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Ring polishing - mirror finish


#1

Hello all you experts out there !!!

I recently started making titanium rings on my lathe and am enjoying
both the creative and technical aspects of the work (as well as the
social connections that come with selling jewelry!). Okay, so here’s
the reason for my post - I have not been able to achieve the
mirror-like finish I am looking for. I’ve been using a bench
grinder, an old buffing wheel (part of the problem!?) and red
polishing compound, but it’s just not doing the trick.

Since titanium is a relatively hard metal, I am guessing that the
polishing needs to be a multi-step process: 1st step - use courser
wheel and polishingcompound to smooth out the rough spots. 2nd step

  • use medium course wheeland compound. 3rd/4th steps - use finer and
    finest wheels and compounds. Does that sound about right?

My bench grinders have a 1/2" straight shaft and turn at about
3,500rpm.

Can anyone recommend which buffing wheels and polishing compounds to
use (for titanium) for steps 1-4?

And what about for polishing the inside of the ring? I have seen
tapered shaft attachments for bench grinders with course to find
properties. Which would you recommend?

With much appreciation and thanks!

Sean Ward
Sacramento, CA


#2

Hi Sean,

Now you dont say what grade of titanium your using. Thats the 1st
thing we should to know.

Ive tried the V6A4 alloy but find that the commercially pure is by
far the best to use for jewellery making. So finishing? what you use
as buffing wheels depends on the turned form of the ring. if its
curved both in and out in section then most normal jewwellery wheels
will do, however, if the final turned form is with flats and sharp
edges then to a void wearing these away in the finishing process you
have to use hard felt wheels as the supporting medium for the
compound. stitched cotton is a good wheel to start with.

Next 3500 rpm is fine up to 3in in dia, but on a 6in wheel, you need
1500 rpm. Then a parallel shaft is not easy to use as your changing
wheels every 5 mins. you will need an adapter that has the same
internal dia as the motor shaft and there locked together with small
allen screws that do not protrude above the adapter.

Next you need a 3M compressed scotchbrite wheel thats part no 18762
DB/wl EXL. 6in by 1 in with a 1in parallel internal bore. youll need
to press in a tapered hole insert to use on the tapered adapter.

This has a grit size 9sfn. Regret 3M dont say what the actual grit
size is, tho mine here is 1000 mesh. Thats The only grit that
actually cuts titanium.

It could be silicon carbide, if not then its ali oxide. the former
is better. Titanium is a funny stuff to finish, as you have found
out. Next I use a white silica compound called Highfin, you need to
find an equivalent.

Next rouge is not needed at all. a green chrome oxide will finish
your rings best.

Thats the outside, Next the inside. Use a tapered soft pine broom
handle 12in long from the 6in mark taper it down to 1/2 in.

Put compound on the wood and get the wheel to spin the ring on the
wood. use a different piece of wood for each compound.

If you can make an adapter to hold the ring in your 3 jaw chuck then
a likewise tapered piece of wood with wet and dry glued to it will
help finish the inside before polishing. When youve got that far get
back here and update us how you find polishing titaniun, its not
easy.

Ted
In UK,.


#3

Does anyone else out there have any recommendations for which
polishing compounds you find work best on titanium? My suppliers are
recommending that I start with bobbing compound, then go to white
diamond pre-buff, then finish with white rouge.

What about the buffing wheels? The suppliers recommend that I start
with a yellow treated buff, then a Muslim buff, then a flannel buff.

It seems the reps from the big suppliers are often reading a script,
so I would really like to hear from all of you jewelry makers out
there who have polishing down to a science.

Ted, thanks again for your tips. I look forward to your comments


#4

Hi Ted,

Thank you for taking the time and sharing your knowledge.

I am currently using the aircraft grade titanium, 6AI/4V. Why do you
preferthe commercial grade? Does it machine better or finish better
or both? The primary styles are variations of a “pipe cut”, so flat
on top with small radius on the corners.

I ordered a couple of the 3M Scotch-Brite wheels, same spec that you
recommended. What is the sequence exactly? Do you start with a
Scotch-Brite wheelwith the white polishing compound, then go to a
Scotch-Brite wheel with thegreen compound, then go to a cotton
flannel buffing wheel? Which compoundor compounds do you use with
the flannel wheel?

