Gold and purple and blue... Oh My!

[sagacious]

Great thread. I did the same thing with WW's today. I did not reduce the temp as I was casting the ingots. I kept noticing this gold that would then turn purple/blue. I am hoping that I can try to heat it up again very slowly because when I noticed the colors I had my pot on 10(high).

So if I let it cool, heat back up very slowly, and I notice just gold color then this means I am okay to go? Should I flux again? Seemed like no matter how many times I fluxed I could not remove the blue/purple stuff.

Fluxing again won't hurt anything, and usually helps something.

Heating fast or slow won't make a difference. You may not need to have your pot temp set on 10 when pouring. There are a lot of variables in the temp setting, such as ambient temp, air draft, how fast you cast, how large a sprue puddle you pour, and if you place the cut sprues back into the pot immediately, etc, etc. You should pour at the lowest setting that will consistently give you good results with the alloy and mold you're using. Try a lower temp setting and get back to us.

Btw, how are your casting results? That's what really matters.

[sagacious]

I didn't get that worded right , I mean't that I had to upend the pro-melt and dump it out, not that i had to turn the heat up.
I still have some of that junk. I'd send a chunk of it to someone if they can tell me what it is. I bought it at a pawn shop , advertised as pewter. It is much heavier than aluminum, and is about the color of aluminum

It could easily be one of the various zinc alloys. That would certainly gum up your works real fast! Pawn shops are not likely to worry about metallurgical accuracy when labeling sale items.

Put a few drops of sulphuric acid on your 'faux pewter'. If it bubbles, it almost surely has a fair amount of zinc in it.

Hope this helps, good luck!

[Trinot]

Okay something surely isn't right here. I am getting extremely slow pour rate, then it stopped. I took some pictures. It seems what happens is that it looks like any other lead I have ever casted (silver), then it turns gold, then it turns purple/blue.

[softpoint]

That looks exactly like the junk I got in my alloy! And yep, it won't flow out the bottom pour spout either. I'd almost certainly say you got some of that fake pewter like I did. And if that's the case, you'll probably have to just dump it out or maybe make trotline weights out of it.

[Trinot]

Dang that is mega suck. This is the first time I have tried to make ingots using only WW's. It was a major PITA. Gosh I certainly hope all of the work wasn't for naught but I think it was. The thing is I don't know if there is anything I could have done to prevent this. I also wouldn't doubt if I went to do it again the same thing would happen. Is there any way to avoid this happening ?

The lead goes from silver to gold to purple to blue. I saw several other posts when I searched where people described the same thing and they where told it was just pure lead and not to worry.

[Trinot]

I just went outside to look at it since it cooled down some. Looks to have turned purple. In the last picture check out where I scraped it with a screw driver, looks like underneath the purple layer it is silver in color.

[softpoint]

Pure lead likes to be cast hot, but if you have the same contaminant Ihad in my pot, you can't get it hot enough to thin that stuff where itwill even flow out the bottom spout.
I always sort my WW and pick out any zinc I find, and watch my smelt when I make ingots and any weights that tend to float withou melting are skimmed out quickly. All well and good until I added what I thought was pewter.

[Trinot]

How can you identify zinc? I thought pure lead would melt a lower temp not a higher temp?

Should I go out and crank the pot up to high and see if I can get it to pour?

[docone31]

I would get the metal molten, and with a spoon, dip out the crud. You won't get out all of it, and the rest you can get out with some Kitty Litter thrown on top.
You will have to cast with the pot on full tilt for a while. I do it all the time any way.
With the pot at full tilt, and most of the crud removed, then with a roof boot, melt it and make ingots, then add the ingots to the pot, going through the Kitty Litter. This will make for some intersting boolitts.
Unless you are going to dump the pot, that will make an interesting sight, You will need to remover the crud, thin the remaining melt, then empty the pot through the spout.
If you take a clothes hanger, bend one end at a right angle, with either an hemostat, or needle nose pliers, poke the spout hole open.
An irony, it was something like this that I discovered my zinc ratio. I do add something like the crud you have to my melt. I keep my pot at full tilt, and it works for me.
You will have to get a baseline for something like that though.
Good luck.

