Gold and purple and blue... Oh My!

[rogn]

Very good thread--could easily be refined into an article!!! Thank you.

[lwknight]

Bismuth is used to alloy low temp fusible links and also found in some pewter.
Also there may be some cadnium and indium as well. These are common in bismuth alloys. Bismuth pure melts at 500 or so degrees but when alloyed with tin and indium it can melt as low as 140 degrees.

[Alex]

All of this sounds like another good excuse to build a PID temperature controller. I'm fabbing mine up right now. Not nearly as cheap as a casting thermometer but I intend to use mine 3 ways. 1) Furnace temp management using a thermocouple: 2) Lube temp management using a flexible Pt100 RTD: and 3) BBQ Smoker temp management also using a Pt100 RTD.

3 birds, 1 stone

Makes it easier to sell to my wife.

Alex

[Big Dave]

As far as the yellow color, I still have a few ingots of pure tin I salvadged years ago from scrap from a job I worked on. they are all pale straw yellow and the melt was only heated enough to melt and pour the scrap into a muffin tin, not nearly as hot as you need for wheel weights.

[Cactus Farmer]

I,too, have some scrap that has that lovely yellow cast to it. I am very stingy about using it for anything that is not a priority project......I get warm fuzzys looking at those yellow tinged beauties.

[lwknight]

That wheatstraw yellow is a sign of high tin content. In contrast to that I have some contaminated ingots that have a deep brownish yellow and do not cast worth a flip. I have no idea what the mystery metal is but I will use it for weights.

[greg1]

I had the same indication with some lead someone gave me. When I melted it down and cast it into ingots, the ingots were kind of blue. I melted it back down and recast the ingots at a lower temperature and the lead was the shiny color soft lead normally turns when cast.

[Tippet]

Sagacious: Excellent info. Thank you for causing your face to shine upon us.
Trinot: Thanks for starting a really good thread. Will you please resize all your pics to no bigger than 600x800?

As far as smelting WW in a bottom pour, I know people say not to do it. But unfortunately I've only got the one pot so I go ahead and do it anyway. Sure is stinky and yes, there's a lot of crud in there. I use sawdust and painters' stir-sticks. Works great for fluxing. I get the melt cleaned up, I pour my ingots, and I don't let the last little bit of alloy through the spout.

When the pot cools off, I clean it out. If you don't let it get too dirty, you won't have any problems. It's a lot of work though, not letting it get too dirty. You have to flux properly, and you have to clean the pot before crud builds up to a critical level. I use a Lee Pro 4-20, which is easily broken down for cleaning. When I'm done cleaning that pot, it's frikken clean.

So I'm here to tell you, using a bottom pour to smelt WW is not a gauranteed spout-clog, as has been said here. But even if there's no gaurantee, I bet anyone here could easily clog their spout that way.

As far as all that funky color: I had the same thing last year when I melted WW for the first time. I was really having a ball. I had a big SS pot on a turkey-fryer burner. I dumped in a bucket of WW, fresh from the tire shop; I habarely cleaned or sorted it. There were probably a few valve stems and rubber caps and other of stuff, and a lot of motor oil. Filthy. I figured it would all either flux out or it would float to the top for easy removal. Actually it did do that, but it was a nasty stinky smoky mistake. Now I clean the stuff first, and sort clip-on from sticky.

Actually I took pics and posted a thread here and got a lot of info back, but nothing like this thread. Here's that thread if anyone's interested: http://castboolits.gunloads.com/showthread.php?t=56824

I quit using that SS pot because for one thing it's too deep, reaching into it even with a long handled ladle was like reaching into an oven. I've still got the ingots I poured that day, cupcakes actually. They are streaked with purple hues. Bet they'll make good boolits.

[JesseCJC]

You guys sure saved me from pulling what is left of my hair out on this one. I had the temp too high because I put too much lead in the pot for the first time. Second session I had less lead and a lower heat and no more rainbow ingots.

Thanks for the sticky!

[lwknight]

I think blue ingots look cool. That way its easy to ID the pure lead too.

[squirrellnuttz]

A buddy and I were casting ingots today. My first time doing wheelweights. Tiger torch+ss stock pot + 2.5 buckets weights. Cool gold color on the first melt, so, too much heat?.

Then buddy is melting up 40 lbs of x ray shield lead, and the first 20 or so look normal, and the last were just the wildest looking things.Really purple, gold, blue. Too cool. Great thread, guys, and just in time. He's a long time caster, but never ran into that before.

Quite a pool of knowledge here, glad I found out about this site. Thanks for all the info again guys.

[sagacious]

A buddy and I were casting ingots today. My first time doing wheelweights. Tiger torch+ss stock pot + 2.5 buckets weights. Cool gold color on the first melt, so, too much heat?

Yes, a little hot, but not a big problem. You will probably want to flux your lead before casting. The colors are oxide, and fluxing will remove/reduce them, and make pouring bullets easier.

Then buddy is melting up 40 lbs of x ray shield lead, and the first 20 or so look normal, and the last were just the wildest looking things.Really purple, gold, blue. Too cool. Great thread, guys, and just in time. He's a long time caster, but never ran into that before.

