Last batch weirdness, what's this purple stuff

[Brassmonkey]

https://imgur.com/a/5ueM3J4

Melted down a bunch of range scrap last week and all went well till the last batch. Felt like I was Endlessly skimming till I started running out of propane. Turned off the burner and gave it one more swipe before it cooled. That's the clean spot in the middle.

Taking a handheld torch to the surface would cause it to shrink and pull the surface layer that's the odd spots on the surface.

I fluxed it 4 times with wax, once I'm ready to deal with this again do I just keep fluxing & skimming?

The pot was quite full and the temp seemed low as it would take time for the surface to brown before the rainbow effects.




The bad: no thermometer.

[TurnipEaterDown]

The "purple stuff" is either an oxidation of an alloying compound, or an artifact of the wax used in fluxing.
You Probably want that compound in the alloy / melt if it is an oxide.

I used to use old candles as flux (my wife made lots of nearly dead candles for a while...).
I went back to commercial flux such as the Frankfort "Clean Cast" (my memory, could be wrong on name) as (1) I found it just worked better, and (2) my cast bullets stopped having "unique" coloring like purple, faint bronze, etc. when I was casting.

This Colorization I noticed would happen when I was casting BP bullets out of old roof flashing I had, so it could be an oxide of lead (though I don't think those are purple), but I think it was more likely an artifact of the wax used as flux.

The waxes do work as flux, and so will sawdust & tar (be outside for that one, haha...), and if your casting goes OK you can use the waxes, but if you don't like what you see then try some commercial flux on the same alloy and see what it does for your "purple haze".

[super6]

I bought 60lbs of mono type a few years ago and melted for ingots, I got that purple color too! I thought it was left over ink as it was type... I also fluxed the dickens out of it and did a bunch of skimming. I looked up the lead calculator to see what the alloys were for mono type and found this, 9% tin, 19% antimony, 72% lead, WOW a whopping amount of antimony! I ran a question on this board and most said the high antimony content would be of a purple color. Hope this helps!

[lancem]

Over the years I have seen the colors of the rainbow and I never thought much of it, it all cast well.

[Dusty Bannister]

https://castboolits.gunloads.com/sho...rple+film+melt

Common observation when alloy is a bit too hot. Many threads on this in the archives.

[Brassmonkey]

If ya can't tell I'm a big noob to to casting, I've read up on safety and do's and don'ts. But haven't read about this. I got 250lbs out of a mess of buckets of range scrap used the same wax (old decorative candles) and same process throughout. After the tenth skim I feared it would never end and all my lead would end up in the slag pot. It's Like skin on a pot of soup that simmered way too long. Just kept coming back.

As for wanting it in the mix if it is alloying compounds if it's on top, how is it in it? I did use sawdust on the first flux of the first two batches but I prefer the wax.

Any downsides to melting outside in the cold? Was about 30*f last night. Just found it odd that this last batch did that. I've got heat shields around the burner that rise above the pot I was using.

Definitely will by getting a thermometer before I melt again.

[TurnipEaterDown]

Thanks on post #5.

I do know that I switched flux years ago, when casting BP bullets to sell, and my color tinting on finished (cooled) bullets went away.
Never associated it myself w/ pot temp, but it could have been, though I seem to remember changing the flux in a casting session and seeing color tint on bullet go away. May be wishful memory creation, as admittedly it was 10+ years ago.

[deltaenterprizes]

Temperature too hot! That is oxidation, lower your temperature!

[Sasquatch-1]

If your range scrap was mostly jacketed bullets that is probably an indication of soft lead. Soft lead generally has a bluish-purple tint and hard lead has a straw color tint. This is just a general indicator. If you are trying to get a specific hardness you should invest in a good hardness tester. I use a Cabine Tree. Easy to use and repeatable results.

[TurnipEaterDown]

Brassmonkey: as an alloy is heated, some of the metals in the alloy will oxidize easier than others at the boundary layer on the top of the melt. Still an alloy, but the oxidizing reaction occurs directly on atomic components. Hopefully this answers your "As for wanting it in the mix if it is alloying compounds if it's on top, how is it in it? "

Downside of doing it in the cold: more heating energy use (propane if a propane burner), and you may not like yourself getting cold. Guaranteed no spills on you garage floor though...

[Brassmonkey]

Oh boy post #5 just cost me an hour lol, thanks!

