A gyroscopic paint mixer having a rotatable frame with a clamp lock providing automatic transfer from an unclamping to a clamping condition, providing silent operation through the use of one way clutches, the mixer also having a vertical stop apparatus coupled to an access door for stopping and holding the rotatable frame in an upright position, the mixer also having a bail retainer supported by a carriage assembly mounted for rotation on a clamp plate with a cam urging the bail retainer to the side of the frame when the bail retainer is released from the paint container with the paint container in an upright position in the rotatable frame.