issues while smelting lead and need help/advise

[latesvak]

so im melting down a 5g bucket worth of ww like i have done so many other times . im cooking them down in a c.i. dutch oven (6" tall and 14"wide) over a turkey burner . not my first rodeo doing this by any means . so the first two melts went fine with me getting 12 1.5 lb ingots per pot . previously i had sorted and pulled all but the lead ww vs others. if i think it might not be lead i scratch it on a file to rough it up or i will dent check it with some pliers just to double check. so im pretty sure all the bad ones are out .
well after getting this 3rd pot melted down and getting ready to start skimming the dross off it just looked a bit off to me . then after getting all the clips out i skimmed it off and added some wax then waited for it to burn off then scrape all the sides and bottom as usual. then it got an almost iridescent color to it . like some purple/orange/yellow layer on top. wth is this im thinking? so i skim it off and fluxed again. i tried 2 different waxes and sawdust and this layer of junk kept coming back . any help would be greatly appreciated .

thanks

latesvak

[WileyWilly]

I believe that you have Zinc contamination from the descriptions that I have read. See this thread:

http://www.falfiles.com/forums/printthread.php?threadid=222084

[bumpo628]

It just sounds like the melt got too hot.

http://castboolits.gunloads.com/showthread.php?t=63550

Do you use a thermometer when smelting & casting?
Here's one for $25 delivered: http://kck.com/tel-tru_grill_smoker_thermometer.html

Tel Tru BBQ Smoker / Grill thermometer
This is a 2" BBQ thermometer that is very well made
Green Egg or Kamado thermometer, pan clip, LT225R, 5” stem, 200/1000F, boxed 
BBQ-TT-200-5-200/1000

Zinc contamination should produce an "oatmeal" appearance on the top of the melt, not colors.

[Rock6.3]

The colors are from being too hot.

Zinc would be lumpy and colorful at the same time, not liquid like you are seeing.

No damage done, pour the ingots and use them.

Or ship them to me for proper disposal.

[XDRoX]

Buy a thermometer. It's not good for your health to let the lead get that hot.

[latesvak]

thanks for the answers. i turned it down a bit and that seemed to help and all went smooth after that . ill have to see how they turn out when i cast em up as for the thermometer thing i guess i was just kind of winging it and thought they cost a lot more then that and will now be investing in one. thanks to everyone all for the answers given.


latesvak

[GSwain]

The colors are from being too hot.

Zinc would be lumpy and colorful at the same time, not liquid like you are seeing.

No damage done, pour the ingots and use them.

Or ship them to me for proper disposal.

This exactly. Sawdust makes a better flux than wax too, it reduces tin oxides. You want that tin to stay in and dissolved!

[ireload]

Yep too hot. I purposely did that on a batch of WW once just to see how it looked.