bottom-pour blues

[tddeangelo]

Casting newbie here, but how does ladling vs bottom pouring affect the presence, or lack thereof, of air bubbles in the mold/finished ball?

I'm sure not disputing anything, as I know diddly squat....just looking to understand a bit better.

Thanks!

[WadePatton]

Just guessing here but I'm of the mind that turbulence can be greater when using a bottom pour as the velocity of the flow can be quite high with pounds of lead pushing down on it.  This could create entrained air or bubbles that don't escape the mould before the lead solidifies around them.

Or something like that.

[smylee grouch]

When I cast, I like to tilt the mold slightly to one side when I start the pour and then right it or square it to finnish the pour. By doing so hope to get rid of some of the air in the cavity through the spru hole. Dont know if this realy helps any but this is the way I do it be it right or wrong.

[dagner]

  it is volume of lead going into the mold .with a dipper you flood the cavity and then keep pour on the sprue keeping everything liquid. when you use bottom pour you get much smaller stream allowing some to set up very quickly .their is where you get the bubbles.
 dag

[Daryl]

My bottom pour pots, a Lyman, a Saeco and Lee, all spewed out lead with great force. I suspect the high speed lead swirrling inside the mould cavities, tended to cause voids, VSaVIS a gentle pour from a ladle does not.  This is theory.

[dagner]

 I agree dyral  the other was the larger  amount that came out of the hole in dipper fill ing cavity faster-then the real trick continue pouring the whole lade over the sprue.keeps thew sprue and metal in mold liquid longer and as metal in mold hardens at bootom it keeps sucking more hot liquid  metal into the void giving a solider cast.
 dag

[docone]

I run my mold hot. Six seconds to freeze on the sprue.
Never had an issue with fill out, or voids.

[Standing Bear]

30+ years w a bottom pour. I don't let the mold touch the spout on my bottom pour. Keep the mold tilted slightly  till full then level for a good puddle. Takes a few seconds for puddle to solidify.  I usually pour ten, lay the mold on top of the pot, flex the arthritis fingers, run the cooled ten over scale and start over. Not a real high production rate but not in a hurry either.

Have to clean the bottom pour periodically. Think I'll get separate pot to clean and make ingots.

[AZshooter]

Been casting with my Lee bottom pour pot for over 35 years.  Started out with casting .54 Lee improved minie's, and have gone on to a variety of roundballs, and other bullets. 

A bottom pour pot doesn't take any special skill to run properly, but you need to flux occasionally, and to clean the valve a few times per year.  I quit using a dipper and cast iron pot over 3 decades ago & never saw any need to return to using it.

I run my molds Hot, and have never had any problems with casting voids or irregularities.