Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Metal casting involves pouring molten metal into a mold to create a desired shape. The most accessible method for beginners is sand casting, which uses a mixture of sand and a binder to form the mold. This guide focuses on green sand casting (using moist sand), suitable for small-scale projects like jewelry or simple parts.

Important Safety Notes:

Always work in a well-ventilated area; wear protective gear (gloves, goggles, respirator) to avoid burns, fumes, or silica dust.

Melting metal is extremely hot (e.g., aluminum at 1,200°F/650°C)—use proper crucibles and tongs.

Step-by-Step Guide to Creating a Sand Mold

1.Prepare the Pattern: Coat the pattern with release agent. Place it in the drag (bottom flask half) on a flat surface, core side down if applicable.

2.Fill and Pack the Drag: Sieve green sand over the pattern. Fill the flask to the top, then use the rammer to pack it firmly in layers (about 1-inch thick each time). Tap the sides to settle. Overpack slightly to avoid voids.

3.Create Vents and Gates: Insert sprue pin (vertical pour hole) and riser pin (top vent for gases/metal). Add runner/gate channels if needed for complex pours. Remove pins carefully after packing.

4.Apply Parting Dust: Dust talc on the packed sand surface to prevent sticking when separating halves.

5.Assemble the Cope: Place the cope (top flask) over the drag. Align with dowel pins. Fill with sand, pack as in step 2, and add another sprue/riser if required.

6.Separate and Remove Pattern: Gently lift the cope. Remove the pattern from the drag by inverting it. Clean any sand from the pattern cavity.

7.Reassemble and Inspect: Place cope back on drag. Inspect for cracks or misalignments. Add cores (pre-made sand inserts) if the casting has internal features.

8.Pour the Metal: Preheat the mold slightly (optional for better flow). Pour molten metal through the sprue steadily. Let cool completely (hours, depending on size).

9.Break the Mold and Finish: Once cool, separate flasks, break away sand, and cut off sprue/riser. File or grind the casting for smoothness.

Tips for Success

Test Small: Start with low-melt metals like aluminum or pewter to practice.

Moisture Check: Squeeze sand—it should hold shape but crumble easily.

Common Issues: Porosity? Add more vents. Misalignment? Use better flask alignment.

For reusable molds, consider plaster or ceramic shells, but sand is cheapest for one-offs.