PL III - Pembuatan Core

Summary

The video demonstrates how to make a casting core using the CO₂ process. Silica sand is mixed with sodium silicate, packed into a mold, and hardened by passing CO₂ through the mixture.

Materials and equipment

• Silica sand
• Sodium silicate
• CO₂ supply, tubing, and hose
• Split PVC pipe (paralon) sized for the core
• Clamp and screwdriver
• Small needle or piece of metal for making gas passages
• Gloves

Procedure

1. Prepare the mold: Use a split PVC pipe sized for the desired core and secure it with a clamp.
2. Wear gloves before handling the materials.
3. Measure the sand: Fill the prepared pipe with silica sand, then weigh the sand.
4. Add sodium silicate: Use about 3–7% of the sand’s weight. The video uses 5%.
5. Mix thoroughly until the sand and sodium silicate are evenly combined.
6. Pack the mixture into the prepared pipe.
7. Make gas passages: Once the mixture is firm enough, make several small holes to let CO₂ pass through the core.
8. Apply CO₂: Connect the hose to the CO₂ supply, check for leaks, and introduce the gas.
9. Allow the core to harden: It may harden in about 5–10 minutes. The video recommends waiting 1–2 hours to help ensure the process has succeeded.

Speakers and sources

• Instructional narrator/presenter: Explains the materials and core-making process; no name is given.
• Background music: Heard during the video.