I need help!

[idahoron]

I have been casting with lead I got from my Grandpa. Up to now everything has been going great. I needed some more soft lead for my Muzzleloader.
I bought some lead that is supposed to be 99.97% pure. I got it from a Metal company on the web. I started to melt some and I am getting a huge amount of crap off the top. The dross is yellow, blue, and green. The yellow dross is almost clear. The rest is heavy. When I pour bullets this yellow junk is making flaws on the surface of the bullet. I have tried to cook it off and I just get more. Am I doing something wrong? The lead I have melted before never got this much crap off it.
Also the bullets I have poured before with Grandpa's soft lead weigh 385 gr. I have poured some bullets with hard lead and they weigh in the 373 to 376 range. This lead I am having trouble with makes bullets weigh 380. The lead seems soft but I am just confused about the whole thing. Ron

[montana_charlie]

I bought some lead that is supposed to be 99.97% pure. I got it from a Metal company on the web.
Why don't you post a link to the website with the metal you bought?
Then we can look it over to see if there is something that doesn't seem right.
CM

[NVcurmudgeon]

Charlie has good advice. Also, even pure metal can be oxidized and need fluxing and skiming.

[idahoron]

I found out what I needed to do. I heated it HOT and skimmed the junk off This took quite a while! After I got it cleaned up I added the flux (A chunk a little bigger than a pea of solid ALOX) into about 10 pounds of lead. Then I poured the clean lead in to ingots.
Then I put it in my production pot, and heated it hot again. Once I got the pot full I started to pour bullets. I started to get the target weight of 385 gr as long as I kept the dial on the heater at 8.5 and kept the pot full. As I was pouring I had my scale handy. I checked each bullet and about all of them fell in a +- 1 gr of the 385 target. If the lead got too hot they started to weigh more at about 387gr and got a little frosty, so I turned the dial down until I got to 385 again.
When I was ready to quit (after about 200 bullets that I kept) I let the pot get down. As the pot started to empty the bullets got lighter. When they started to drop below 384.5 gr I stopped and put the rest of the lead into ingots.
They look fine and they are the weight I wanted. I wish the lead was not quite so dirty to start with, but after I got it cleaned and at the right temp I got what I wanted. Here is the web page fo the lead. http://www.rotometals.com/
Thanks Ron

[montana_charlie]

I'll bet your Grampa is smiling...

[idahoron]

I wish i could have talked to him He passed away just over a year ago. He probably would have said what you guys did. Clean and flux. Thanks guys. Ron