Was: How to use Tripoli compound?
Miachelle, I’m not sure the following answers your question
specifically about Tripoli but it might give you some useful overall
polishing hints. Hope it helps…this is a paper I prepared for my
students at the Boca Raton Museum Art School in SOFL.
Polishing Metals
Don Dietz, Aug 2007
Polishing is not as difficult to understand as many think. A few
simple rules help.
-
Never try to polish out scratches. If there is a scratch or
blemish you must first remove it first by filing if necessary
followed by successively finer sand paper…usually 300, 400 and/or
600 if the 400 is new and leaves a matt finish. The exception to
this is simple surface scratches with no depth. These can be polished
off. Remember, polishing is an abrasive process and as you polish,
you also remove metal. An experienced jeweler will plan ahead when
selecting stock to ensure the various clean up and polishing
processes don’t leave him/her with 26 gauge when 22 was intended. -
No matter what kind of polishing compound you use they all
basically can be referred to as ‘cuts’. First cut will be the most
coarse such as tripoli or bobbing compount, second cut will be
medium such as Fabulustor or ZAM but white diamond is considered by
many as second cut also, etc. Third cut will be the rouges such as
red rouge, gray rouge etc. -
Use the appropriate speed on your buffer lathe. Many people are
afraid of the machine and use only low speed…around 1700rpm. I
use 3450 almost exclusively unless doing some special job. -
Use the appropriate pressure on the wheel. Beginners tend to use
too little pressure and can’t understand why nothing is happening.
Use sufficient pressure to obtain a clear surface. If heavy black
areas appear (called “keep”) know that the polish is not doing its
job beneath that area. If keep should appear, just give a firm push
against the wheel in that area and it will dissappear. -
Do not overload your wheel with compound. Using two hands, press
the compound against the wheel only briefly to apply a light coat.
Reapply only when the wheel stops cutting. If you do overload the
wheel, you will need to ‘rake’ it off with a rake. The rake can be a
narrow board with nails in it that protude about 1/4 inch. This will
remove excess compound…it also reduces the size of the wheel! -
Protect yourself. Wear safety glasses, use a buffing board (a slip
of wood you can lay flat pieces on whilst you polish so the piece
won’t bend or get caught in the wheel. You can also use finger cotts
(leather pads with stretchy material that holds them on your
fingers). There are other items you can use on your fingers also.
DO NOT WEAR GLOVES! Gloves tend to get worn through and
tear…taking a finger with them. Keep all loose items away from the
wheel such as long hair, dangling jewelry (in fact, don’t wear
jewelry while polishing as it can be damaged). You can purchase
protective ‘finger cotts’ which are leather patches with elastic on
one side to hold them on your fingers. Use a wooden mandrel when
polishing the outside of rings so they won’t burn your fingers. In
our shop, we use polishing boards (3x6x1/4" pieces of plywood) to
polish flat pieces. Simply hold the piece on the board as you
polish…it supports the metal and allows additional pressure to be
used.
-
Never present a prong or protrudence against the rotation of the
wheel! The wheel will grap it, bend it, rip it off, or worse. Always
present the piece downward – in the direction of the wheel
rotation. -
Hold the piece firmly lest the wheel grap it from your hand and
fling it against the back wall of the lathe or out into the room
somewhere. -
Do not mix compounds on a wheel. Always mark your compounds or
place them in a unique bag, box or somewhere they won’t get mixed
up. Mark each wheel so you know what compound is on it. Because we
have a number of teachers using our studio, not all follow these
rules and we end up with various pieces of a compound but cannot
identify it (color is not always a sure thing). Keep it all separate
some how.
When it comes to what wheel to use, everyone seems to have their own
favorite. Generally, for first cut use a yellow (oiled) stitched
cotten muslin buff. For second cut, a white (unoiled) stitched buff.
For third cut, use a white unstitched buff. These latter tend to
come apart so they are usually held together with a leather, plastic
or even lead center. Felt can be used for ring shanks (inside and
out) but be careful doing large flat areas because they tend to leave
’chicken’ tracks due to uneven wear. Some people prefer wool, some
cotton, etc. Check it out.
Everyone has their own idea of which compound to use when. But if you
follow the above (substituting various compounds for each cut) you
will sort it out in time. One hint though, ZAM is wonderful for
polishing not only silver but also certain stones. Primarily the
carbonates/phosphates…malachite, rhodocrosite, turquoise, etc.,
and certain others: horn, black coral, plastic, acrylic etc. But ZAM
will not polish the silicates!
Sorry this is so long but its actually a synopsis of my buffing
lecture which takes about 30 to 45 minutes in class. A problem is
there are so many sanding, buffing, polishing etc materials out
there it takes years to learn what to do with what. If you follow the
above rules however, you should have a successful experience.