This is my affordable rock tumbler, designed to tumble 3D printed parts, printed in ColorFabbs metal filled filaments (BronzeFill, BrassFill, CopperFill).
It is
...さらに表示 also possible to add a 'golden' shine to regular PLA when the parts are tumbled with brass screws.
It should be possible to build this tumbler for less than € 40.- which makes it much more affordable than 'professional' tumblers that can do nothing better than this one ;-)
Please find the full instructions including the BOM here: http://www.instructables.com/id/Affordable-Rock-Tumbler