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Product Query: Magnetic Tumblers


#1

I have, I’m putting together my wish list for the items I don’t have
yet for my studio (I finally got rental space – Yay!), and one of
them is a tumbler.

School == Rotary with mix steel shot media Recommendations ==
Vibratory with steel

Magnetic Tumblers are fairly new to those around here, once they have
something that works for them there is little desire to buy a new
tool that may equate to a toy for them.

Rarely have I tumbled, most of what I created in school had lots of
flat surfaces and the instructor wanted mirror finish, he was
addicted to it :slight_smile: Hence little opportunity to explore tumbling.

If I can get some advice from those with experience in these products
and maybe also as to when is best to tumble a piece and when is best
to use the polishing machine.

Kindest,
K. David Woolley
david.woolley@unb.ca


#2

Hello all at the Orchid festivities, miss you all!

Magnetic tumblers are one of the best friends any factory or
work-shop can have. Its an investment in time, cleaning and
production. No one should be without one. They are terribly
addictive, once you try it, and you’d swear where was I for the past
decades. What you’d be cleaning overnight and being away from the
rotary tumblers, will have a finishing in 30 minutes.

When I get an order for my silver casting for my classes, I ask my
caster to then tumble them, no extra charge, items are smooth, bright
finish and all so nice to view and easy to work on. Those ‘shots’ get
into everywhere and make the whole ring, or pendant shine as if with
a “pre-polishing” stage. No comparison to an un-tumbled and magnetic
cleaned!!!

After setting or manufacturing, the post polishing phase is easier to
finish. I used to work at a large factory last season, they had 4
large machines going ‘full tilt’, all day! Rotary tumblers are like a
"kids toy" as compared with the “real McCoy”, don’t hesitate or make
excuses in not buying one. They come in all sizes and prices,
suitable for all pocket books. These are really a fantastic
machine…“Maybe next year in Tuscon”…I will have lots to offer to
all…:>)

Gerry Lewy!


#3

David -

Your instructor did you a favor - he taught you what you need to do
to get a mirror finish. While he might have taught you how to use
tumblers, the technique you are trying to emulate with a machine
requires that you know what is happening in the finishing process
whether manual or automated.

Finishing involves smoothing and burnishing. The tumbler processes
you have seen are all burnishing - steel with rotary or vibratory
machines and the magnetic finishers all burnish. Then do not remove
metal, they hammer it in tiny bits.

The first part of finishing is to smooth the metal - you can do it
by hand with sandpaper or on the buff with Tripoli. You can also do a
very good job of smoothing with a tumbler - my favorite is a
vibratory flow thru with various grades of abrasive - depending on
what you started with. Cast work differs from fabricated, and silver
works differently from brass or gold or pmc.

After you have smoothed the work in your vibratory tumbler, you can
burnish it to bring up a reflective surface. The magnetic tumblers
work well on detail pieces - filigree, fine wire pieces such as ear
wires, and heads. They are pretty small and don’t accommodate large
pieces. My work horse is a rotary tumbler with stainless steel.

My solution to a perfect shiny finish, is this. After smoothing and
burnishing, the work is run in a dry media in a vibratory tumbler -
walnut shells or wood chips charged with simichrome or chrome oxide
or rouge. It runs for quite a while - 24 hours or more - and the
resulting finish is flawless.

I love my magnetic tumbler, but I don’t use it as much as the
vibratory or rotary. There is a bit more to this tumbling than which
one to buy.

There is a lot of on finishing on Orchid. There are also
reference books on the process. I’ve written a basic book on the
process - available from most of the major suppliers - Rio, Gesswein,
Otto Frei, Elaine Luther.

Judy Hoch


#4
Magnetic tumblers are one of the best friends any factory or
work-shop can have. Its an investment in time, cleaning and
production. No one should be without one. 

OK, you convinced me. I bought one. Now I have some questions.

Do the pins need any special care? Like, do I need to keep them
under solution like I do carbon steel shot?

The instructions say to store the bowl off the machine, but they
don’t say why. Anybody know why? Unless I have a reason I don’t
think I am going to remember.

If you are going to go for a complete tumbled finishing process,
where does the magnetic tumbler fall in the sequence of things. It
sure does not look like a final finish to me. It only takes a little
Zam to make it look done, but what if I want to do everything with
mass finishing? What first? What next?

I just bought the smallest Raytech machine, but if I like it I will
get a bigger one. Thanks in advance for all your fine advice.

