new alloy... Light cast bullets @ very difficult to cast?


August 13, 2013, 01:18 AM
Summary- 158gr 38 mold used to cast at 161-162gr using ww's, went to scrap yard got what I thought was mostly soft lead and bullets come in at 147gr. even maxd out on temp, difficult to cast and dont freely drop.

well, after six months, I finally sent in my lee six cav .358 158gr tlswc mold to be repaired after snapping the sprue plate bolt while trying to tighten it down. compared to my 230gr tlltc 45 mold, this thing was a major PIA but I didnt know pain in the butt until I went back to casting with it again after a six month hiatus. previously, I casted with this mold using approx 80% clip on ww's and 20% ~pure lead stick on ww's. Recently I took my junked brass and primers(wow, I had 8 pounds of spent primers in just a year) along with steel ww's and clips to the scrap yard to trade for lead. I paid out $30 or $40 and walked away with 80 pounds of lead. I grabbed a few "pan ingots" that weighed ~15lb each. these seemed to be pretty hard lead, a good smack with a cheap pocket knife just put a slight indent in the flat surface. Lots of random lead, but I thought I grabbed about 3/5 harder lead, and about a third dead soft lead.

First thing I noticed while melting down all the lead and casting ingots was that even though the temp was just above melting, once hardened, the lead had a very smooth and uniform frost to it... Ive casted hot bullets and have seen the frost with thick "grains" or "crystals"... this was nothing like that, it was like its powdered lead.

Well, I finally got to casting tonight darn was that frustrating. Using a lee 10lb bottom pour pot and my normal ww lead, I kept that buggar at 6.5-7 and strategically cranked it up to 9 seven or eight castings before I was about to add a 2 lb ingot. Things were just funny with this batch. Without going into extreme detail, here is how my evening went. Pot at full blast 10, mold pretty darn hot. pour out six. sprue hardening was about what ive been used to, but once cut, first pour was rock solid and the last was still very very soft. did these bullets drop freely to make my night easier? NO WAY! Every single bullet stuck to the right side of the mold 100% of the time. When I was running really hot, sometimes half the bullets would knock free with a few hard raps on the mold. I had to push out literally every bullet with my fluxing spoon.

I get back inside and do a quick QC check and I only found 5 bullets that were no go's. The other 875 bullets were not my best, but still certainly shootable with good fill out. averaging out 100 bullet lots, they came in at 147.0gr when they usually come in right at 161 or 162gr...

At first I thought since this batch needed extreme heat, it had a high lead content because pure lead has a significantly higher melting temp than your standard wheel weight pan ingots errr... wrong, these bullets were way way light.

From my understanding, experience, and a quick look on the periodic table, dead soft lead has a higher melting temp and will give heavier than advertised bullets. harder lead with tin and antimony has a significantly lower melting temp and will give you lighter bullets. im lost

whats going on?

Im lost?

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August 13, 2013, 01:37 AM
sounds like you have contaminated your alloy with some zinc by mistake

August 13, 2013, 01:47 AM
that was what I was thinking:scrutiny: as I drove home with these random pan ingots along with three saeco ingots that a knife test that lead me to believe they were dead soft lead.

My understanding was that zinc screwed with surface tension and resulted in poor fill, voids and rounded bottoms. This batch, well admittedly has a great fill out with complete tumble lube groves. with previous batches of ww lead, a bullet here and there would have a slight void in the thin tumble lube groves.

I had to run the pot very hot, with the mold at a normal temp, the spure froze extremely quick for the melt temp...

there would have to be a lot of zinc in the batch to drop the bulllet weight 10%

and yes, ive casted using pure zinc lol.

August 13, 2013, 01:54 AM
what's the actual melt temp of the alloy in question ? There doesn't have to be a significant amount of zinc to screw up an otherwise good batch of alloy. I assume you have smoked your moulds and all of that ? As far as the bullets being lighter, that indicates less (pure) lead in the mix. You may have some oddball babbit mixed in or something with way too much arsenic.

August 13, 2013, 02:01 AM
I couldnt tell you a real temp but i was keeping my lee 10lb bottom pour pot on 9 or 10 most of the time(depending on when I was getting close to dropping in 2# of cold lead) and that was with my pretty slow pour rate... I got 875 bullets in 2.5hr, normally i get 550ish/hr. Typically with ww's, I keep the temp 7 and occasionally crank it up before adding an ingot.

When melting all the lead down, I did know for sure I had some dead soft lead. I had three ~10" long lead cylinders(that I could whittle like a stick) with a 1/3" hole in the center. they were different diameters but I threw them in last, they probably took a good 25 minutes to completely melt in

And yes, I smoked the bejeezus out of the right side of the mold trying to get the bullets to drop. They would drop pretty easily if they were still silver colored on the base, but then again, they would bend and break apart when dropped on a towel lol. They had to be about as soft as apple sauce to drop easily from the mold

August 13, 2013, 08:04 AM
9 or 10 most of the time

Thats REALLY hot. I mean, REALLY REALLY hot. Most of the casting I do is between 4 and 6.

I would crank it way down, and give another try. The temp of your bullets is more than likely why they are breaking on ejection from the mould- unless its a really crappy unfluxed mystery alloy...which it just may be.

It also could be both.

As to the weight ? You might have got a bunch of "xxxx" thats lighter than lead in there.

Do you have a nasty yellow crud in your pot ?

August 13, 2013, 09:37 AM
Is it possible that the thermostat isn't working and your them is lower than anticipated?

Sent from my DROID RAZR using Tapatalk 2

August 13, 2013, 10:02 AM
What is bullet diameter as it dropped from the mould ?

