers belt weights, weights from old commercial fishing nets, and finally , lead pipe.  I think I'm set for the rest of my shooting days.

[Daryl]

Taylor and I ended up with several hundred pounds of sheet lead from the local Hospital X-Ray room.  This stuff is so
pure (it seems) I have to add a bit of tin so I can cast 25 balls between fluxing. At a temperature the lead casts well,
it colours up badly, then forms a crust which must be scraped off, then re-fluxed, then cast another 25, etc.  The more
alloyed the lead is, the less of this "effect".
I usually add 1/2" from a 50/50 tin/lead plumber's bar for an 18 (or so) pot of lead and that's it for the entire pot. Casts
well after that & still is dead soft, of course.
We paid $0.50 per pound for the lead.

[Scota4570]

Couple of tips,

Marvel flux will rot your lee melting pot over time. 

To ignite the wax flux keep a few granules of smokeless powder handy.  A single granule of powder will make a tiny spark and light your wax smoke.  I do not like to have it spontaneous ignite while stirring, it makes me flinch. 

[bob in the woods]

Thanks for the tip about Marvelux . I ruined a couple of Lee Melting Pots when using that stuff.  I always wondered why the nozzle plugged up/ got coated so it either would no longer seal or just not flow at all.  That was long ago, but was the reason I changed to a cast iron pot, a dipper and a Coleman stove. Haven't seen any reason to change back

[Dennis Glazener]

Taylor and I ended up with several hundred pounds of sheet lead from the local Hospital X-Ray room.  This stuff is so
pure (it seems) I have to add a bit of tin so I can cast 25 balls between fluxing. At a temperature the lead casts well,
it colours up badly, then forms a crust which must be scraped off, then re-fluxed, then cast another 25, etc.  The more
alloyed the lead is, the less of this "effect".
I usually add 1/2" from a 50/50 tin/lead plumber's bar for an 18 (or so) pot of lead and that's it for the entire pot. Casts
well after that & still is dead soft, of course.⁷
We paid $0.50 per pound for the lead.

Thanks for that info Daryl. I bought about 30 pounds or so of virgin lead that supposed was the last that was mined from a  recently closed lead mine, mid-west I believe it was. Have never had to go into it but will remember this.

[Daryl]

Couple of tips,

Marvel flux will rot your lee melting pot over time. 

To ignite the wax flux keep a few granules of smokeless powder handy.  A single granule of powder will make a tiny spark and light your wax smoke.  I do not like to have it spontaneous ignite while stirring, it makes me flinch.

Interesting about the pot. I am still using the pot I used Marvellux in up until about 4 years ago and it is not rotted that I can tell. The time period I used it, was perhaps over 20 years
and 3 1-pint containers of it.  I also use, from time to time, paraffin or Beeswax when casting outside.  The bowl is coated though that is all that is wrong with it. I plugged both of my Lee
20 pound bottom pour pots with #6 self tapping screws, run in from the top with an impact driver. Worked great. I prefer to dip the balls and bullets - better consistency.
Hadn't thought of the smokeless - yes, that would work.  I used to use a Bick lighter, back when I smoked. That ignited the fumes of the beeswax very well.  The pop of the wax igniting doesn't
seem to bother me - I know it is going to happen, so no surprise.  Sometimes it doesn't ignite and that just means the melt isn't hot enough, yet.

[Mike from OK]

Something of an aside here.  The last remaining lead smelter in the U.S. was in Missouri.  That smelter shut down around 2013.  These lead smelters have always been something of an environmental disaster to the areas in which they operated.  So today any "new" lead comes in from other countries.  When communist Russia fell they swamped the world market with their excess lead at low prices.  But now most of the lead is salvaged from other uses.  Until a few years ago I had an Exide battery plant a few miles from the house here.  They salvaged lead from scrap batteries.  Then they would also smelt lead from other salvage operations.  What was going out their smelter stack was kind of scary.  It was too costly to bring the operation up to present day emission standards so they finally shut it down.  BIG improvement in air quality.  So how pure you lead is will depend on who you got it from.  But most of what is out there is salvaged lead these days.

Is that Doe Run?

I know they still do some type of production there because one of our customers uses lead from there. They use it for the lead sheathing on medium voltage cables used to power high volume down-hole petroleum pumps. But as you said it's probably recycled lead.

It's something to see a trailer back up to the receiving dock door and a forklift unloading 2000 lb ingots... Usually 17 or 18 per trailer load. I've seen upwards of 80,000 lbs of lead stacked up on the floor waiting to go in the furnace... It takes a lot of lead to sheath 3 phase conductors that'll power a pump 17,000 feet underground.

