Why are they dull?

[wyoduster]

Ok two weeks ago I mixed up a pile of lead in my cooker over 300 lbs and poured ingots .. I wanted to mix up a large batch so that from my first to last bollet they'd be the same.. I added tin to the mix so as to get close to 20:1 (I'm shooting BPCR shoots with Sharps rifles) all my ingots poured out a dull silvery finish my last batch,months ago, was shiny ingots.. and I've made a few hundred bollets and they also are a dull silver ,not the shiny look I like to see..
SO MY QUESTION ::: WHY???

[Nocturnal Stumblebutt]

Generally when the ingot mold is cold, the ingots will come out shiny, when the ingot mold is hot, the ingots come out dull. So if you smelted at a higher temp, or because you smelted so much more, the molds got hotter, and your ingots came out with a matte finish, just like frosted boolits out of an overheated mold.

[1Shirt]

Yep, heat/temp is the issue. For ingots, doesn't make much difference anyhow!
1Shirt!

[snuffy]

Well, you didn't say what your base metal was.

Must we assume it was pure lead? Since you added tin to make 20-1 alloy, I have to assume your base metal was pure lead. Unless you KNOW it is pure, it must have some antimony in it as well. The ingots SHOULD be shiny IF the base metal is pure lead.

[Sonnypie]

It's wrecked.
You'll have to send it to me to dispose of it for you.
Free of charge.... of course.

[Calamity Jake]

Have to agree with the above!

A word of caution, if you used that spendly stand to melt 300# at one time your a BRAVE man.
I wouldn't trust it for anything over 70-80#

[blackthorn]

Is that pot Aluminum or Stainless steel??? If it is AL I would most strongly suggest you switch to one made of steel or cast iron! Over time, Aluminum will not stand up to the temperatures we use to smelt lead and when it fails it will be sudden, with no prior warning! You really do not want to have to deal with that!

[geargnasher]

Generally when the ingot mold is cold, the ingots will come out shiny, when the ingot mold is hot, the ingots come out dull. So if you smelted at a higher temp, or because you smelted so much more, the molds got hotter, and your ingots came out with a matte finish, just like frosted boolits out of an overheated mold.

This is true of alloys containing antimony, but usually not the case with binary lead/tin alloy, which tends to be shiny regardless of mould temperature.

There's something other than lead and tin in the mix, probably a tiny bit of antimony or even zinc.

Gear

[wyoduster]

Its a stainless pot I'm cooking in.. Use to use it to make beer, but I use more whiskey and lead than beer anymore... so....
What's in the lead??? couple pounds of wheel weights and the rest was pure lead sheet and rolled lead roofing. and a pile of bad bollits.. oh and 10 lb of shotgun shot.
Yep there was actually 321 lbs in that pot.

[dverna]

The shotgun shot will have 3-6% antimony in it depending on who made it.

[nhrifle]

It's wrecked.
You'll have to send it to me to dispose of it for you.
Free of charge.... of course.

You are a true humanitarian!!!!

[geargnasher]

Its a stainless pot I'm cooking in.. Use to use it to make beer, but I use more whiskey and lead than beer anymore... so....
What's in the lead??? couple pounds of wheel weights and the rest was pure lead sheet and rolled lead roofing. and a pile of bad bollits.. oh and 10 lb of shotgun shot.
Yep there was actually 321 lbs in that pot.

HELLO! Wheel weights and shotgun shot have antimony in them! Hard to say how much you ended up with in your mix, but it doesn't take much to slightly dull the surface with hot moulds. If you cast with cooler moulds (ingot and boolit) the alloy should still should still be shiny though, the "frosting" only occurs at higher heat levels or with high concentrations, like 2% or more, antimony. I doubt you're even at one percent, but roof lead isn't as pure as it used to be, either.

Gear

[floydboy]

I have experienced the same thing. My frosting was due to high temps. My session was interrupted and when I came back and got things going I made sure I was a little cooler. The rest of the ingots from same melt came out bright and shiny. Easy way to tell is remelt some at a lower temp with cool molds and see what comes out. I smelt with wood so temp regulation was a little tricky until I got used to it.

Floyd

[JIMinPHX]

I would not continue to make beer or whiskey in the same pot that I had already used for lead.