August 13, 2013, 10:21 AM zinc/aluminum bullets. Post 51- :D Looks like my lee mold has succumb to the heat as one of the tumble lube grooves now sags. Aluminum may make lite bullets ?? :confused:

August 13, 2013, 11:20 AM
Blarby- I tried low, I usually start the pot at 7. The sprue froze instantly and always very hard to cut. I practically had to use pliers to get them out. Bullets only bent and broke when I was running hot and cut sprue the instantly upon freezing, very very soft bullets. And no, no unusual crud from fluxing.

Joustin- I don't believe so. Typically I run the pot at 7 and when adding a 2lb cold ingot, it would take a minute to melt. Last night they practically melted away as I dipped them.

243winxb- I couldn't tell you exactly but over .358 and well based off sizing several that I knew were .363 from a previous attempt where the mold didnt close all the way bc a little piece of lead, Id say they are dropping at .360 to .3605 as they usually do. My calipers just ran out of juice.

August 13, 2013, 12:11 PM
I'm gonna jump out on a limb here and say you have an alloy thats giving you results many of us have never seen before.

Honestly, I'd scrap it and start over.

August 13, 2013, 12:51 PM zinc/aluminum bullets. Post 51-
Looks like my lee mold has succumb to the heat as one of the tumble lube grooves now sags.
Aluminum may make lite bullets ??

From my casting experience with zinc bullets I can tell you that if you have over 2% zinc in your WW mix you'll be able to see it. If you stir a well melted pot it will look like oatmeal. Now if you mix Pure lead and Pure Zinc you won't have that problem because after lead soaked up the 2% the rest of the Zinc will float on top of the lead.

If your sure it's zinc use some pure sulfur to remove it. But I would say if you can't see it than it's not enough to be concerning.

August 13, 2013, 12:53 PM
well, the bullets it makes are just fine by my standards, just a major pain to cast with and 10% lighter. my 38 mold has always been a bit sticky but bullets tend to drop pretty freely once the mold is up to temp(well, besides this time)... maybe Ill bust out my 45 mold that never sticks and see if I can work with this alloy.

thompson- I dont believe there is any zinc in the mix, proper mold fill and lack of any "oatmeal" or unusual flux lead me to that.

41 Mag
August 13, 2013, 01:26 PM
Could be you have a goodly amount of some lino or mono in the mix instead of zinc. Either will cast harder and lighter bullets of proper size.

You can always check for zinc with muriatic acid. You can check in some of the drain cleaners you might have sitting under the cubbard for it or if you know someone with a pool. It doesn't have to be 100% to react with the zinc, but the higher the concentration the more if fizzes. Just put a drop on top of a bullet nose or an ingot and if it foams up any at all you know you have SOME zinc.

david bachelder
August 13, 2013, 01:35 PM
I suggest you get a thermometer and eliminate the guess work.

August 13, 2013, 02:59 PM
Well, either you have something weird going on all over the inside of your mould causing those thousands of imperfections- or you have something seriously wrong in that alloy.

That looks like someone tried to swage powdered lead together.

That does not look like a homogenous alloy.

August 13, 2013, 03:12 PM
There is a thread over at cast boolits forum about fluxing with copper sulfate to remove zinc. It would also remove other reactive metals (like calcium and aluminum, and maybe iron.) Wouldn't hurt anything to try.

August 13, 2013, 03:33 PM
Blarby- my bullets always look like that, same as every one else's that I've seen at the range that cast their own. I didnt quench them but after casting I sprayed em down to cool em off quick and then shook em around real good, that's why they are kinda dinged up. They looked more purty before I shook em around vigorously in a plastic tub

41 mag- thanks for the tip, I checked with "safer" muratic acid, supposedly less fumes, only stuff I had on hand, I don't know if lowes carries the good stuff anymore. Regardless, no bubbles were seen after a few minutes of observation. I put some on some known zinc and it fizzled away.

These puppies seem very hard, difficult to size. I've sized some wheel weight way oversize bullets with ease before, I can tell these are significantly harder

August 13, 2013, 03:43 PM
Ahh- it might be that combined with a really good camera shot, combined with my tiny 10" work screen in my casting area.

Pics can be deceptive- I didn't know that you had agitated them, I thought those were as cast.

My apologies.

If you have this outdoors, and are still worried about the alloy not taking, a very serious fluxing might be in order. Used motor oil is great for that.

41 Mag
August 13, 2013, 06:04 PM
I didnt quench them but after casting I sprayed em down to cool em off quick and then shook em around real good,

If you have a goodly amount of SB and/or AS in that alloy and your spritzing them to cool them quick, man o man are they going to harden right up for you. Even so air cooled they will or can still be plenty tough.

You could also have some babbit metal there as well. Really no telling when you get it in ingot form from the scrap dealer unless he has a scanner.

You might check with them and see if they do, that would at least let you know what your dealing with. Since you do regular business there they might give you a sample scan for free. Don't hurt to ask.

Here's a decent writeup on some alloys,
Cast Bullet Alloy (

Also if you haven't read through this one, I highly suggest it as work bench material.

From Ingot to Target: A Cast Bullet Guide for Handgunners (

August 13, 2013, 06:16 PM
thanks for the info 41, maybe ill get to the bottom of this, maybe ill just have to pull my hair out while casting all this up and just deal with it! I didnt really spray em down and I went along, at the end of my casting session, some were still piping hot, most were warm and some were cold. you know how long a pile of freshly cast bullets can stay hot... I just ran some water over them when I was done so I could count/weigh em out right after.

Depending if this stuff is too hard for my use, im sure I could find people that need superhard lead.

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