Paint Mixer (also works for mixing glue) by stensino on Thingiverse: https://www.thingiverse.com/thing:7309825

Summary:
Paint mixer for your drill. Very sturdy, since it flexes. This means it can be used to mix glues (epoxy, etc.)Print using 15 % infill. Quite large: The mixing part is 145 x 28 mm.  CAD is included so you can rescale it. You can also try the customizer feature built into Thingiverse (if you want to remove the slots, set slot spacing to 0).Link to part in Onshape:Paint Mixer