[mold maker]

Is there a way to ID good pewter? I read somewhere that old pewter had a different make up, before a date in history. Also are there different pewter markings? I watch yard sales etc, and there are lots of stuff that aren't marked, but looks and feels like pewter.
It should be a great source of tin, but not if we ruin otherwise good lead with it.

[Trinot]

Well I went out and cranked the pot up to as high as it would go. It will not pour at all. A tiny amount dripped out but only a couple of drops (so it isn't completely clogged). Here are a bunch more pics maybe it will help in leading to ID exactly what the problem is and maybe someone can tell me how to fix it or avoid it in the future. I am not opposed to dumping this stuff out if it is indeed no good. The following pictures where taken in the order posted.

[Trinot]

[softpoint]

Real pewter IS a good source of tin. I think Trinot has the exact same stuff that I had in his mix. My advice; dump it.
Maybe the acid test or something to tell if you are getting real or fake pewter.?
Darn stuff is kinda purdy, ain't it!

[docone31]

Wow!
That is some real nasty crap!
I would get the pot down to almost nothing, then fill it with pure lead. You will unclog the nozzle with a paper clip.
What the heck was that stuff?
I had some mystery metal that raised holy heck in the pot. I had to toss it, mix it with pure lead, then add some Kitty Litter. The Kitty Litter pulled a lot of stuff out.
That is some interesting stuff!
Mystery metal indeed!

[sagacious]

#1) That's way too hot! Turn the temp down.
#2) Flux the melt-- thoroughly!
#3) Scrape the sides of the pot.
#4) Skim off the dross.
#5) Dip out the lead and pour ingots.
#6) Clean the valve stem and spout thoroughly.
#7) Melt the ingots, flux again, and pour as usual.
#8) Do not melt down scrap wheel weights is a bottom pour pot.

The sides and top of your melt is covered with oxide dross. That will get into the pour spout! Never melt down scrap lead or ww's in a bottom pour pot. From the looks of it, I think your pour spout is likely clogged.

I'll sound like a broken record if I keep saying this, but those colors indicate only one thing: that there's lead in your alloy. The oxidation colors are not diagnostic of anything other than the presence of lead at fairly high temp. Nothing more. It is not true that shiny lead = "clean" lead, and blue lead = "contaminated" lead. That belief is incorrect.

Hope this helps, good luck.

[docone31]

When you said blue, there is a blue that lead turns. It is NOT that blue.
That is some serious crud.
I would save it though. Might make a good filler down the road.
If you can find a ratio that works.
With the Lee Pot, if you have a dripper, just turn the spout several turns before shutting down. I use lapping compound on my spout, then add lead.
I have had a Lee pot for several years now. I have not been too friendly with it. It still does not leak. I turn the spout each time I shut down.
I have clogged the spout with zinc. I use a paper clip to unclog the spout. You have to have a column of clean metal to at least thin out the crud metal.
You have your hands full. That is for sure.

[sagacious]

I melt down about 2500lbs of ww's every year. When overheated, they turn exactly that same color, and the melt forms a lumpy dross before fluxing. I don't see the mystery.

Since ww's are being melted here, there is no reason to assume that some totally-unknown and nefarious mystery is happening. That's exactly what (clip on) ww alloy does when overheated.

The melt in the photos should be fluxed, skimmed, and the temp reduced. That will reliably solve the mystery.

I could say, "Oh my gosh! That's crazy! Your metal is CONTAMINATED for sure... I've never seen that before!" But the truth is that I've seen that countless times before. Proceed as advised above, and the mysteries will vanish. Good luck.

[Trinot]

This was melted and made into ingots before I put it in the lee pot. It was my first time melting WW"s, and I must say I should have done my research first. I think I melted other metals in with my lead, possibly zinc and who knows what else. Certainly a learning experience. Next time I am going to melt the WW's much much much slower. I am sad I ever put this gunk into my nice clean lee pot. I don't think that heating this up slowly and fluxing will fix it, I tried that. I heated it up barely to the point of melting and fluxed and the problem persists. I guess this means that all the other ingots I made are no good as well? I saw the blue stuff happening right away when I melted the lead in my ingot pot. I thought it was just oil or something but it seemed that no matter how much skimming and fluxing I did I just couldn't get rid of it.

