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Mass Finishing System


#1

Hi all! I am a student who would like to invest in a mass finishing
system. We have a tumbler at school (with stainless steel shots)
which i really like, but i’ve also heard from other students that
they prefer the vibrating finishers. I am currently producing mostly
mixed metal brooches and some boxes, eventually, i would like to
produce cups and tumblers. Can someone tell me the advantages and
disadvantage of both machines? As well as the differences of the wet
media vs. the dry media? One more thing, if the finishing systems
are not suitable for cups and tumblers, how would one go about giving
them that nice high polish?

Thanks a bunch in advance, Kai-Ti.


#2

Hey, the tumbler is primitive compared to the vibrator, there is no
comparison, as I have done both. Also we thought that the black
plastic could not take the shot restorer, but what I found is once
you get a layer off it, then it will quit coming off and restorer can
be used. I would not go back to a tumbler if offered it and all
supplies free…I use one of the smaller versions, not the flying
saucer looking ones…real pro description. Jay


#3

Hi Kai-Ti, A vibratory tumbler is generally more versatile than a
rotary tumbler, in that the vibratory can run a variety of different
medias for both cutting and polishing (such as ceramic and plastic
abrasives, walnut shells for polishing, steel shot, etc.). It can
run all these medias effectively and in a reasonable time frame.
This is because the entire tub of media tumbles (or vibrates) so
that all the media is acting on all the parts all the time.

On the other hand rotary (or barrel) tumblers work by turning a mass
of media and parts around and around in a barrel. Basically, the
action occurs only in the top layer of media as it slides down with
each turn of the barrel. Still, in my opinion, a rotary is the best
tumbler for running steel shot. The weight of the shot combined
with the rotary motion makes for great burnishing especially of
silver (and it also work hardens the surface of the jewelry).

Rotary tumbling is not as effective for lightweight medias such as
walnut shells. Walnut shells might take 16-24 hours (overnight) to
achieve a high polish in a vibratory tumbler, but more than twice
that long in a rotary tumbler to get the same finish.

(Disc finishers, by the way, offer the same versatility in terms of
media types as the vibratory tumbler but disc finishers have MUCH
faster processing times. They’re great for production and when time
is a factor in your finishing. Magnetic tumblers are also fast but
they are specifically designed to run one type of media (tiny steel
shot pins) for getting into highly detailed areas or undercuts or
into settings. In fact, all the areas that are difficult to polish
by hand, magnetic tumblers can polish to a high shine and very
quickly too.)

So if you looking to do some cut-down steps as well as polish, you
probably want to look at Vibratory Tumblers (or Disc Finishers). If
you’re looking only to polish, then a Rotary Tumbler is a good
option too.

The size of your parts (and the number you want to run at one time)
determine the size of the tumbler you choose. The tumbler bowl or
barrel has to be big enough to let the part tumble around freely in
it – so, for a cup, you’d need a pretty large tumbler! A rotary
tumbler might be the best bet for something this large since a
relatively small unit could accommodate one cup. However if you want
to tumble several cups at once, you’ll need a very large barrel.
The idea is you don’t want to have too many parts in the tumbler or
they will bump into and scratch each other defeating the purpose of
the system.

Generally speaking about a 10 to 1 ratio of media to parts by volume
is desirable. However that ratio will vary somewhat depending on the
media you use.

Steel shot is a great media for burnishing sterling and silver but
many many people like it for gold and other yellow metals.
Personally I prefer walnut shells (treated with red rouge) for
polishing gold and yellow metals. I think it gives a warmer finish
– but that’s just my personal opinion.

Many suppliers will run samples for you at no charge. You might
want to check that out prior to purchasing a tumbler – it can save
you a lot of time and experimentation as well as money.

I hope this has been of help.

Best Regards,
Elaine Corwin
www.gesswein.com
Gesswein Co. Inc. USA
Bridgeport CT 06605
Tel: 1-800-544-2043 x287


#4
      Hi all!  I am a student who would like to invest in a mass
finishing system. We have a tumbler at school (with stainless steel
shots) which i  really like, but i've also heard from other
students that they prefer the vibrating finishers.  I am currently
producing mostly mixed metal brooches and some boxes, eventually, i
would like to produce cups and tumblers.  Can someone tell me the
advantages and disadvantage of both machines?  As well as the
differences of the wet media vs. the dry media?  One more thing, if
the finishing systems are not suitable for cups and tumblers, how
would one go about giving them that nice high polish? 

Kai-Ti - Lets do the basics first. There are three processes or
steps in mass finishing. First you need the abrasive or grinding
step to smooth the surface. This is usually accomplished with a
vibratory tumbler and abrasive media. Then you can do burnishing
with steel shot, usually in a rotary tumbler. The third step is a
refinement of the second one, and is a buffing process, usually done
in a dry vibratory tumbler with wood chips or walnut shells charged
with some sort of polishing compound. You don’t always use all
three processes or even use them in this order.

The vibratory tumbler is effective for moving the lighter (than
steel) media against the work pieces. When grinding, the process
should be wet, with the best results with the liquid flowing thru
the media. Most shops use a rotary tumbler for steel because the
cost of a vibratory tumbler that would move shot is many times the
cost of the vibratory - and further there is no time advantage to a
vibratory tumbler for steel.

The problem that you pose with larger pieces such as cups, is that
the work pieces need to move freely inside the tumbler, thus
requiring a much bigger machine which gets expensive. You also have
to buy lots more abrasive media to fill it up. And the abrasive
media gets used up in the process.

Unless you are rich, you are left with hand finishing large pieces,
or devising a finish that doesn’t have to be polished - peened,
oxidized, brass brushed, pumice rubbed, scotch brite are some
suggestions that come to mind.

For more Rio Grande or Frei and Borel sell a small book
that I wrote on the subject. It details the likely costs, and lots
more detail on the process than most Orchid folks would like to wade
through. Book is “Mass Finishing for Handmade Jewelry”

Judy Hoch, G.G.
@Judy_Hoch
www.marstal.com


#5

Good info Elaine. one quick note about mag. pin finishers -steel
pins runnimg at a speed greater than half of maximum will create an
unwanted impingement on jewelry. the solution I found is 1.2 mm steel
balls which erase the effect of the pins. available (to my knowlege)
only from Romanoff ph. 1-800-221-7448 christine Talrico x128