What is this stuff???

[chuebner]

What am I getting here? This tinsel like stuff keeps showing up despite repeated fluxing and is driving me nuts. Current picture shows what my melt looks like five minutes after fluxing. Pot temp is 750F. All ideas greatly appreciated.

Charlie


http://i97.photobucket.com/albums/l210/chuebner/IMGP0546.jpg

[cohutt]

Isitzinc?

[Bent Ramrod]

The more highly alloyed lead mixtures seem to generate that silver scum, the more tin and antimony in the lead the quicker and thicker it forms. I wouldn't run the heat any higher than it takes to get well-filled-out castings. I generally push the scum away from one side of the pot with the ladle and fill the ladle with the clear shiny metal that momentarily shows itself. I do this until the buildup gets unmanageable, then I flux. Most of that scum then goes back into the alloy and starts coming out again as the ladling and casting continues.

You may be able to get a lot of it back into the melt for longer times by adding purer lead, like .22 bullets or the cores of jacketed bullets to your mixture. Of course, the downside of this is that with enough addition, the melting temperature goes up and then the oxide begins to build up on the surface at the rates that the silver scum used to. All fluxing does with oxidation is remove it, and the surface begins to generate more almost immediately.

[leftiye]

Lookslikezinctome. You almost never get that much crud from uncontaminated alloys, though a little of that shows up when smelting (toward the end without fluxing while pouring ingots).

[GP100man]

youve been zinced bbbaaaddd!!!!
if it wont flux back in you mite as well
try to cast it into fishing weights then tell the fishers you need WW!!
can you skimm it off down to shiney with out it happening again????

GP100man

[chuebner]

So it sounds like I have zinc contamination. I can stir the stuff back into the melt and the crud returns slowly after about 5-10 minutes of casting. I can also skim the crud down to shiney melt but it keeps returning while I cast. Bullets are casting OK with good fill out and size and weight seem OK for the mold I'm using at the time. Any way to get rid of it? I noticed if I keep ladling and pouring from about 3-4" above the pot I can create a real frothy layer on top of the melt which I then slim off. Can I reduce the amount of zinc in the melt by doing this? Or should I try alloying it out by the addition of more pure lead to the mix. Any thoughts appreciated.

Charlie

[BigGun]

Chuebner:
You might try to reduce your melt temp.750deg.sounds very high to me.My melt runs between
600&650deg. I am using 1part linotype and 2 parts ww for my bullet metal.
my 2 cents worth
good luck
Ted Kelley

[garandsrus]

Charlie,

How much alloy do you have like this? If you don't have much, I would probably try to dilute it. I would try a small batch first! No reason to ruin good alloy...

If you do a search on Zinc, you will find a couple posts that talk about how to get rid of it.

John

[leftiye]

Skim it off and s&!%can it! Eventually the melt will clean up. No guarantee you will have any tin or Antimony left, but my linotype ended up being more like stereotype after de - crudding.

[randyrat]

It may be copper did you buy this alloy pre mixed with some Babbit in it. If there is Babbit in the alloy you'll have some scummy nasty stuff floating in it. Babbit has some copper,tin,antimony,lead. Just push it aside and keep making bullets. You said you were casting bullets right? So maybe it's not Zink. I doubt you would get much fillout in your molds if there was Zink involved.

[randyrat]

One more thing with a lot of Babbit in your alloy your temp has to be high or it will be lumpy. It also will have a copper color (slight). If it is Babbit thin it out or your wasting good TIN.

[Bret4207]

Does it cast good boolits or not?

[44man]

Bret says it best!
If it is zinc, boolits will not fill out and they look galvanized like a rain gutter. I find that is the easiest way to see if it is really zinc.
If it IS zinc, turn the pot off until the lead gets solid then turn it back on at the lowest temperature it will just melt, about 600*.
Don't flux or mix. Skim everything off the top and dump it.
If it makes nice boolits then don't worry about the stuff.

[chuebner]

Does it cast good boolits or not?

Thanks to all for your replies. Here is a pic of some bullets I cast yesterday. Fill out is good but weights are heavier than advertised which is no big deal.

Left is Lyman 311413.

Center is Rapine 460-500.

Right is Lyman 311329.

http://i97.photobucket.com/albums/l210/chuebner/IMGP0550.jpg