I have taken an introductory metalsmithing class, and though I
learned a lot, I wasn’t taught the underlying principles which guide
which tool and/or method to use in a given situation. One such
question is when to use a Flexshaft vs filing and sanding to bring
the piece to the step before polishing with compounds such as Rouge
or Tripoli. We made a constructed ring and after filing sanded the
flat sides with paper but used the shaft with sandpaper for the
inside and the edges. Why not do the whole job with the flexshaft?
How does one determine this choice? I’m more than happy to experiment
on my own, but if anyone know of a good book, article etc., or is
generous enough to give some input, I would be grateful.
One important thing about using the flex shaft is knowing what spots
on a certain piece of jewelry will best be done without leaving worn
spots that will be not only seen but, very difficult to remove.
Always keep the hand piece moving one small delay and depending on
the abrasive wheel or brush will leave unwanted flaws on the surface
or take off detail that you worked so hard to impart on the piece. I
often use sand paper glued to popsicle sticks of different grits to
finish small areas before polishing. Anyway, here’s a great book to
give you more then you’ll need to get the most out of
your machine. { The Flexible Shaft Machine } By Harold O’Connor It
was published by Dunconor Books, P.O. Box106, Crestone, Colorado
81131
One such question is when to use a Flexshaft vs filing and sanding
to bring the piece to the step before polishing with compounds such
as Rouge or Tripoli.
In my practice I use flexshaft only when there is no other options.
Flexshaft is the worst tool to use for sanding, but there are
situations when alternatives are too cumbersome and too time
consuming. I do not know if you were taught how to make emery buffs
for hand sanding. This is one of those skills that do not look or
sound very exiting, but absolutely indispensable for quality work.
Mary, unless the area is very small I don’t use my flexshaft to
sand. I use my flexshaft on the insides of rings and between bezels
where I can’t use any other tool. My rule of thumb is to use the
largest file, emery stick or drum sander width on the piece that I
can use. Much of my work is characterized by large open areas of high
polished metal and the smaller sanding/filing methods tend to leave
grooves which become visible when the final high polish is done.
Please feel free to ask questions off post,
Sam Patania, Tucson
there are many answers to your question. Imnho, on a flat surface
like the flat side of a ring; use a flat file thats as large as
possible, then a flat emery stick, then a flat lap and then a very
light buff. For an outer curve like the back of a ring shank; use a
flat file workingwith a rolling motion, then a flat emery stick, then
a coarse buff followed by cleaning and then a light buff. For a
curved surface like the inside of a ring,; use a half- round file
and then an emery drum, then a coarse inside ring stick on the
polishing machine followed by cleaning and then a fine rouge inside
ring stick. There are many other shapes that need different tools,
but this might help you start.
Using a sanding mandrel on a flexishaft for the inside of a ring is
something that we do, although you could sand by hand, however the
inside of a ring is rarely seen once worn.
Using a flexishaft on the outside of a ring, say a half round
wedder, you might find you end up with flat sections, or worse the
bit runs away and leaves a very deep scratch in the surface of your
work.
At the end of the day, whatever you choose to work with is your
choice.
Use the technique or tool that’s most appropriate for the task and
your skill/comfort with it.
I see a number of people like to hand sand from really coarse to
exceptionally fine. Personally I can’t see inducing extra-coarse cuts
into your work, only to spend a lot of time removing them. Why not
start with something that’s just enough to do what you need done? It
really depends on what tooling has been done prior to finishing. A
disadvantage is that sandpaper can imbed grit into the metal. You’ll
wind up with what looks like a knot that leaves polishing streaks
around it and the more you polish the worse it gets. Little comets
that multiply as you change polishing direction trying to be rid of
them. If you have to sandpaper its better to not reverse direction
while the pressure is on. Go off the end of the paper or lift the
work at the end of a pass or go in circles.
