Different speeds on Tumbler - ?? And items getting stuck to sides

by Dave
(Perth aus)

Hi!

Thanks for a great blog again. I make silver jewellery and use my tumbler a lot. I have a couple of issues -

1. If I have hand polished an item to mirror finish and then tumble , I lose the mirror finish and get a different kind of shine - mostly with minuscule tiny pores - is it possible that my tumbler is too fast and denting the silver or do I just need to tumble for longer?

2. If I don't keep an eye on the tumbler sometimes pieces get vacuum stuck to the sides, stay there and end up with a sharp edge instead of smooth.

I'm really grateful for your help.
Thanks! Dave

Stacy's Answer:

Hi Dave!

Here's a novella with this one, so make yourself comfortable! I too, use my tumbler a lot, but I've found that some items are better off being polished/finished by other methods like with the use of a flex-shaft or buffing machine. If you've hand-polished pieces to a mirror-shine, which is a time-consuming process, why are you then tumbling them? They sound lovely as is.

If your silver was full of porosity, it would become obvious during the hand-polishing. Holes are one problem and dents another. Items could only get dented if you were tumbling very heavy items with delicate thin ones. Is it possible that you've got tiny metal particles contaminating the tumbler? Ever notice a fine metal residue in the bottom of your tumbler when you dump the contents out? Be sure and empty the contents of the barrel into a strainer and rinse thoroughly. (shot and jewelry) Rinse the barrel too and then re-load. I do this after every tumbling session. If you're simply digging the items from the shot, pouring the dirty water mostly out and then adding more water, the metal residue builds up. I usually only find tiny metal residue/sludge when I've tumbled rough items like newly cut jumprings or discs that get de-burred during the tumbling process.

FYI-If you're tumbling a lot of precious metal, there are special traps for your shop sink pipes, allowing you to recover the fine metal particles for sending to a refinery later. It can really add up!

Yep. I've had thin flat items get stuck to the sides of the barrel. Frustrating that! With rotary-style tumblers, small flat items like thinner gauge discs often get stuck to the rubber barrel or each other. This causes them to get a scratched finish in the center of the disc on one side. Tumbling fewer discs at a time seems to help. I have not had that issue with thicker gauges (too heavy) or 25mm plus in diameter. (these wider items are longer than the curve on the inside of the tumbler barrel so they can't stick) Tumblers seem to have a common speed ...slow. Not enough to draw a g-force inside the barrel. :-) Mine seems to average one rotation per second or so. Rotary style tumbling is supposed to be a gentle process that usually takes a few hours. I think that sometimes in our hurry, we don't allow the items enough tumbling time to get the job done.

There are no easy answers to all the unique and sometimes very common tumbling issues. I love using my tumbler when I can as it frees me up to do other stuff while my jewelry is being polished. However, I've discovered through trial and error that it just can't used for everything. It usually works well for small components, wire jewelry items, small pendants, rings, etc. Larger fabricated pieces, cuffs, bangles, etc. still have to be polished by hand. (sigh) I hope this info helps you with the problems you're having so you can put more time and energy into creating!