That tumbler has a flat bottom and is not cone shaped. Based on my research it needs this part to work best at additional cost.
Walnut for the abrasive polishing
Corn media for less abrasive.
I think you can toss a blob of many types of metal polish in with the parts, media.
Here's a blurb from a restore thread, check a couple of the posts- https://pinside.com/pinball/forum/topic/theatre-of-tragicrebuilding-a-classic/page/3#post-4996746
+1 for the HF tumbler.
Its what I've been using for years.
corncob media, with whatever liquid chrome polish is on sale that week.
Squeeze a blob into the tumbler with the media, the media and polish will polish it all up for ya!!!
No real measuring. Just "Meh, that looks good enough". If I had to guess, it would be about the same as a spoonful of pudding, if I ate puddding. Thats for one full tumbler load, with maybe 100-150 pieces in the tumbler.
FYI: Never put star posts in the tumbler, unless you want to drive yourself crazy trying to get the media out of the holes.
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