Weird "Skin" on Hot Lead

[phantom22]

I am getting a weird multicolor "skin" on my melted lead. I had this issue yesterday and it seemed to go away with temp control, but today it persists no matter what. It looks like oil on a puddle....that rainbow effect.

I've drossed, fluxed with wax and sawdust until i'm blue in the face.

I can skim it off but it comes back almost as fast as I can scrape it off.

Using the same lead as I was yesterday too.

I have pictures, but i can't upload them from my phone. I might post them later if it helps.

[Dusty Bannister]

What is the alloy temperature? Too hot will result in discolored oxide forming on the melt surface.

[phantom22]

I'm not sure. I'm doing it in a cast iron pan on a gas turkey fryer base. I thought that it was too hot as well, but cooling it with more lead and turning the gas way down didn't seem to make a difference today. I've used this setup in the past with little difficulty.

I had the lead so cool that it was solidifying on the sides a little and was still doing it.

I do think it is temp related though. Why wouldn't any impurity come right to the top all at once.

[slim1836]

I believe pure lead will show the rainbow colors you describe. Also, tin will float on top if the lead gets too hot. Nothing to worry about, don't skim it off as you might be removing the tin.

Slim

[gwpercle]

You are over heating your lead ... just turn the heat down ... those are just oxides forming on the too hot melt ...that's why they keep coming back .
The rainbow colors are your tip-off that the melt is getting too hot ...it's Okay .
Gary

[Sasquatch-1]

Over heating. If a wheat color it is probably a harder alloy. If a bluish color it is probably a softer alloy. If you are getting ready to cast ingots just pour your ingots and re-flux just before bullet casting.

[phantom22]

I think you guys have hit the nail on the head as to the issue I was having. I managed to get the pictures uploaded and they are listed below. The alloy was "pure" lead.
.

[oley55]

Are you smelting or casting with that fryer burner set up? For me turning the burner down enough for proper lead casting temps result in the very lightest of breezes blowing out the flame. Those fryer burners just plain put out too many BTUs for casting (especially with a shallow fry pan).

[Winger Ed.]

That's pretty normal.
Turn the heat down some to minimize it.

[phantom22]

I'm just smelting into ingots for this setup. I have an rcbs temp controlled pot fir when I cast boolits.

Sounds like I just had the heat way too high.

[Carrier]

You have some nice lead when those colours show.

[DanishM1Garand]

I'm not sure. I'm doing it in a cast iron pan on a gas turkey fryer base. I thought that it was too hot as well, but cooling it with more lead and turning the gas way down didn't seem to make a difference today. I've used this setup in the past with little difficulty.

I had the lead so cool that it was solidifying on the sides a little and was still doing it.

I do think it is temp related though. Why wouldn't any impurity come right to the top all at once.

Same here, I used a turkey fryer and had a hard time with too much heat, I found a burner like a turkey frier but lower heat output in a junk store. It was used probably to melt lead for plumbers on cast iron as it had spatters of lead on it. A lead thermometer solved my issues. It also allows me to keep the lead too cool to melt the stray ZINC wheel weight. At 650 degrees F the Zn just floats with the steel.

[Winger Ed.]

At 650 degrees F the Zn just floats with the steel.

I don't use a thermometer, but when I add more or less clean range Lead to my pot,
I don't have it turned up high enough for the occasional Zinc boolit I come across to melt.
They float up and keep their shape.

Yes, some folks are already switching over to casting pure Zinc wheel weights as the Lead ones are drying up.