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Tumble finishing castings


#1

Hi All Orchid Friends,

Does anyone know if I can tumble finish sterling castings in a common
Lortone tumbler? The one I have is a 4lb. unit. I would like to
polish several pieces at once. What kind of polishing material do I
need. Will this work?

Thanks for all of your input.
Sharon Bloom


#2

Sharon, Rio Grande has a section in there Tools and Equipment catlog
page 272 that gives you info on tumbling. I now have a vibrator
tumbler, but used a Lortone for years.

Good Luck, Silverbear


#3
Does anyone know if I can tumble finish sterling castings in a
common Lortone tumbler?  

Sure you can! I do it all the time. Just clean them up and toss them
into the tumbler with enough steel shot and a small quantity of
burnishing compound and let it run until you are satisfied with the
finish. Dee


#4

Sharon, I use plastic media in a vibratory tumbler to prefinish and
find that it does well with smaller pieces, but with larger sterling
castings, particularly medallions they tend to wear off at the edges
faster than they clean in the middle. The the word is to check
frequently and don’t go off for the weekend leaving the tumbler running! Geo.


#5

Hello Sharon, Yes you can tumble silver findings in a regular tumbler.
I use mixed stainless steel shot (you can use regular steel) that can
be purchased at any jewelers supply. This is made up of rod, pin, and
sort of disk shapes. I add about an ounce of regular wisk to the mix.
Use hot tap water (this stops the tumbler from springing open).
Tumble for a few hours. Before you tumble remove all investment and
pickle the castings. This cuts down the tumble time. Good luck. Steve
Ramsdell


#6

I have a lortone tumbler (rubber barrel) and use stainless steel shot
(mixed sizes and shapes - available from Rio Grande and IJS, among
others) with just enough water to cover the pieces I am tumbling and
the shot and a tablespoon of the liquid Rio Grande has for tumbling.
Although I had an instructor who used plain diswashing liquid soap and
it turned out fine! I would advise stainless steel shot over just
steel shot- too easy to rust the latter and the former just needs to
be rinsed between uses with clean water and dried (I use a dish
towel). Good luck.

Shael
dakotahdog@msn.com


#7
   Does anyone know if I can tumble finish sterling castings in a
common Lortone tumbler?  The one I have is a 4lb. unit.  I would
like to polish several pieces at once.  What kind of polishing
material do I need. 

Hi, I polish all my silver pieces in a small Lortone tumbler. I got
stainless steel shot from Rio Grande, and some of their Super
Burnishing soap. I have not tried it on any castings but if what you
want is a good polish-and-work-hardening job it works great.
(Stainless steel is good as you don’t have to worry about the shot
rusting between uses.)

I think some people use things like walnut shell, and plastic bits,
too. Be interesting to see what other answers you get!

Cheers!
Margaret


#8

Sharon - yes you can tumble finish sterling castings, even in a small
rotary tumbler. However - first you need to clean them up - that is
clip the sprues, file and sand. Remove flash. Then you run 2 or 3
sessions of 3 to 5 hours each in a cut down media, first one should
be quite aggressive (for castings). This media can be brown plastic
pyramids (Gesswein) or Pink Clean Cut (Rio Grande Albuquerque).
Rinse your workpieces well. Follow with a less aggresive media, such
as green plastic pyramids, or aqua Clean Cut. I’d run the second
media twice, rinsing between sessions. Then you need a burnishing
step - in a rotary tumbler such as you have, this needs to be steel.
Run for two to three hours. Use an appropriate deburring liquid with
the cutdown stages, and a burnishing liquid with the steel. These
special liquids have cleaning agents, surfacants, and special
chemicals to retard oxidation, as well as lubricate the movement of
the media.

Good luck. Judy Hoch


#9

hello to all,

Another addition to this tumbling with regular soap.If you get tomuch
foam,just add some alcohol to the solution and that will take care
about overproduction of foam.For what it’s worth it.

Regards Pedro
Palonso@t-online.de


#10

Here I am again, with my burnt stones…I am the one the had the fire
New Years Eve… in my shop and all my foil back stones were burnt…
My husband has pryed open the drawer compartments to try to salvage
some and their is alot that I can re-use. I am tired of cleaning and
buffing them on a rag. Can I use my tumbler for this without the foil
coming off the back… Any sugestions… also, I am very interested in
the sterling compounds for polishing silver… Will this work for my
estate pins, that always need cleaned up… Also if you don’t mind. I
always have Gold filled, plated, pot metal, brass, copper… because I
am self taught, I am always learning… I would love to use the tumbler
instead of my big buffing wheel and my drummel… thank-you… Donna


#11

The discussion about tumble-polishing castings has reminded me of a
question I’ve been wanting to air for a while.

