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.
Farm boy from Illinois, living in the magical Pacific Northwest