Boolit trouble

[fatelk]

I'm not a newbie, really, but sometimes I feel like it. I hope you all don't laugh at me if this is something basic. I've actually cast many hundreds of pounds over the years, but there is still an awful lot I don't know, or have just forgotten about casting. Some of you all I'm sure have forgotten more than I've ever learned.

I just cast a bunch of boolits with my fancy new Accurate mold. I'm happy with the mold; the workmanship is impressive. The ones that come out good are great, but I have to inspect and reject about 10% for problems like the photo.

I'm casting at about 700 degrees, using an alloy of about 50+% "COWW", 50-% SOWW, with a few ounces of extra solder for tin (20lb pot). The "COWW" is a bit of a mystery metal because I bought it as WW metal in ingots, but the ingots have a bit of an aluminum look to them that is suspicious. I've used it before, though, and don't remember this problem.

My Lee pot has developed a problem with the spout. The screws that the lever slides on have stripped out and I just haven't fixed it yet, so the pour stream is inconsistent and I have to hold it just so to make it work.

The other possible issue is flux. We moved recently and a lot of my stuff is still in boxes so I don't have any sawdust that I usually use, have just been using beeswax.

Fire away- let me know what silly beginner mistake I'm making. Thanks! :)

71674

[44man]

Mixing in stick on weights. Many are zinc.
Set the pot to 600* and scoop off all the surface crud. Do NOT flux at that time. Get rid of the oatmeal looking stuff.

[GP100man]

Looks as if the mold may be getting too hot & cooking the tin in the alloy to the point voids happen .

Either slow the pace or as 44man suggested turn the heat down , but turn it down in 5degree increments.

I use NOE molds (aluminum) & find I have to keep the alloy hot & let mold cool a 5 count between pours .

Here`s a pic of some boolits that were poured seconds apart in a steel mold ( I poured the same each time never alternating & that hole was hotter than the other)

http://i746.photobucket.com/albums/xx110/GP100man/102_0417.jpg (http://s746.photobucket.com/user/GP100man/media/102_0417.jpg.html)

[williamwaco]

Some of those look perfect to me.

Top right: I vote mold too cold.
Second from right: maybe same reason but I suspect it was an uneven pour, maybe splashing in the cavity.
There and four from right: Those rounded driving bands are usually caused by severe frosting but the lighting doesn't permit me to judge if they are frosted.
They can also be caused by either metal or mold being too cold but when everything is too cold you should have wrinkles too. I don't see any wrinkles.

Check this series of photos of a mold coming up to temperature from room temperature to perfect cast.

http://www.reloadingtips.com/how_to/mold_warmup.htm

[fatelk]

I put a couple good ones in the photo just for contrast. I really didn't suspect zinc, since about 90% of them are perfect (really nice bullets). No wrinkles at all, in any of them. The lower left one is what most look like.

I wonder about splashing; that could be it, maybe? Like I mentioned, with my pot the way it is the pour is very inconsistent.

The bullets are not frosted, but there is frosting in the voids.

I never had problems in the past with hot molds, so that's an issue i don't know much about. I'll try casting a little slower and see what it does. I have always just watched how fast the sprue cooled, and molten bases, but that was with Lee molds. This Accurate mold uses bigger blocks, and it seemed like I could go as fast as I physically could without it overheating.

[winelover]

Ten percent rejects isn't all that bad when using "mystery metal". That, combined with a botched up spout, I have to say your doing great. I'd take care of the spout issue first!

Winelover

[cbrick]

Mixing in stick on weights. Many are zinc.
Set the pot to 600* and scoop off all the surface crud. Do NOT flux at that time. Get rid of the oatmeal looking stuff.

If it's a silvery looking oatmeal it isn't zinc it's antimony and you don't want to remove it. Scooping it off at 600 degrees before the Sb is at liquidus will cause the silvery oatmeal lumpiness on top of the melt.