Stephen Walker


#5

Hi Stephen,

At the Tucson show, Raytech was showing a couple of new bowls for
the magnetic tumblers. There wasn’t anyone around to talk to about
them when I was there so other than the description of the bowls my
comments may be incorrect.

The bowls I looked at were the same size (diameter) as the bowl for
the small magnetic tumbler used with stainless steel pins. The base
of them appeared to be about 1" (25 mm) thick. The bottom of the bowl
had a series of aprox 3/8" (10 mm) diameter holes (8 if I remember
right) about 3/4" (19 mm) from the outside of the barrel. The bottom
of the bowl was free to rotate within the bowl when the unit was
running.

The media being used in the demonstration model appeared to be some
sort of softer material (corn cobs ?) that was treated with a
polishing agent. They also had another unit the same size that had 4
plastic Christmas tree shaped units mounted in 4 of the holes,
dividing the bowel into quarters. The base of the ‘tree’ was about
1/4 the diameter of the bowl. the trees were free to rotate when the
unit was running. I was told by someone in a different booth that the
purpose of the trees was to keep rings placed on them separated so
they wouldn’t scratch each other.

I don’t know if the 4 Christmas trees are removable or if the unit
that had them was a special bowl. The media in both bowls rotated
when the units were on.

If I had to guess, I say the bottom of the bowl (the part with the
holes in it) was attached to a ferrous metal base that was caused to
turn by the magnets of the drive unit.

Guess we’ll have to wait to see the units listed in some of the tool
catalogs that provide a description & more info.

Dave


#6

I keep my bowl on my machine, I have for about 2 years with no
apparent problems. I keep the pins in the bowl. I occasionally wash
the pins and bowl with hot soapy water as it gets gunked up
[official term :)]. check the archives on magntic tumblers…someone
just posted recently with some good info.

Mary Frances Dunker


#7
The instructions say to store the bowl off the machine, but they
don't say why. Anybody know why? Unless I have a reason I don't
think I am going to remember. 

If you plan to leave your pins in the bowl, then indeed, do not
leave the plastic bowl on the machine or you will end up magnetizing
your pins. You’ll then have to demagnetize them or else they will
clump rather than move freely when you run your machine.

Donna Shimazu


#8
You'll then have to demagnetize them or else they will clump rather
than move freely when you run your machine 

Donna, how do you demagnetize the pins?

thank you


#9

On my unit I keep the bowl on the machine… and I always keep the
pins under the water… to keep them from rust…

Andy " The Tool Guy" Kroungold
Tool Sales / Technical
Stuller Inc
Phone 800-877-7777 ext. 94194
Fax 337-262-7791


#10

I as well love the magnetic tumblers. I only use pins in mind. I
start with 1/2 the amount of pins. Fill the bowl with water just
covering the pins and 2 teaspoons of burnish compound. Run a full
speed for 30 mins… if all is good they turn out to a prepolish
state. To clean the pins I run with the burnish compound only for 45
mins…

Andy “The Tool Guy” Kroungold
Tool Sales / Technical
Stuller Inc
Phone 800-877-7777 ext. 94194
Fax 337-262-7791


#11

One can buy demagnetgisers, and of course bulk audio tape and
videotape erasers are demagnetisers.

If you happen to know any home video enthusiasts, they might help by
using their machine. If pins or ball bearings clump together it is
because they are magnetised. As an example if you take a piece of
hardened steel and lay it on a bench in a North-South direction, and
give it a sharp bang, it will attract a compass needle, having become
magnetised in Earth’s field.

When I was heavily into manipulating sound tapes, I made a tape
eraser by taking an old TV transformer, removing the secondary coil,
and the primary produced a very powerful alternating magnetic field
(if the huge power demand didn’t blow a fuse or melt the primary
coil) and one simply lay the material; bearings, screwdrivers etc,
on a plastic tray in the field, and slowly moved the tray away from
the field, thus slowly weakening the field’s effect to zero.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#12

Most machine tool suppliers have flat 6" x 6" or larger
demagnetizers. Price ranges from about $60 on up. They are used to
demagnetize pliers, screwdrivers, cutting tools, and the like. They
work fine on shot placed in a plastic bowl on top of them. Shake it a
few times so that all of it gets exposed to the field.

Make sure you get the FLAT “surface” demagnetizer - not the "tunnel"
type where you pass the article through the hole in a coil.

Brian P. Marshall
Stockton Jewelry Arts School
Stockton, CA USA
209-477-0550
instructor@jewelryartschool.com