Overmolding onto metal inserts is a common practice in injection molding. One method for achieving this is to design the inserts with overhangs, cavities, or a knurled surface that will allow the plastic to grip onto the metal inserts.

Blasting wood can be more challenging than blasting steel because if you’re not careful you can easily blast away too much material. Wood also does not have consistent hardness properties throughout with knots typically being harder than the surrounding wood. Use a lower pressure, i.e. between 20 to 30 PSI, and keep the nozzle about 8 inches away from the material.