Thanks again!
Sean


#5

Commercially pure is the softest titanium you can get. As I cold
forge the sheet into articles like bowls and dishes. its the best. I
make rings from the same grade from wire The joint is fused then
finished so you dont see it.

Next, the polishing sequence I use is as follows.

  1. deburr edges with a linisher belt.

  2. scotchbrite wheel all over to smooth all forging marks

  3. hard stitched cotton or woven sisal with the highfin

4.finish with either a felt wheel or cotton wheel to get the mirror
finish.

You will have to experiment with the above to suit your
requirements.

I need the mirror finish for the next process thats kiln firing for
colour.

Thats where the comm pure is also the best.

Ted


#6

Sssh! This is a secret…

Providing you have uncontaminated mops you can polish titanium in
exactly the same way that you’d polish silver or gold. with tripoli
and rouge.


#7

Who makes the best buffs and polishing compounds, or are they all
about the same? Rio Grande vs Gesswein, etc. ? Which brands work
best. Rio or Luxior TP-400 from Japan? Do you use something to clean
the buff periodically?


#8
Providing you have uncontaminated mops you can polish titanium in
exactly the same way that you'd polish silver or gold. with
tripoli and rouge. 

What diameter and rpm for the buffs do you recommend?


#9

I got into this when my wife lost her platinum and diamond wedding
ring set (she found them 18 months later). I’m a machinist and
decided to make her a replacement set out of titanium (before she
found them). Then some friends saw them and asked if they could
order one, then I started selling them at art and craft shows, and
now I’m starting a small business and building a website. Until now
I’ve made them with satin finish only. Now I’m expanding theline,
offering several finishes and have struggled with the mirror finish.
I’m using an 8" cotton buff at 3500rpm with red rouge and I can’t
get past an orange peel finish. I figured I would try 4" and 6"
buffs with several different polishing compounds and see which
worked best. If you experienced jewelers out there would be willing
to share the exact size, speed, type and brand of buffs and polishes
that work best for you, it would be greatly appreciated. I will let
you know how it goes.


#10

I just started making jewelry/rings. Titanium is the only material
I’ve worked with so far.


#11

Hi Sean,

Ive just read your post, how you got into this, and see that your
still struggling with your polishing.

Now your lucky, like I am, your from an engineering background and
your problems will need to be solved with an engineering solution,
not like so many poor souls who struggle with the simplest of
engineering problems here trying to make the simplest of ideas.

So your going to have to approach this problem of yours like an
engineer. Id suggest you find somewhere near you that uses titanium
in its varius alloys, which you have one of, and get some
commercially pure sheet. Say some 4 by 2in by 1/16th in thick and run
some controlled trials with your scotchbrite wheels running at
various speeds. You really need to move away from using your bench
parell shaft bench grinder at 3350 rpm. Build yourself using say a
1hp 1440 rpm motor, to which you have fitted a a 3 step pulley. then
have a seperate shaft driven from this pulley, an A section belt to
another 3 step pulley with 2 plummer blocks supporting it with taper
ends to take the wheels. You know from your machinest work that you
need the right tool for the job, otherwise its an all day exercise to
get where you want.! Now you go on and mention orange peel effect.
This is caused by the wheel and compound NOT cutting the metal but
pushing it along into the highs and lows. Do you or can you find
again near you any orthopedic titanium hip replacement maker. they
turn the ball end on a cnc lathe the mirror polish for its fit into
the ptfe socket the surgeon machines into the bone of the pelvis, an
engineering exercise if ever there was one!!.

They may have some suggestions others here havnt made. Ie answers
from an INDUSTRIAL user.

Hope this helps and keep us up to date what progress your making.
Just to whet your appetite for titanium, have a think how you might
take a disk some 18in in dia by 1/4in thick of 999 T metal and then
forge it into a constant curve bowl. Then polish it then fire it in a
kiln. thats what I do.

Ted.


#12

Ted, thanks again for your feedback. Interesting work you’re doing
there.

Sean