Am I doing something wrong?

[1n5ane]

Hey guys,

A few weeks ago, I traded a some stuff for a few WW muffins. I just got around to using them this weekend and I've run into a few problems. I've never used WW alloy before; all my casting so far has been with melted down airgun pellets and 22lr bullets(from a bullet trap). I am casting lee 1oz slugs if anyone is wondering.

First off, there was always this nasty layer of dull grey metal on top. No matter how much fluxing and skimming, I could never get it shiny and mirror-like. I did not have this problem when using my original alloy.

Secondly, the resultant slugs are very frosty/hazy looking. This is usually indicative of a cold mold but every slug I cast was frosty. My previous casts(using my original alloy) never had this problem, all the slugs for my previous batch came out nice and shiny.

The two on the left are with my original alloy, the two right ones are with the WW alloy:
http://i54.tinypic.com/24qod46.jpg

Lastly, I had noticed that this alloy is very brittle. When the freshly solidified sprue was knocked off and dropped onto a metal pan, it fractured and shattered. I also drop the freshly cast slugs onto several layers of wet paper towels; occasionally, one would get dented simply from dropping onto a paper towel! The 4th slug in the photo above is an example of this.

Here is a closeup of the 4th slug:
http://i53.tinypic.com/v6mavr.jpg

Does anyone know what the heck is going on? I suspect that the WW alloy I was given is probably contaminated with zinc but I don't have any way to test this.

[SciFiJim]

Actually, looking at the casting and the fact that they dent easily on dropping, I think they may have a very high tin content. Tin has a lower melting temp than WW lead or boolit trap lead. If you are casting at the same temp as before, the slugs will still be very soft when you drop them. I have cast solder using a 250gr SWC mold to have 1/2oz sweeteners for my pot. The boolits will often bend and dent when landing on a folded towel. They always frost over as well.

[mooman76]

22's and pellets are close to pure lead. WWs have other alloys and when casting on the hot side that gives you the frost. Light frost doesn't hurt anything. Also when you are dropping off your sprue cuttings and they appear to be brittle and that is normal also. If you had waited a few seconds longer, they would have been harder and not so brittle looking. The nasty gray metal is tin oxidizing. Like Scifijim was saying tin melts at a lower temp. You can turn your temp down some as it just causes the tin to oxidize faster and appear more.

[southpaw]

Try running 2 moulds at the same time. This should help give the mould some time to cool a little and reduce the frosting and dented boolits some. Or lower the temp some or slow down your casting speed.

Both sets of boolits look good other than the dent of course.

Jerry Jr.

[Larry Gibson]

Pellet and .22LR lead is a binary alloy of lead and a little tin, maybe.

WWs are ternary alloy consisting of lead, antimony and tin.

That's the difference and why you are observing different results.

Second it sounds to me like the temp of your WW alloy is way too hot. The condidtions you describe, especially with the frosted bullets and the sprue fracturing/shattering are indicative of a too hot alloy and thus too hot a mould. I suggest getting some tin and adding 2% to the WW alloy and then smelt to 700 - 725 degrees for casting. Are you using an electric pot with a thermostat on it or if using a a gas stove do you have a thermoeter to measure the alloy temp? Once the mould gets to the correct casting temp also and is dropping good bullets maintain a casting tempo that keeps the bullets good without frosting.

Larry Gibson

[runfiverun]

most 22 boolits are 1.5% antimony and are swaged.
and most pellets are straight lead and are also swaged.
you had your melt too hot.
the sprues weren't brittle they just weren't sufficiently cooled and just broke apart.
by the initial description i thought you had some mono or foundry type.
till i read what you had formally used for an alloy, the slugs from the two different alloys are gonna shoot [internally and externally] and behave differently on an animal.

[918v]

I think the dull layer of metal you are seeing in the melt is the tin separating from the melt. Use some saw dust to flux it back into the melt. Your melt will look like a mirror. I also think the reason your bullets are a bit unsightly is because antimonial lead does not cast as nice and pretty as antimonial lead plus tin. Get the tin back into the melt and your bullets will look nice. I cast my WW alloy at 800-850 degrees without problems. My bullets look spectacular with razor sharp bases. Finally, make sure your mold is hot. I run a heat gun over the mold while my lead melts in the pot. My bullets are nice from the first cast to the last.

[DLCTEX]

I'm not sure, but WW alloy may be too hard for casting shotgun slugs unless they are fired in a cylinder bore. They may be too hard to pass through a choke constriction with out damage to the barrel.

[1Shirt]

I would also wonder about slugs cast of anything harder than straight lead and shot thru anything but a cylinder gun?
1Shirt!:coffeecom

[1n5ane]

Thanks for the suggestions.

I'll try lowering the pot temperature next casting session.

BTW, slugs are going through a cylinder bore mossberg 590A1, hardness should not be a problem.

[thehouseproduct]

If you can, I'd save the WW alloy with the tin for handgun or rifle bullets. Use pure lead for the shotgun slugs. I've found that pure lead seems easier to come by than wheel weights.