Sounds like you may not have reduced the heat as your melt volume was reduced in the course of pouring ingots. Blue/purple/gold is common when the heat is way too hot, and one is pouring fairly pure lead.

Lots of folks have never seen the crazy colors... until the heat goes up too high and then they do see 'em! Since they haven't seen the colors before, many people assume that something must be wrong with the lead itself-- it's fine, but overheated. Just lower the heat a bit next time, and flux those ingots before pouring bullets.

Keep up the good work, and good luck!

[mac1911]

tonight I smelted some sheilding lead, thermometer in the pot
lead sheet stated melting @ a 650'F temp reading I cut the heat back. The lead was all melted @ a reading of 640' I cut the heat back a touch more. got a bunch of crud on top of the lead rainbow of colors very light and dusty.
I fluxed with a toilet ring wax chunk, I felt like I could skim the dross off all night?
I poored into muffin pans and skimmed the dross that formed on the top. all looks normal in the ignots. ?????? should I have turned the heat back down again?

GREAT READ, I have been smelting WWs with no issues.

[sagacious]

... all looks normal in the ignots. ?????? should I have turned the heat back down again?

GREAT READ, I have been smelting WWs with no issues.

Soft lead is especially prone to developing the colored oxide. Yes, one could probably skim that thin oxide layer off pure lead all night, but no need to. Your ingot pouring temps seem fine for soft lead. Go a little lower for ww lead-- about 525-550*F.

Ingots should be poured at as low a temp as is conveniently possible, to help reduce oxide formation. Sounds like you're doing OK!

[lwknight]

A lot of folks have never seen the crazy colors because pure lead is kinda hard to come by.
Roofing lead is probably some of the purest scrap you can get and even that has trace antimony in it.

[Ed Gallop]

The search feature is very nice to have. I have been playing with some lead I bought over a year ago and only recently started to cast with it. I kept fluxing to get the purple and other colors off the top but they came right back. I was puzzled because I never had this experience. I ran a hardness test on a cast bullet and it was off the scale soft. Must have been a 5 or so BHN. Didn't realize I had it too hot so will work on it another time and lower the temp. My problem was the molds wouldn't fill out properly. It was mentioned in another post that the cast were great, but mine was not. I couldn't get the wrinkles out no matter what I tried. The lead was the most shinny I have ever seen. Beautiful. Question... If I lower the heat will it make the molds fill out better?

If I can get the wrinkles out, this lead would be great in all my muzzle loaders and black powder revolvers. Ed.

[sagacious]

I couldn't get the wrinkles out no matter what I tried. The lead was the most shinny I have ever seen. Beautiful. Question... If I lower the heat will it make the molds fill out better?

Ed,
Let's assume you're fluxing correctly, and your mold is clean and otherwise OK, and your pouring technique is correct..... but you're still having 'wrinkle' problems with pure lead even at high temp.

Indulge me with this question: Were your pouring problems during warm weather & high humidity, or cold & low humidity?

[Ed Gallop]

It was a beautiful day. Sunny, in the 80s and not humid. After sleeping on the problem I realized that the day before I was trying to cast from another unused batch I bought on Ebay. I not only couldn't get a decent fill, I tested the ingots and bullets for hardness. I believe it is a contaminated batch of what supposed to be soft lead because it ranged from 10 to 14 BHN with a few up to 16 (both bullets and ingots). I have heard that if zinc is mixed with lead it will cause the same results and also cause the molds not to fill properly with other lead, no matter how clean you scrub the molds. Is this true?

I should add that I've cast over three hundred pounds the last 4 years. I would be much more knowledgeable if I had discovered this forum 4 years ago. It is a great source of information from a nice group of knowledgeable people. Ed.

[Ed Gallop]

I spent all morning cleaning the mold and pot. The mold appears clean but the pot may a problem. I tried cleaning with a brass gun cleaning brush on a drill and when that didn't work I attached a super fine steel wool I use for bluing. I heated to the maximum and it was so hot the steel wool was fire glowing hot. Still, the residue remains. Will not buff or scrape off. The pics show how the lead cast into a muffin pan. The one on the right is the pure lead. The one on the left is one of a Lino mix poured a week ago. Notice how the pure lead does not fill out. The below pic is the pot showing some of the residue that I can't remove. Is my pot ruined? Ed.

Added Info: I have researched this forum and discovered how to extract zinc from lead but can't find how to remove hardened lead from the pots. I assume that is my problem.

[sagacious]

Ed,
I read your other post about cleaning your pot and locating a source of clean lead. Normally, I am very suspicious of claims of "zinc contamination." But the photo of your lead pot seems to point very strongly to that conclusion. That photo saves at least a thousand words of typing! Molten zinc will bond very agressively with steel and eventually even eat right through most carbon steels (been there, done that). That appears to be what you've got inside your pot. Yes, some zinc in the mix can cause fill-out problems.

Your pot is almost surely fixable. As another person advised, you might try sandblasting the pot, with a chunk of rubber jammed into the spout recess to protect it. Re-lap the spout and plunger with polishing compound.

I was able to remove some tenacious zinc residue from a pot once by filling it with vinegar and soaking for several days, changing the vinegar twice. The vinegar will react with the zinc, and you can then scrub the zinc/lead residue out easily. That should do it-- just takes time to soak is all. Good luck.