Here I was worried about too low a temp and it's likely I was too high. Thermometer!

Side shot I found interesting. Would it help to smooth the surface of my melt pot? It's Just a 12" lodge frying pan. The rough surface Seems to trap black grit.

[TurnipEaterDown]

You'll find yourself happier using a pot where the depth is (much) greater than the diameter.
I find something like a 6-8" saucepan works just fine. Much less oxidation.

Try to avoid aluminum pots. Sure, they work, and I have used them, but a corrosion layer forms much easier between the alloy and pot when cooled and sitting put away than with other materials, and aluminum can slowly alloy w/ lead if I remember correctly.
Cheap stamped steel pots (not the non stick stuff) have worked fine for me.

I still use the thrifty equipment I started with almost 30 years ago.
I liked the saucepan & propane burner w/ ladle approach better than the Mr. Drippy Lee that I bought and then gave away. Too many other things take my money to want to get a good purpose built electric casting pot at this point for me.
(Lots of tutorial on here how to fix Mr. Drippy by the way.)

[243winxb]

I like post #9. High percent of pure lead.

[Dusty Bannister]

DO NOT USE ALUMINUM for a smelting pot.

https://castboolits.gunloads.com/sho...ng+pot+failure

[Brassmonkey]

You'll find yourself happier using a pot where the depth is (much) greater than the diameter.
I find something like a 6-8" saucepan works just fine. Much less oxidation.

Try to avoid aluminum pots. Sure, they work, and I have used them, but a corrosion layer forms much easier between the alloy and pot when cooled and sitting put away than with other materials, and aluminum can slowly alloy w/ lead if I remember correctly.
Cheap stamped steel pots (not the non stick stuff) have worked fine for me.

I still use the thrifty equipment I started with almost 30 years ago.
I liked the saucepan & propane burner w/ ladle approach better than the Mr. Drippy Lee that I bought and then gave away. Too many other things take my money to want to get a good purpose built electric casting pot at this point for me.
(Lots of tutorial on here how to fix Mr. Drippy by the way.)

I have a 20# propane tank with the top cut off that I used for the initial melt, which I then poured into the frying pan, the scrap I was melting down was really cruddy recovered from an outdoor range with a slanted steel backstop that dropped bullet mush into a trough. I'd fill the tank to the top add heat and then after stirring and burning pour about an inch of lead into the pan. Leaving 8in of jackets lil rocks and "dirt" in the tank. I've got 6 5gal buckets of that now But it's a mess that can wait for warmer weather

Thanks again for all the replies and info.

[TurnipEaterDown]

DO NOT USE ALUMINUM for a smelting pot.

https://castboolits.gunloads.com/sho...ng+pot+failure

Interesting & Thanks.

I used my aluminum pot w/ a particular alloy in it for about 20 years w/o issue, but was going to replace it as soon as I found a decent steel one because of corrosion that had formed in the current pot. Never looked for any comments on aluminum pots, because it worked just fine. It is a rather thick one though, probably 5/16 inch or so. Cast many thousands of bullets from that pot.

The replacement will hopefully get moved up, and I'll be melting the alloy out of that old pot outside of my garage.

[Rickf1985]

I have a 20# propane tank with the top cut off that I used for the initial melt, which I then poured into the frying pan, the scrap I was melting down was really cruddy recovered from an outdoor range with a slanted steel backstop that dropped bullet mush into a trough. I'd fill the tank to the top add heat and then after stirring and burning pour about an inch of lead into the pan. Leaving 8in of jackets lil rocks and "dirt" in the tank. I've got 6 5gal buckets of that now But it's a mess that can wait for warmer weather

Thanks again for all the replies and info.

I got something similar to this but much cheaper at Tractor Supply and I use it to scoop out all the wheel weight clips and pieces of bullet jackets while still in the big pot and toss them in a can. That way you can clean up your large batch of lead while still in the burner and not have to screw around with multiple pans. Get all the trash out while in the smelter, that is the whole idea of doing it in that big pot. And the color is perfectly normal, leave it alone. One you get to a regular pot with normal temps the color will go away unless it is pure lead. And pure lead just does that, you don't try to get rid of it.

https://www.bedbathandbeyond.com/sto...ue&wmSkipPwa=1

[Geezer in NH]

Pure lead to hot does that.