Experiment

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  • Last Post 09 June 2019
BudHyett posted this 08 June 2019

In the long standing debate between bottom-pour and ladle casting, what of combining these techniques. One advantage of the ladle is hydraulic pressure to fill the mold when turning the mold over to fill and the ladle is tight against the mold. One advantage of the bottom pour pot is increased production.  

I have been experimenting with pressing the mold against the spout to use the hydraulic pressure to fill the mold.

This requires a higher pot temperature keeping the spout warm enough to not freeze when the sprue plate touches it. A cold sprue plate can freeze the spout instantly. 

Technique:

  • Press the mold against the spout
  • Open the spout for a count of "One thousand one, one thousand two"
  • Lower mold and cover sprue hole with molten lead to allow material for draw
  • Move to next sprue hole.

Benefits: 

  • Better fill-out on bands.
  • More consistent weight. 

Observations:

  • The molds required brushing across the mold with a fine bronze brush to assure the mold lines are clear.
  • One mold had fins along the mold halves due to excessive fluid pressure. This developed after fifty or so casts when the mold was very hot. 
  • The mold sprue plate must be tight and parallel to the mold to prevent molten alloy from squirting out and spraying the casting area.

 

Country boy from Illinois, living in the Magical Pacific Northwest

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dbarron posted this 08 June 2019

I've done this in the past with pistol moulds. Never compared with alternate methods.  Did get the finning, but no squirting.  That sounds invigorating.  Might have to try it again with rifle mould.

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Duane Mellenbruch posted this 08 June 2019

I often used this method with a "cranky" mold that was not filling out well.  It often seems to have helped with fill out and after several cycles the pressure filling of that mold cavity no longer was necessary.  If you have problems with flow into the vent lines, roll the castings between two layers of denim and they break off and you have smooth bullets again. 

I had one Saeco mold #221 with a sprue plate with sprue holes smaller than usual.  Incomplete filling of the cavity resulted.   I had to pressure fill every casting.  I obtained a second plate, drilled it a little larger and that resolved the issue. 

If you consistently have too much pressure, lower the melt level to reduce the pressure of the melt flowing into the cavity.  Wear a glove, the lead can spurt any direction but seems to favor the hand.

 

 

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45 2.1 posted this 08 June 2019

Having used RCBS, Lyman, Saeco, Lee and Magma bottom pour pots, these are the things I've noticed:

1. All except the Magma had small outlet holes which produced a lead stream that was smaller and faster then a ladle pour off the sprue plate.

2. The magma had a thicker lead stream, basically equal to a clean ladle pour.

3. All except the Magma were OK for smaller diameter molds and somewhat minimal for larger bullets.

4. The Magma was very good for larger diameter bullets.

5. None of these were really good for larger rifle bullets (fill out and accuracy problems).

Each size mold basically requires a lead flow volume suitable for the cavity size and depth you're using. With ladles you can have that, from the Lyman egg to the larger Rowell bottom pour ladles.

For the bottom pour guys, you can alter the outlet hole size and shape to produce more flow, but you will probably have to alter the stopper pin or make one to fit what you've done.... otherwise you'll have a big drip-o-matic.

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BudHyett posted this 09 June 2019

 45.2.1 - "For the bottom pour guys, you can alter the outlet hole size and shape to produce more flow, but you will probably have to alter the stopper pin or make one to fit what you've done.... otherwise you'll have a big drip-o-matic."

In your experience, can you increase the flow enough by increasing the flow rate?

Country boy from Illinois, living in the Magical Pacific Northwest

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45 2.1 posted this 09 June 2019

 In your experience, can you increase the flow enough by increasing the flow rate?

 

To increase the amount of flow (which is the flow rate....or volume of flow), you have to increase the diameter of the orifice (spout) on the pot. I know several people who have done this with improved results. Whether or not it increases to your expectations might be a trial and error process. I still think a Rowell bottom pour ladle is best for large rifle bullets though.

 

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TRKakaCatWhisperer posted this 09 June 2019

The game is to observe the results of every change you do (or can) make.  There are folks that are successful with either dip or bottom-pour.  I listen to each group and make adjustments in my application of that method.  I ignore the ones that say the "other" method doesn't work -

 

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