Polishing dial marker

[gkmaia]

Hi, I am new to the forum and to watchmaking.

I am practicing polishing and wanting some guidance on how to make the best with the tools I have.

One thing I would like to practice is polishing the dial markers to a mirror finish.

I've tried a few things with not much success.

Wood stick embedded with bergeon diamond powder mixed with oil produced some deep scratches and a dull finish. Wood stick embedded with 1 micra paste produced less scratches and a dull finish. Should be embedding the paste directly to the wood or to cotton or leather? How much pressure should I make while polishing?

I got a pretty good shine without scratches using a dremel and the pink polishing pad. But because it does not allow for much precision I ended rounding the edges.

Could anyone give me hints on what to use and how. And what to expect to see after a given time polishing?

 

[oldhippy]

Thank you for your introduction and welcome to this friendly forum.

Have a look at this which is on our forum. This is other members advice.

 

 

[gkmaia]

Thanks. I appreciate the answer.

I guess it does not really help. The post talks mostly about cleaning a dial.

I don't really care about the dial I am working on as it is just for training. Not trying to restore it. But that maker was once polished to a mirror finish. That is what I want to learn. How to black polish that marker, which has awkward angles, to a mirror polish back again. 

Or the only way to achieve those angles and finish is by traditional black polish with a flat zinc plate? 

 

 

 

 

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Thank you for your introduction and welcome to this friendly forum.

Have a look at this which is on our forum. This is other members advice.

 

 

 

[rodabod]

Any idea what the markers are made from? Plated?

My choice for stainless markers is a minuscule amount of Autosol on peg wood. 

[gkmaia]

thanks rodabod. 

For stainless how much pressure do you apply? and after how many minutes I should see some improvement?

If it is plated what technique would you choose? I imagine it will be diferent for gold or nickel for example as their hardness differ. 

Compared to bergeon powder, does autosol has a higher grit value?

[rodabod]

Hi, I would only polish solid, unplated markers. 
 

For how long? That’s not really an easy question to answer. Usually not long at all. 
 

Autosol is a blend of abrasives, but importantly it contains silicon carbide (or silicates of some sort... I can’t precisely remember) which means that it cuts very fast. 

[gkmaia]

You would not polish plated parts because of the thickness of the plating layer? It's hardness? What is the reason?

If it was a gold or nickel plated case with light scratches would you polish it? Or sand it and re-plate? 

 

[jdm]

3 hours ago, gkmaia said:

You would not polish plated parts because of the thickness of the plating layer? It's hardness? What is the reason?

If it was a gold or nickel plated case with light scratches would you polish it? Or sand it and re-plate? 

As a general rule, it's not possible to polish plated parts for the obvious reason that  plating will be gone before any polishing is done. At most, some superficial cleaning could be possible with a ligth hand and a very mild abrasive. 

I suggest that you learn the basics of polishing working on larger parts and why not, plated ones to experiment and see yoursef what can and cannot be done. 

Also, sanding is rarely a good approach for watch parts because it's difficult to apply uniformly and leaves a way too rough surface that then takes a long time to be smoothed.

Substantial plating is best removed by (electro) chemical stripping, which is also an art and science in itself, e.g.

https://www.pfonline.com/articles/stripping-of-plated-finishes

[gkmaia]

Thanks so much for your feedback. Understood about the plating and it makes total sense. 

I am doing some experiments on a pair of hands.

On the hour hand I spend probably 15min of light circular movements using bergeon diamond powder and a bare wood stick. That has got pretty close to mirror but left many scratches. Then another 15 minutes using the same powder but I glued a piece of leather on the other end. Light circular strokes. Got much closer to mirror, but still left with some scratches. It takes much longer with the leather but seems to provide a much more delicate finish.

I am avoiding cross contamination of my bergeon powder stick with my other abrasives, but still getting those scratches from the bergeon powder. Am I putting too much pressure? What could be causing that? Cross contamination? 

 

[gkmaia]

My best result so far. The brass hand was pretty nasty with oxidation. I did 5 min of wood and 5 micra, then 5 min of leather and 5 micra. Then moved to bergeon powder with wood for 5 min. Then bergeon powder with leather for 4 min. For the bergeon I tried different levels of pressure and got no scratches. Bergeon grit appears to be extremely fine. 

The stainless movement plate I started with  40 micra. The did the same I did with the hand. Most of the large 40 micra scratches remained but the final mirror polish started to show as well. 

So anything above 5 micra seems to leave scratches that takes ages to smooth with diamond powder. 

I will try the other side of the plate to start with autosol, then powder to check if grit is higher than 5 micra.

Am I on the right track? Any other tips?

[rodabod]

It’s possible that you could be getting contamination which causes scratches, or perhaps you’ve just got relatively deep scratches in the first places which are hard to remove. 
 

Brass can be quite difficult to polish by the way. You may assume the opposite because it is softer than steel, but it can be quite tricky. 
 

A few things that I think are worth mentioning: 

The harder your polisher, generally the harder it will cut. I think you’ve already pointed that out with your leather polisher. Some metals work well as polishers (like tin) but would not use one for polishing hands. Peg wood works well for hands. 
 

A hard, flat polisher will help you achieve flat surfaces and sharp edges. You need to watch out when using something soft that you don’t overdo it and soften the edges. 
 

On larger pieces, it makes sense to change your orientation of polishing between grades/grits by 90 degrees so that you can prove that you have removed the scratches from the previous grade entirely before advancing to a finer grade. 
 

Sometimes on smaller flat pieces it can help to polish “under hand” to help keep the polisher parallel to the work. So for example, you could get a flat block of boxwood, smear it with a small amount of abrasive, and then rub the part to be polished on the flat block. 

[gkmaia]

That is super helpful. 

I've been trying to do cutting steps within 90 degree angles so I can see if I still get a scratch from which step it come from and then the final powder one in circles.  I also noticed what you mentioned about cutting the edges with something soft. 

But that was supper helpful. I am getting more confident on how each abrasive work. 

I will plate a small brass plate with nickel plated part and test removing scratches from it. See what it takes to get through the plating layer.