We use stainless steel shot for tumbling our silver castings.
Funnily enough, despite the same process being used all the time, the
end results are inconsistent. Sometimes the finish is excellent,
other times the same designs can come out with many tiny dents.

Everything throughout the tumbling process is weighed and measured
every time. (We use 150ml C6 Dreher liquid.) Every tumble is exactly
the same. So why the different results??? There must be some
variable we haven’t thought of - but what is it? Any suggestions
gratefully received.

Could the following piece of info be a clue, or is it a separate
problem?

The stainless steel shot sometimes turns black and smells ‘rusty’. (I
thought it was called stainless because it didn’t rust!) It will be
fine for weeks and then suddenly go black, for no apparent reason.
Can anyone suggest why this might happen, and how to deal with the
black and smelly shot? At the moment we wash the stuff and put it
back in and that usually fixes it.

After having read Orchid for a couple of months, this is my first
posting. Looking forward to hearing from all you people who always
seem to have good ideas about everything jewellery-related!

Cheers,

Duncan McLean


#12

It will turn black if you leave investment on the castings. Just
clean under cold water and tumble in pure soap powder the type you
wash wool jumpers in. Phil


#13

You probably polished your silver at least to a certain extent with
Tripoli before you tumbled it, right? I’ve found that, at least in my
case, the black color is due to the Tripoli lodged in the little nooks
and crannies that didn’t get washed off thoroughly.

Cheers,
Margaret


#14

Duncan: Any steel can rust because it contains iron and rust is a form
of iron oxide. Stainless doesn’t rust as easily as other types of
steel because it has a high chrome content. You stated that after
you clean the shot it seems to work ok. This may be a clue. The
missing variable may be in your shot cleaning procedure.

Tim


#15

For the problem of dirty steel, stinky steel etc. ; there are two
easy fixes: 1. every time you empty the tumbler, rinse the shot
thoroughly in running water. ; If you have black marks on your rubber
gloves from the shot, add a big squirt of Dawn or some detergent and
hot water and slosh the stuff for a bit. ; Then rinse and the steel
will be squeeky clean. Add a stale can of Coke to the shot, and let
it run an hour. ; Rinse well. ; Also results in clean stuff; This
works because of the high acidity of the coke I do question the small
amount of burnishing solution you are using. ; What size tumbler are
you using? ; The shot should be covered by 1/2" or so in burnishing
solution. ; Also how clean are your work pieces before you start? ;
Some times pins in the steel make pock marks. ; Take out the pins
unless you have very detailed work pieces. Judy Hoch
judy@marstal.com


#16

Hi Tim, What’s you recommendation for cleaning shot? I just cleaned a
bunch of sprues in my Ultra 10 Thumlers Tumbler. Turned out I was
also cleaning a piece of mystery metal, probably iron. My shot now
looks shot! And, yall, I need a little more help with the shaker:
It makes such a terrible racked that I expect my neighbors to complain.
Where should I look for the


#17

The best way to clean stainless shot that has been contaminated by
iron (rust) is to have in passivated. Your dentist may be able to
have it done for you. Tim


#18

I think I was about to say, “where should I begin to look for the
source?” Meaning how can I figure out what’s making my shaker so
noisey so that I can fix it.

I love my little laptop, but the thumb bar is just under the space
bar. If I’m not careful I send ‘half messages’ far and wide, and
this was the case here.

Always grateful for your help,
Joyce


#19

Chris and Barbara- We use a magnetic tumbler in our shop and are very
pleased with it, but we do not try to go straight from the tumbler to
the showroom. It is very efficient at polishing the insides and deep
carved areas of castings that are difficult to polish by hand. It
will save you labor if used for this purpose. Think of it more like
stripping the castings, only you don’t pour a bunch of cyanide down
the drain when you’re done. It is also very handy as a polishing step
after you have soldered heads onto a mounting. It will polish in
between, underneath, and all around, and even those hard to get to
prongs on a six prong tiffany head. But you will still need at least
a firm rouge polish before you can put it on display. My experience
has been that file marks will not be polished out, neither will
scratches or nicks, no matter how long you tumble. We generally just
throw all our freshly cast pieces into the tumbler for half an hour
or so. Once your expectations for the results are in touch with
reality, you will probably find many uses for your tumbler.
Experiment! Try it at different stages of production and find out
what suits your needs. It can be a great labor saver.
Marggi


#20

At I.J.S., we tumble-finish our castings in big Gyroc vibratory
tumblers.

Stage 1 is plastic, that is abrasive-impregnated.
Stage 2 is a ceramic media.

Media used for your purposes will vary, just start rough and go to
smooth.
Dan