Tumbling Nightmare

Hi all,

I posted on here last week some time asking for advice about whether or not to buy a Dremel to help with polishing my fingerprint jewellery. Most of the replies i got seemed to suggest I didnt need one and to use a Tumbler. I have got the tumbler back out of the cupboard again having not been happy with it when i've used it previously. I fired my pieces in the kiln yesterday and put them in the Tumbler last night for about 2 hours and I am still not happy with the finish on them. I have attached a photo so you can see what i mean. They are nice and shiny but a little mottled on the backs which i just cant live with. How do I get them smooth?
Did i not have them in the tumbler long enough or should i now be sanding them by hand or something? I thought the tumbler was supposed to do most of this for me?

Ideally, sand before firing, it's easier then and dust you catch can be re-hydrated for use. You can also sand before tumbling.

I don't do much of this, hopefully one of the mad-keen PMC people will give some perspective, but I just use 1200 emery paper.

You won't get a super mirror finish with tumbling, for that you'll need to use a polishing wheel of some flavour, but neither tumbling or polishing is appropriate for cleaning up the bumps, that's sanding or filing or perhaps working on a very smooth surface when the clay is wet.

Hi,

I don't work with PMC but I can tell you that using a tumbler will deburr rings and polish, it won't even out any bumps or deep scratches and the like. That kind of work needs to be done prior to polishing, any method of polishing. Agreed that you won't get a mirror finish with a tumber, you would need a polishing wheel, either the bench or pendant drill type, but it should be really shiny if you use stainless steel mixed shot and compound.

Frances

Yes we do sand and have a smooth finish before firing. And we are getting a shiny finsh when its come out of the tumbler, however there are more dimples in the piece after tumbling than before and its not the finsh we want to acchieve, therefore it looks like we will have to invest in a pendent drill or the like to get this finish before we wear out our fingers doing it manually.

Thanks for your comments.

It sounds to me like your shot is too large/heavy for the pieces you're tumbling. Metal clay is much softer than sterling, so can't take the big clunky shot. Try using a finer grade with some pins and it might just do the trick.

I have had the same problem, i put my pieces in that were sanded and smooth and they have come out with marks and dents in them. Where would i find a finer grade of shot?

My shot is quite fine. I bought mine from Hilton Brothers (?), also called Manchester Minerals. That was a few years ago now.

With fingerprints it's a little different as you can't leave them as long as you'd leave an ordinary
silver clay piece (or the shot will start flattening the print). I use it just to start the initial polish
(gets them to about the same as yours) then I use the pendant motor with the ruberflex burrs to do all the
rest (avoiding the print area).
That gets them to a suitable polish - I don't mirror finish prints as it makes it too visible when normal
wear and tear starts scratching the fine silver ;)
It gets them to about here.....
http://www.flickr.com/photos/muranosilver/4296595492/
Nic x
Nic x