Tumbling - types of shot

[Victoria]

Hello
I've been using a tumbler with mixed steel shot but have found that it leaves pitted marks in the surface of the metal. While that can sometimes look quite attractive, I would like some shot that polishes the metal without marking it (especially for wide band rings, etc, where it really shows). What type of shot should I use (links to where I can buy would be *really* helpful) and should I use more/less shot?

Apologies if this has been discussed before, I see lots of threads about tumbling but can't find an answer to this specific question. If it has been discussed before would someone be kind enough to send me the thread link!

Many thanks
Victoria

[sonia]

Hi Victoria

I use a mixture of stainless steel shot - satellites, pins and balls and don't have a problem with pitted marks. The other advantage of stainless is that it doesn't rust. I leave mine ready to go in a bit of water and barrelling powder.

Hope this helps.

Sonia
x

[mizgeorge]

If you're using mixed shot, I suspect the problem will be your pins. Not all are equal by any means, and many mixes include pins with quite sharp edges. Try taking them out of the mix you use for pieces with larger flat surfaces and see if that makes a difference.

It is possible to smooth the pins by barrelling them separately with some grit, but it's a tiresome process, so you might just find it easier to keep different versions of your shot mix for different applications.

[Dennis]

It would be tedious to search for the original post, but my frustration was so great that way back I actually separated all the pins from my mixed stainless steel shot and tumbled them with seashore pebbles: no improvement.

I then ground the tips one by one, first with a silent stone and then with a rubber wheel: not much better.

I think you can only do as George suggests and keep some shot with no pins, so that you can use this for mainly flat areas. I have not tried it, but it might be possible to tumble with mixed shot for an hour or less to reach the recesses and then for a longer period with only balls and satellites. Dennis

[Victoria]

Thank you everyone! Picking out the pins from the shot should be fun :-)

Sonia - could you tell me what shot you have and where you got it from please? would be interested to see what yours is and why you don't have a problem with pitting. thanks!

V

[sonia]

Hi Victoria

I've just checked and my shot came from Suttons

suttons stainless needles 250g pe066
suttons stainless shot 2.5mm 500g pe063
suttons satellites 3x5mm s/steel 250g pe094

This is enough for two of my barrels - I have the double barrelling unit.

I've been tumbling today with no probs.

Sonia
x

[Victoria]

Thanks Sonia, that's really helpful!
V

[memattaylor]

Sorry to bump this thread but I have been having the same problem with my tumbling with mixed stainless, I havent tried taking the pins out as yet but my next batch of polishing is likely to be several pieces and I would like to minimise the chance of pitting before starting.

Just wondering if you resolved the problem Victoria and if so, how?

Thanks

[caroleallen]

I'm wondering whether you're expecting too much of your tumbler? A tumbler will never give a mirror finish and I only use mine for textured pieces.

[memattaylor]

That may be the case, the pitting was quite severe - I'll have to try again and post photos if it's not any better. The tumbler at 'school' has not had the same effect on the those pieces so is suspect the rods / pins may be stabbing my pieces into submission. Try, try and try again I guess.

Tumblers still aren't a replacement for good old elbow grease in all cases I guess.

[TeeDee]

Also had same problems with my first purchase of shot form UKGE due to excess of pins.
Bought some Cousins UK mix which is an improvement but not perfect for smooth finishes https://www.cousinsuk.com/catalog/consumables/barrelling-media/barrelling-media-shot-stainless-steel-popular-mix
If you don't fancy picking out the pins I guess the ultimate is to mix your own but it ain't cheap. Cousins/Suttons etc should all do different grades you can buy separately.

I still use my old pin rich mix for some textured surfaces such as reticulated or heavily frosted as it seems to work well for me
Tim

[memattaylor]

Thanks Tim and Carole, i think finding the right shot mix is key, advice much appreciated.

[Binraker]

I have had very mixed results with tumbling. I use the UKGS mixed shot too and have been contemplating how to get a better finish. Industrial tumbling and vibration polishing can give you and almost mirror finish and I have often wondered what mix of water/surfactants/media/abrasives they use since every shiny metal thing these days is polished in this way and you only have to look at things like Victorinox pen knives to see what can be achieved. I imagine there a different mixtures or different alloys, finishes and states. I would assume that the majority of the "high street" (H. Samuel to Argos) jewellery is finished like this.

Another thing that I have been wondering about is that the tumbling process also peens the surface making it hard again after annealing. So that's a bonus. Also if you anneal and pickle several times to bring the silver to the surface before tumbling that surface must be slightly porous and tumbling will randomly compressing this surface so will you get the best finish or more a "micro hammered" finish? It could well be something one doesn't need to worry about.