From my experience, dull color could be caused by atmosphere, temperature, alloy or impurities in the alloy.

[mdi]

Yep, heat/temp is the issue. For ingots, doesn't make much difference anyhow!
1Shirt!

Yep, +1

[wyoduster]

OK then that answers my question.. Over heat and maybe a little antimony .. But they should all fly downrange.

[prs]

Did you really add 15# of tin to that Duke's mixture?

For BPCR a true 20:1 is a good choice, but your mix wii be a good bit harder with the antimony and arsenic content.

prsprsq

[DLCTEX]

I would also caution you to strengthen the legs on the cooker. 300 lbs. molten lead would be a disaster if spilled. Otherwise good looking setup.

[MBTcustom]

OK then that answers my question.. Over heat and maybe a little antimony .. But they should all fly downrange.

Sorry buddy, but that alloy is ruined. You see, now that you have contaminated it with antimony (dangerous stuff BTW, if you cast with it, your kids will be born naked and illiterate) your boolits will become frosty when your mold gets up to the proper temperature. This inocent looking frosty surface causes the air to drag over the boolit more and you may lose 50-100fps. Not only that, but the boolits will be more affected by thermocline and the Coriolis effect. This will make it near impossible to shoot a perfect group at 500 yards with your cast lead boolits.
However, I have a good buddy that disposes of contaminated material like this, and he would be more than happy to take care of this batch for $.25 per pound + shipping. I think he even takes Paypal..............................OK my BS reserves just ran dry! LOL!
Unless you are trying to recreate perfect black powder cartridge conditions, your alloy is just fine and dandy for shooting, and that little bit of antimony wont hurt a thing.

[wyoduster]

Out of curiosity ... What the he!! is the "Coriolis effect"???

[kweidner]

It is the effect of earths spin on bullet placement. Only super important at long range. I use it in my ballistic calculator when shooting 1000 plus.

[MBTcustom]

No offense duster, I was just kidding around.
Lots of us actually do exactly what you did on purpose in order to boost the hardness of our alloy for high-speed rifle shooting.
actually, the trick is to tune the alloy to your application. Antimony (which is commonly found in bird shot, Linotype, and monotype) is used to make the boolits harder. Also, an anitimonial alloy will harden with age, so you need to let those boolits set for a week or two, if you want the very best consistency out of them (ie, boolits that you cast a month ago, will shoot slightly different than the ones you cast yesterday because they are harder).
In contrast, tin (commonly found in pewter and solder) is used to make the alloy tougher. It does provide a little hardness to the alloy, but not much. The main thing that does is improve the shear strength of the alloy. This helps it hold the rifling as it travels down the barrel, and also, when the boolit connects with a game animal, tin alloy will help keep the boolit together so it will not break apart and lose mass.
The only problem with tin, is that it likes to bond to steel (like solder) so if you get too much in the mix, you are going to have problems with leading.
As a rule of thumb, you want your antimony percentage to trump your tin. I use an alloy that is 92% lead, 4% antimony, 3% tin, and 1% other stuff like copper and trash from WW material.
With certain powders, this is the cats meow, but there are instances where I can drive a softer boolit faster because it matches the powder/lube/caliber/speed better.
Can I tell you what alloy/hardness for what powder? Heck no! I'm still figuring out the whole hardness vs. caliber, speed, and powder thing.
Anyway, sorry for joking around earlier. Maybe this will be more help to you.
Take care.

[wyoduster]

Goodsteel... No Offense was taken.. I like to hear the abuse.. Makes me smile 8-) I'm learning as fast as I can, but fear lack of years left will slow that. I can use all the info even ifs its bad.. :drinks:

[MBTcustom]

Nah, your doin fine.
Thanks to castboolits, we can take a rank newbie and get him up to "expert status" in about 6-12 months.
It took me 15 years to get to a certain point with my casting and reloading.
I have seen guys that started here asking what mold handles are for, surpass my knowledge gleaned over those 15 years in a matter of months.
This is the place to learn, and the good news is that there are certain laws about casting boolits that are solid, and once you memorize them, and understand them, you are 99% of the way there.
Don't sweat it, it's fun, and the knowledge comes fast.

[goofyoldfart]

GoodSteel: Loved your joking AND I learned something new--just what the "coriolis" effect was.