Tomorrow I will try one more time to do what you said. I will melt it at the lowest setting I know of that my pot will melt lead. When everything is good and melted I will flux and skim. I already did this once today though. You don't think that my problems could have been caused by zinc melting and not temperature do you?

[sagacious]

Trinot,
I think there's a way through this. Keep a little faith, and I just might be able to help you with your situation. Don't worry about not having done your homework first-- we can do this as
"on the job training" too.

First, the coloration isn't indicative of zinc contamination. Were that the case, any number of people would scour the internet for published material suggesting that the gold/blue/purple is a sure sign of zinc contamination, and they would quickly post that evidence here. Not likely to happen, as the oxide coloration is not diagnostic of anything but the presence of lead at high temps. Several people have already confirmed that conclusion here, based on their own experiences.

But OK, let's examine the issue even a bit further, and see if we can do better than just my sole opinion on the matter. What about the clumpy dross? That's gotta be indicative of a problem. Well, not so fast. In this case, if you're melting ww alloy, which is largely an alloy of lead and a few percent antimony, what can we expect from that alloy? At the LASC website, there is an excellent article written by Rick Kelter called Cast Bullet Alloys & Alloy Maintenance. This is fantastic, as it gets straight to the heart of the issue here. From the section on antimony and lead:

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.

Bingo! This is exactly what we're looking at in your photos, and this is exactly what I've been saying about that aspect. "Dross" is the crud floating on the top of your molten lead. Lead/antimony alloys (ww alloy) do this naturally. It can be fixed by fluxing, and then skimming the resulting powdery dross, and then maintaining the alloy properly-- keeping it at the proper temp. "Alloy maintenance" is really the proper term, there are a number of different considerations that must be checked, monitored, or addressed on a continual basis while pouring lead. I can't go into them all at this time, so we'll have to whack those moles individually as they pop up. Don't hesitate to ask questions. I would encourage you to read Kelter's article:
http://www.lasc.us/CastBulletAlloy.htm

I can't say if all your ingots are the same-- who knows. We'll cross that bridge when we get to it. Do not think that your lead is "no good" just yet. Please tell me the basics of how you are fluxing, and with what material.

Alright, if you're still with me, bear in mind that, yes, you could have a bunch of zinc in there, but we can NOT at all be sure of that at this point. Since this is your first time dealing with ww alloy, let's take it one step at a time.

Have you poured any bullets with the alloy? Please use a dipper or a large spoon and pour some test bullets. Make sure your mold is hot enough. Go through what I outlined in the posts above, and pour a few bullets and get back to us. Pour them after fluxing, and try a temp maybe a little lower than #10, and see how it goes. We can go the next step at that point.

Good luck, keep me posted.

[Trinot]

I only had the temperature at 10 for the initial melting. Once it started to melt I turned the temperature down to about 5.5 (my normal casting temperature that I used with the lead I have used in past).

I flux with candle wax. I have uncolored unscented candle wax that is used to make candles. I add it and allow to melt then light on fire. I then skim any crud off the top. This is my first experience ever having this oatmeal looking dross though.

I was able to cast a few boolits before the pour spot got clogged up. They look fine other than the deformities I got from it pouring so slow and the boolit not filling the cavity properly.

Here is a picture of the boolits I was able to cast. It is possible that these boolits where okay because I had a small layer of residual good lead from my old batch of lead in the bottom of my pot, I am not sure of that though whatsoever.

Would it be safe to say that if I would have melted the WW's slower thus not achieving such a high temperature my problems would have been avoided? I am pretty sure it got to hot because it was melted and I thought it wasn't because there where so many clips/junk on top that I couldn't see the underneath had melted. Once you have lead to hot is that just it, its done? I am pretty sure it didn't get too hot in my lee pot because I have a really good feel for it, turn it on high to melt and then turn it down right as it starts to go liquid and let it finish up at that temperature.