Looking at the pics I would say the mold is too cool and the alloy needs to be fluxed. Wax will NOT flux. Wax will do nothing to CLEAN the alloy.

Rick

[44man]

If tin is in the right proportions I don't think antimony will come out of alloy.
Somehow I got zinc into my one batch of pure lead and ingots are mixed so I need to start at 600* and remove the zinc first. It is a gray color and is like oatmeal.
I have been making firing pins for a few revolvers. A friends guns failed to fire and pins were worn short. I harden and then turn my lead pot to 550* to temper. The WW metal has nothing floating on the surface right at the melt point, it is clean and shiny. I have never seen antimony float out.
Zinc needs fluxed to mix back in. The junk really does come out of alloy.
Long ago I did have a batch of WW's with zinc, removed it and the rest made good boolits at the same BHN as the other batches. I do not fear skimming the junk off.
I fluxed one time and had galvanized rain gutter boolits.
Wax WILL flux when stirred through the metal, it is still the carbon. Get zinc on the surface and add wax, stir and see the zinc go away. I have used paraffin forever.

[243winxb]

Maximum heat till the bullets get frosted. Fast cast. (most problems are fixed by using more heat and/or adding linotype.) IMO.:D Added : Maximum heat from a Lee 10 lb pot.

[41 mag fan]

My Accurate molds, I have to slow down when I get them up to temp. Pots at 700*. I'll cast maybe 2 sets, stop, leave mold open for a count of 15 to 20, then cast again. Sometimes I let it not go long enough, I'll only cast 1 then cool. It's all in my cadence, but it seems to work for me.

[cbrick]

Wax WILL flux when stirred through the metal, it is still the carbon. Get zinc on the surface and add wax, stir and see the zinc go away. I have used paraffin forever.

No, incorrect. You have a misunderstanding of what FLUXING is. Wax WILL reduce Sn and/or Sb but it will not, cannot remove impurities (without a magic wand and they are really expensive :mrgreen:) you simply cannot change the metallurgy, chemistry of Pb/Sb/Sn alloys. Wax is not FLUX, it is a reducing agent only.


Maximum heat till the bullets get frosted. Fast cast. (most problems are fixed by using more heat and/or adding linotype.) IMO.:D

:shock: :shock: :shock:

You have no understanding of PB/Sn alloy or what Sn does and does not do when heated past 750 degrees. That's not advice that should be passed on to those new to casting and trying to learn the metallurgy of casting.

Rick

[runfiverun]

I think it has to do with the pour from the pot too.
you don't have any consistency and are probably jiggling the mold around trying to hold your tongue just so while balancing the pour handle with the other hand.
the one big goober is just some gunk got poured along with the alloy.
if the pour handle is buggered up I would suggest a wood/dry wall/machine screw in the spout and a ladle until you can get a new pot.

[fatelk]

Funny stuff. I just made a few more, and I'm more inclined now to think it's something slightly askew with the alloy. I tinkered with the spout handle a little and got it working better. The pot itself is perfectly fine and the handle totally fixable.

I stirred and fluxed good with charcoal, and made some good bullets. I tried cooler and hotter, pot and mold. The biggest trouble I had this time was with fill-out of the base. I dumped a bunch right out of the mold into the sprue pile because I could see the bases were not filled out. Of the hundred or so that made it into the good pile, I only found one imperfect one.

I had to get a pretty good stream into the mold to get good fillout. Pouring from a ladle absolutely did not work at all, no matter how I tried- poor fill-out. Interestingly enough, pressure casting seemed to work well, but I tried it at the very last.

I put all the sprue back in and let it melt, then watched closely as it came up to temp. At one point I skimmed off some lumpy stuff on top, very silvery and hard. In fact the ingots all have a very silver, aluminum shine to them. It's not shiny like linotype; aluminum is the only thing I can compare it to.

I think I'll just fix my pot, then water this alloy down and use it up.71751717537175471752