Better Shake-Out with Carbon Additives

Shake-out is where castings are separated from their moulds. Sand that sticks to castings slows production and increases cleaning costs.

Why sand sticks

Metal penetration, sintered sand and burnt-on clay cause sand to adhere.

How gilsonite helps

The lustrous carbon layer acts as a release film. Gas pressure from volatile matter also helps keep sand away from the metal surface.

Other factors

• Correct clay and moisture levels
• Adequate cooling time before shake-out
• Proper sand system temperature

Results

Faster shake-out, cleaner castings and less wear on blasting equipment.

Signs of poor shake-out

• Sand lumps stuck in cavities
• Long blasting times
• Damaged castings from extra knocking

Contributing factors

Practical advice

Keep carbon additive levels stable and avoid letting castings cool too long in the mould where sand can sinter.

See foundry grade gilsonite. Related: green sand casting guide.