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View Full Version : Making my first ingots...How long do I skim?



d_striker
04-02-2009, 05:09 PM
I was making my first batch of ingots today just to see how it goes..I only did about 20 lbs of lead which was mainly old pipe.

I melted it down and skimmed what I'm guessing was the dross. Powdery dirty crap.

So I keep stirring and skimming but it seemed like a skim would constantly form. I fluxed it with some candle wax.

Do I keep skimming?

What color should I be looking for before pouring into ingot molds? Purple or straight silver?

captaint
04-02-2009, 05:27 PM
not only skim, but also keep gently stirring pot - scrape sides & bottom with something wood if you have & flux again. It's good to get the ingots as clean as possible so you have less of that to do later during casting

jdgabbard
04-02-2009, 05:30 PM
Well, make sure you get the dirty looking crud out. Flux with candlewax, sawdust, dried leaves, whatever floats your boat. Then almost immediately you're going to get that skim. When pouring ingots I don't even worry about it unless it gets too thick, at which point you can just move it out of the way with the ladle and get the good stuff underneath. Now when your casting boolits with a ladle, you'll definately want to get it out of the way, and once it starts getting pretty thick you'll want to flux to mix the alloy back into the pot and then skim off whatever is left on top.

Good luck and good casting.

d_striker
04-02-2009, 05:36 PM
I probably fluxed it 3 times...

I just kept getting more crud on top. I was stirring it quite a bit.

The first garbage that I skimmed off was easy to tell that it was dirt.

The stuff that kept forming was a different color. Did I just remove a bunch of tin from my lead?

Here is a picture...It is definitely soft and metallic.

http://i216.photobucket.com/albums/cc138/dominomofo/DSC0011.jpg

rvpilot76
04-02-2009, 08:09 PM
What temp are you smelting at? I hope you don't have zinc somewhere in there. Smelting at the lowest possible temperature will allow a missed zinc weight to float to the top.

Kevin

d_striker
04-02-2009, 08:21 PM
What temp are you smelting at? I hope you don't have zinc somewhere in there. Smelting at the lowest possible temperature will allow a missed zinc weight to float to the top.

Kevin

I don't know as I don't have a thermometer yet. I was using my MSR backpacking stove w/ a 5 qt cast iron dutch oven. I had the setting a little above medium.

I wasn't smelting WW's so I know there wasn't a stray zinc WW in the mix. It was a few old lead pipes, and a mystery chunk of lead.

If there is zinc in the lead, will it rise to the top in the skim?

ETA-I posted this on another site that I frequent and one knowledgeable person thinks that I needed to turn the temp UP. Says that I may have removed some "good" stuff.

mooman76
04-02-2009, 09:24 PM
Sound like you were skimming off the oxidizing lead. The lead will oxidize on top after sitting a little while and you can't really get rid of it because it just returns. You need to just flux it back in. Also the colors you see are what you get when melting pure lead.

docone31
04-02-2009, 09:29 PM
You can, with lead, skim your pot dry...
I usually just push the crud to the side. It seems, when I skim off, more rushes to take its place.
Just push it aside, a lot of it will melt back in.

d_striker
04-02-2009, 10:40 PM
Sound like you were skimming off the oxidizing lead. The lead will oxidize on top after sitting a little while and you can't really get rid of it because it just returns. You need to just flux it back in. Also the colors you see are what you get when melting pure lead.

I think you're absolutely correct on this. I was referred to http://www.lasc.us/CastBulletAlloy.htmby someone else. Some great reading...

The majority of my lead was old pipe.

""Lead Pipe. Seamless pipe made from lead and lead alloys is readily fabricated by extrusion. Because of its corrosion resistance and flexibility, lead pipes finds many uses in the chemical industry and in plumbing and water distribution system. Pipe for these applications is made from either chemical lead or 6% antimonial lead."

furthermore:

" Lead/antimony alloy drosses considerably. As your melt reaches liquidus temperature that silvery, lumpy, oatmeal looking stuff floating on top is antimony. Skimming it off seriously depletes the alloy; it needs to be fluxed back into the melt."

Slow Elk 45/70
04-03-2009, 03:27 AM
D Striker, man that stuff is ugly! I would say your lead pipe is very dirty and yes you need to get that "stuff" out of it, or you just make a bigger mess when casting. Dip it out and set it aside so you can see what is left?? IMHO it looks like garbage, not zinc, but I have been wrong before, I think....

d_striker
04-03-2009, 11:59 AM
D Striker, man that stuff is ugly! I would say your lead pipe is very dirty and yes you need to get that "stuff" out of it, or you just make a bigger mess when casting. Dip it out and set it aside so you can see what is left?? IMHO it looks like garbage, not zinc, but I have been wrong before, I think....

I'm pretty sure it's antimony. Read post above yours.

Bob Krack
04-04-2009, 06:41 AM
Ya might read this horror story at:
http://castboolits.gunloads.com/showthread.php?t=49323

Dangerous scary. Not neccessarily the case, but . . ......

Bob