A good 2 speed bench buffer can take the pain out of polishing. In
most cases #220 finish can be smoothed away on the buffer, (except
for platinum). To sand up to 1600 and over doesn’t gain anything
imho.
It could be that some schools teach hand sanding for practical to
them reasons, cost and safety maybe. This is mostly not the way of
industry though. In industrial applications one needs to get a good
finish quickly and cheaply. I can see some eyes rolling already.
Suffice to say that commercial outfits do what they do for good
reasons. When you’re comfy with machines and such maybe you should
try some of those techniques.
For prepolishing and final finish generally use the largest tool
suitable. This is why one would not finish a large bracelet, for
example, solely with a flexshaft. Small wheels leave a repetitious
pattern, where the wheel marks overlap, vaguely as a harlequin
pattern. For broad smooth areas a wider, larger diameter wheel (pick
your wheel speed carefully) can often finish in a single pass, no
overlapping needed. Keeping the work oscillating sideways in relation
to the wheel will help avoid those long curvey streaks that happen if
you feed the work into the wheel.
You can do an awful lot with a flexshaft. Don’t dismiss it but don’t
overburden it. Subject unto itself.
Using a sanding barrel on the outside of a ring something I learned
by doing a lot of clean ups of casting.
Using a sanding barrel on the inside suites this type of sanding
since your using a round sanding object to sand a concave surface. It
doesn’ t matter what pressure you use.
Sanding the outside is a different thing. You need to use a very
light pressure and it will take you longer.
You also have to change directions that your sanding. Plus your
following the contour.
Finishing the ring with a sanding stick will produce the best
results.Getting the desired result is just a matter of practice.
Jim
Jim Zimmerman
Alpine Custom Jewellers & Repair
Thanks all for your input. From what I’m gleaning there is much less
control with the flexshaft than with using one’s own hands (and
sandpaper) to finish a piece. It definitely makes sense to me to use
the largest sanding tool for a given area to reduce possible uneven
surfaces and/or scratches. Leonid, can you explain more about “how to
make emery buffs for hand sanding?” Are you referring to using a
paint stick and wrapping it with sandpaper with progressively finer
grits? Also, does anyone use burs to texture their work? I’ll
definitely check out the book you mentioned Mark, thanks.
Weather I use the flexshaft or sand paper depends on the piece. Wide
flat areas show blimishes and defects more, therefore sanding with
various grits then polish for the final step seems to work well. Even
the most experianced jeweler can have problems controling the
flexshaft.
Are you referring to using a paint stick and wrapping it with
sandpaper with progressively finer grits?
Here is how I was taught to do it:
There are 2 must have shapes - triangular and round. Success with
hands buffs depends on how well they made.
To make round one - take round stick (1/4 inch for goldsmith work )
and wrap emery paper around it. It is unlikely that just by wrapping
a proper tension will be achieved. So after wrapping, place buff on
flat surface and with another flat piece of wood repeatedly perform
forward strokes by placing flat piece on top of the buff and applying
forward pressure. Pressure applied only in forward direction. After a
hundred strokes or so, the paper tightens around the wooden core and
forms useful and long lasting buff. Ends are secured with binding
wire or tape or whatever.
Triangular is made differently. If triangular core is not available
a round one can be used. Align edge of core with edge of emery sheet.
Take something pointed, but not very sharp, (I use old bur ground to
a point and held in pin vice) and score paper on the inside using
edge as guide. Scoring should be light. Intend is to enable paper to
fold creating sharp corner, not to cut it off. Fold along scored
line. This will bring another edge in contact with paper and the
process is repeated. Continue until complete sheet is wrapped abound
the core.
Round core used the same way, except that first few folds are done
using ruler, and after that folding continues using previous layers
as a core. Practice requires to achieve tight, well formed buff.
Paint sticks can be used to create flat buffs. Also, simply using
folded emery paper in hand is a great way to sand. Hardness of such
buff is controlled by how many layers of paper one uses.
