Strange casting event

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Last Post 12 hours ago

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John Alexander posted this yesterday

I have been casting bullets for quire a while, but recently starting seeing something I have never seen before. It also seems to ignore the. principles of fluid mechanics.

While casting from a pot theat has recently fluxed and skimmed. A small solid looking like ash has appeared floating high on the sprue. It seems to be exactly above the hole in the sprue cutter. These appear intermittently and sometimes stop appearing all together.

It doesn't seem to affect bullet quality or lead to inclusions in the bullet that I have found. Have any of you observed such a floater?

If so have you figured out how an apparently very light solid (it floats high on the sprue) get into the very bottom of the pot and goes through the bottom vent.

John

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CBA Member

Aaron posted this yesterday

Is it simply frosting?

With rifle in hand, I confidently go forth into the darkness.

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CBA Member

delmarskid posted this yesterday

Does it appear to be rising in the sprue as it cools or is it forming at the top? I have never seen this.

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Wilderness posted this yesterday

John

I think you are seeing why some of us have given up on bottom pour pots. "Clean metal from the bottom of the melt" is a myth.

I started with open top pots and went to a Lee bottom pour believing that this would keep the pour well away from the crud. In fact, the crud seems quite happily to form up around the bottom of the pot and in the pouring spout, to the point of needing to be cleaned out periodically. I would also find bits of dross on the surface of some bullets. This is the same as all that oxidation that forms around the pot and has to be scraped loose when fluxing.

I think what you're seeing is some of this crud breaking away from the area of the spout and joining the stream flow into the mould, then floating. It might be breaking away as the valve is closed.

When my Lee pot eventually died I quite happily returned to an open pot, dipping from a cleared clean area on the surface of the melt.

You are only as good as your library.

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trapdoor4570 posted this yesterday

Have seen this occasionally over the years. When it happens I cast the melt into ingots and let the pot cool. When cold, if you pull the remaining lead off the floor of the melting pot, I find a good deal of crud / ash sticking to the floor. A good scrubbing with a wire brush cleans it up. Only to reappear months later. I know it doesn’t make sense, you would think it would float to the top. What I will do most of the time before I cast is that I have a flat bottomed scraper and run it all over the floor. It is surprising how much ash will float to the top.