Sure would like to have one or two of those ingots... I bet they get a heck of a discount for bulk ordering. Wonder if they'd order a couple extra for me and let me cut them a check when they show up. Lol

Mike

[Mad Monk]

Something of an aside here.  The last remaining lead smelter in the U.S. was in Missouri.  That smelter shut down around 2013.  These lead smelters have always been something of an environmental disaster to the areas in which they operated.  So today any "new" lead comes in from other countries.  When communist Russia fell they swamped the world market with their excess lead at low prices.  But now most of the lead is salvaged from other uses.  Until a few years ago I had an Exide battery plant a few miles from the house here.  They salvaged lead from scrap batteries.  Then they would also smelt lead from other salvage operations.  What was going out their smelter stack was kind of scary.  It was too costly to bring the operation up to present day emission standards so they finally shut it down.  BIG improvement in air quality.  So how pure you lead is will depend on who you got it from.  But most of what is out there is salvaged lead these days.

Is that Doe Run?

I know they still do some type of production there because one of our customers uses lead from there. They use it for the lead sheathing on medium voltage cables used to power high volume down-hole petroleum pumps. But as you said it's probably recycled lead.

It's something to see a trailer back up to the receiving dock door and a forklift unloading 2000 lb ingots... Usually 17 or 18 per trailer load. I've seen upwards of 80,000 lbs of lead stacked up on the floor waiting to go in the furnace... It takes a lot of lead to sheath 3 phase conductors that'll power a pump 17,000 feet underground.

Sure would like to have one or two of those ingots... I bet they get a heck of a discount for bulk ordering. Wonder if they'd order a couple extra for me and let me cut them a check when they show up. Lol

Mike

Mike,
From what I could find.  The smelter that refined the lead mined on the site was no longer working with freshly mined ore.  So it looks like they went to re-smelting lead picked up off the open market.  The ore smelting smelters were environmental nightmares.  The company could not afford to build a new ore smelter that would comply with the then regulations.

I got into this some years ago when an environmental group started to dig into the Exide Battery Plant outside of Reading in Laureldale.  The wife and I lived about a block away from that plant back in the 1960's.  During damp nights you could not go out of the house and linger for any length of time.  The smelter kicked out large quantities of hydrogen sulfide that joined with the water molecules in the damp air.  The list of heavy metals other than lead that were being vented into the atmosphere was frightening.  After about a year we moved well away from that place.

Then some years later I got a call from some guy who was something of a manager at that facility.  Directed to me by Chuck Dixon.  The guy shot BP.  I had to explain the basics to him on setting up a column on the smelter that would remove most of the sulfur dioxide from the smelter exhaust.  The spray column uses plain old fertilizer lime ground with a bit of soap in the water to suspend the ground lime stone.  When the smelter stack vapors are passed up through the column it is subjected to the lime spray.  The sulfur dioxide contact changes the sulfur dioxide to calcium sulfide.  If not contaminated  with heavy metals it can be used on farm fields. Trouble is that when they operated the stripping column nobody watched it and added lime to replace that which was converted.  They just did not take such things seriously enough and the state finally put them out of business.  And a lot of land down wind from the smelter ended up as Superfund sites.

[Mike from OK]

Interesting stuff Bill, thank you.

If you're interested in superfund sites, look up Tar Creek. It's a former lead/zinc mining operation about 30 miles from me... At one time it was considered the largest superfund in the US. It may still be. I don't know if they'll ever get that one cleaned up.

Mike

[snrub47]

My lead pot...never had this happen before....

[Daryl]

That's been sitting for a while, I assume.
Skim the dross off and see how long it takes to re-colour up.
Mine did this and as I noted, I had to add 1/2" of 50/50 solder to the 20 pound pot, likely 18
pounds of metal.
After that I could cast 25 balls, then skim, another 25 balls, etc, etc. There was a lot of oxidation going
on with my lead.
That is, this should work, unless you have something else going on???
That is quite a mess you have going on. I thought I was messy.

[Mad Monk]

Interesting stuff Bill, thank you.

If you're interested in superfund sites, look up Tar Creek. It's a former lead/zinc mining operation about 30 miles from me... At one time it was considered the largest superfund in the US. It may still be. I don't know if they'll ever get that one cleaned up.

Mike

Mike,

I live close to the old New Jersey Zinc mine and smelter that once operated at Palmerton, PA  North of Allentown, Pa.  Ran from 1898 until 1980.  A big long slag pile full of nasty heavy metals.  When you come into the valley up there you are suddenly looking at 2,000 acres of no vegatation.  The North side of the Blue Mountain wouldn't even grow grass.  Slowly they have been remediating by filling good dirt over the bad dirt.  The mine was originally a town called Friedensville.  But that town was long ago buried in mine tailings.  Something of a duplicate of the one you mention.