That said, I have usually found that any imperfections in the tumbled finish can be removed with a brass brush and/or a quick wipe with a cloth with some brasso (from an old can where most of the stuff has settled out)

[Patstone]

I have used my tumbler with mixed stainless steel shot and never had a pitting problem, I got mine from Manchester Minerals, all shapes including long bits.

[josef1]

not sure if this applies to tumblers but I guess it would,When I got new pins for my magnetic polisher the finish was almost frosted ,the longer I ran the pins the better the finish I got (up to a point I still need to be polish on the buffer) I think maybe the pins smooth themselves off with time and that would explain why schools are better as they have been used more only a theory though

[Didi]

I had horrible pitting the first time I used the mixed shot. Sat for an hour or so in the sun picking out the needles and haven't had a problem since. Nice to know you can buy the individual bits from suttons though. I'd say, pick out the needles, time consuming but worth it.
Didi

[memattaylor]

Thanks all, I guess the hour or so sorting should be classed as therapeutic and not a waste of time - especially if it works for me!

Thanks again.

Mat

[FloWolF]

I got my tumbler late last year having already read a lot of such tales, and sure enough I put a flat piece of sterling in for a test and it came out with trillions of tiny micro-scratches giving a slightly 'milky' finish - the pins have been cut from wire with standard pinch cut and each had 2 sharp corners and a razor edge each end.

I considered removing all the pins but felt daunted by the tedium of that, so figured I'd just save for some more of the other (round balls and planets) shot and keep 2 lots, but in the mean time I just set the tumbler running with just the shot, water and soap alone for about 12 hours total over 3 days and now it gives a vastly improved finish not too far off 'mirror'.



Shaun.

[memattaylor]

Thanks Shaun, another option which may be needed when I have thrown all the shot out of the window when trying to sort the pins out #-o

[mizgeorge]

Mat - you might want to try a magnet. The pins are usually attracted first and can be picked out quickly that way by hovering slightly above the mix.

[memattaylor]

Ah good point, is stainless steel magnetic? Is that a stupid question?

Something from an old physics lesson or suchlike is telling me that stainless isnt. Hmmmm, worth a try though thanks.

[mizgeorge]

Some is and some isn't! I use a very strong magnet, and it generally picks everything up - which makes sorting very much easier, especially for things like jump rings. The pins always jump up first - but my shot is perhaps different as it came from the US and the pins have lovely smooth ends.

It's much, much, much cheaper too...

http://www.riogrande.com/Product/Stainless-Steel-Shot-Mixed/339097?Pos=11

[FloWolF]

Some is and some isn't! I use a very strong magnet, and it generally picks everything up - which makes sorting very much easier, especially for things like jump rings. The pins always jump up first - but my shot is perhaps different as it came from the US and the pins have lovely smooth ends.

It's much, much, much cheaper too...

http://www.riogrande.com/Product/Stainless-Steel-Shot-Mixed/339097?Pos=11

Well that does look like a good deal - what was the cost like after shipping and customs duties?..


As for stainless/magnetism - 'austenitic' (austentite) stainless steels are non-magnetic, whereas martensitic (martensite), or stainless steels with high ferritic (ferrite) content are magnetic - basically it depends on the type of iron and iron compound crystal structures present, or so my imaginary lay-metallurgist informs me ',;~}~

Cheers!

Shaun.

[FloWolF]

Mat - you might want to try a magnet. The pins are usually attracted first and can be picked out quickly that way by hovering slightly above the mix.

Oooo, I like that idea... ',;~}~

Cheers!

Shaun.

[mizgeorge]

Well that does look like a good deal - what was the cost like after shipping and customs duties?..




On its own, it comes in under the £15 limit, so no VAT or anything else. I ask them to ship in a USPS flat rate mailer, which is less than $US20, so still cheaper than buying here. I've never found a mix here that comes even close to the same quality, especially for the pins.

[FloWolF]

On its own, it comes in under the £15 limit, so no VAT or anything else. I ask them to ship in a USPS flat rate mailer, which is less than $US20, so still cheaper than buying here. I've never found a mix here that comes even close to the same quality, especially for the pins.

Wonderful - thanks for that I'll more than likely get a second lot now ',;~}~

Shaun.

[TeeDee]

Some is and some isn't! I use a very strong magnet, and it generally picks everything up - which makes sorting very much easier, especially for things like jump rings. The pins always jump up first - but my shot is perhaps different as it came from the US and the pins have lovely smooth ends.

It's much, much, much cheaper too...

http://www.riogrande.com/Product/Stainless-Steel-Shot-Mixed/339097?Pos=11

Just looking at the close up photo it looks a far superior mix to both of mine. Can't believe the price including shipping is less than basic UK mixes. Wish I'd seen it before I bought the last lot!
Tim

[memattaylor]

It's certainly on my shopping list now, great tip thanks!