Advantage of multi-layer buffs is that when one layer is worn out,
it simply peeled off exposing new layer, so a buff can last quite a
while, even in a busy shop.
Modern Variation:
For polishing papers like 4/0 the above does not work very well, so
I make single layer buffs using aluminum core. Aluminum flats are
expensive but sometimes it is necessary to have fine grit buff.
Take adhesive on both sides tape, for installing carpets. Peel off
paper on one side, attach it to aluminum core, trim off with scalpel,
peel of second side and attach it to emery paper. Technique can be
used on convex or concave profiles creating almost limitless
variations.
I am newbie and taking classes from a art college, learn lots of
stuff, I do use the wrapped sandpaper with paint stick and use burs
to texture some of my designs. I also find when finish and there are
still some scratches on my piece, but learn few tips from here to
improve my surface, thanks for all those tips from everyone.
Flex Shafts are great, but your hands are your best tools. But, and
here is the but, certain actions in fabricating jewelry are really
fast with a flex shaft if you know what you are doing.
In fabricating, the questions are, “what am I making, and what do I
want to achieve?”
If you need to clean up some scratches around a soldered bale, and
you have 25 of them on your bench, a stack of 3M radial bristle disks
are a beautiful thing.
If you are working on one half round ring and getting it ready to
polish, then using a split mandrel with different grits of sandpaper
is very time efficient and easy.
For your hands, using a sanding stick is a great hand tool and I
like them a lot. Wrap them around dowels, half round file, flat paint
stick or just use them with your hand. Use Wet/Dry to make a good
slurry of grit and keeping the dust down.
In order to use a flex shaft effectively, your hands need to know
what to do first. A flex shaft is a great tool, but it is a tool for
your hand. Your experienced hands will guide you to a range of tools
to help you work more efficiently.
This is where practice, practice, practice comes in. In dentistry
when the High speed drill was first introduced (350K RPM) there were
many dentists Who were against the use of the high speed because
control was hard and it Could be dangerous. By practicing and
respecting the tool and speed it was Adopted by ALL.
My wife taught me the advantage of hand filing and sanding when
dealing with Flat surfaces. For everything else I like power.
Trying to get a smooth even polished surface is but one extreme end
of texturing.
Ball burrs, hart burrs, heatless wheels, the nasty large ones for
grinding inside of shanks are a few which come to mind quickly. Lots
of possibilities. Play with anything you can find, you will find some
nice textures.
One thing I like to tell my students is that if you want a flat
surface, use a flat tool ( files, sanding sticks) to create it. If you
are working on curved surfaces, use a curved tool, like Mizzy wheels
and rubber wheels. Very tough to make something flat with a flex
shaft.
A neat trick is to use a diamond bur held up to rotating white rubber
wheel to shape it to the form you are trying to create in the metal.
As an example, on a half-round ring band, you can shape a rubber
wheel to the exact profile of the band, and run the newly shaped
rubber wheel around the band’s exterior to give it a perfect contour.
Years ago, I bought several different shapes of wood - round dowel
of various thicknesses, half round, quarter round, flats, and make up
a whole bunch of sanding sticks - 360 - 800 grit, a few 1200 grit.
Some of them have two grades of sandpaper, one at each end - say 400
& 600.
I cut the sandpaper to fit the length, tape one side to the wood and
lightly score at each corner as I wrap. I use masking tape to bind
the ends, and as the paper wears, it’s easy to remove the worn part
and reveal a fresh surface. I know some people use a flat headed
stationery pin, but I prefer masking tape - it doesn’t scratch, and
I use it to mark the grit number in texta at each end. The whole lot
live in a 1 litre yoghurt jar on my bench.
I’m sure Leonid or someone else will give better directions for
making sanding sticks - my two bob’s worth is just that lots of
different shapes have proven useful to me.
Of course I use my flex shaft for some jobs, like inside a ring, but
the sanding sticks get a good work out every time!
it is so true.