orange tint processed range scrap

[lmunte]

I have recently started to cast slugs, bullets will come later when mold prices and availability return, (hopefully). I have processed around 400 lbs. of range scrap so far. Today one of my batches had an orangish, almost looks like brass sheen on the surface of the lead. After fluxing with wax the tint becomes more pronounced, it appears to be mostly on the surface but seems to rise slowly if the alloy is left on the fryer.
I tried to remove most of it by skimming and fluxing repeatedly. I use a cast iron skillet on a turkey fryer with aftermarket burner. I have not seen this before. I separated out the ingots I poured from this batch. It seems the alloy is a bit harder when tested as opposed to the rest of the batches I melted today; BHN ~ 13 for the "tinted" ingots and ~ 13 for the remainder. I have not yet tried casting with this batch of alloy yet.
Does anyone have any idea what this might be and if it is a problem? Many thanks in advance...

[pjames32]

I think your alloy temp may be too high. It could be a contaminant too. I've had this before and used the alloy without a problem.

[Rcmaveric]

Its fine. Temp and alloy oxidation can produce colors. Drop the heat and use it.

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[farmbif]

not sure, but frangible bullet alloy I have seen at scrap yard sometimes has a reddish or orange tint to it. frangible are usually some kind of sintered metals.

[The Dar]

A "brass sheen" on the surface could be tin separating from the alloy. You might want to turn the heat down a bit.

[GregLaROCHE]

As others have said, turn down the heat and cast your ingots as soon as possible. Don’t keep cooking the alloy. I always flux with sawdust first a couple of time before using wax. I think it’s more effective removing impurities. The wax is more for keeping your alloy mixed together. Now days I only use it in the casting pot after a bit of sawdust.

[Huskerguy]

I too think you are probably too hot. Turn the heat down, flux with whatever you want - I use saw dust, candles and the best for me is bees wax. Most important is to keep stirring from top to bottom and all around the edges. I suspect your mix is getting hot enough to separate all the different alloys in the lead and that is what you are seeing. Do the best you can to keep those in the mix. For years I kept skimming and skimming thinking it was impurities. Turns out it was not.

[swheeler]

A "brass sheen" on the surface could be tin separating from the alloy. You might want to turn the heat down a bit.

Yep my first thought, turn heat down a bit and reduce it back into alloy with bullet lube, save the tin.

[Winger Ed.]

I melt & cast with whatever Lead I can scrounge.
I heat it up slowly so all the trash has plenty of time to float up, then I pour ingots.
I heat them in the the pot until it 'casts right'.

I do the normal fluxing & stirring.
After that, whatever color of evil spirts come to the top, I don't worry about them since I use a bottom pour pot.

[Carrier]

So what temperature should he be running it at to not get this?

[Huskerguy]

So what temperature should he be running it at to not get this?
Some of it depends on the lead. Pure lead melts around 620 and wheel weights up to around 700 depending on what is in them which is part of the original question.

Try running 800 or a bit lower, 750. I cast around 720 which works for my alloy. It isn't going to be the end of the world if you run 900 degrees. I have an old plumbers pot that is slow but works well, it just doesn't have the BTU of a fryer so it can't get too hot. The tendency is to crank up the heat and make ingots like crazy. You can do that but I like to keep all the added metals intact if I can.

[Dusty Bannister]

Please consider reading the information in the following link. There is some incorrect information that is being presented in this thread that may lead you astray.

http://www.lasc.us/CastBulletAlloy.htm

[Rickf1985]

900 degrees is pushing the edge of the danger zone of the lead gassing! There is absolutely no need to be that hot.

[bruce381]

yeah 750 is max I cast at 700-720 no problems

[kevin c]

Wikipedia has photos of various lead oxides, many of which are red or yellow in color. https://en.m.wikipedia.org/wiki/Lead_oxide

More heat speeds oxidation, and will give you undersized and heavily frosted boolits.

I've read here to find the liquidus temperature of your alloy (the temp where all the metal has transitioned from solid to liquid) and add about 100° as a starting point for casting temp. I typically go a bit higher (720°) with my alloy (95-3-2) since my 8 cav aluminum molds seem to drop the best and most consistent boolits there.

A contaminant is still a possibility, especially if you haven't seen the same problem before processing other lead at the same temperatures.

Sometimes oxides build up on the walls of my pots. Scraping the walls down with the next melt will make them float up to the surface, but they don't come off the walls by themselves.