I sprayed both my Dave Brown 3-1/2" aluminum spinner and CB/Tatone 3-1/2" plastic spinner with red UltraCote paint and let the spinners sit for five days since UltraCote takes that long to fully cure. I'm currently using the plastic spinner. After numerous contacts with the starter cone, the plastic spinner still looks new without any scratches from the cone. The trick is avoiding slippage between the spinner and the starter cone.
