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Polishing Results

jdrichard
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jdrichard Distinguished Member

jdrichard

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9 minutes ago, KarlvonKoln said:

Indeed yes!  A fine job of it.  What materials and methods work best for you?

New polishing motor with three pads, progressively finer.  use Stainless steel polish lightly on the first pad and fine blue on the last pad.  seems to work well.  maintain heat through pressure to melt the metal into itself....an art that gets better with practice.

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jdrichard Distinguished Member

jdrichard

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16 minutes ago, Klassiker said:

Hard to imagine a better result than that!

What do you mean by this?

to buff out all the scratches, you are in fact not removing material, you are melting the high points into the low points.  Friction + heat and that is how it is done.  Works great on Stainless Steel watches and this is an Omega pocket Watch with a Silveroid metal, which is in fact a Nickle Copper compound.

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HectorLooi Distinguished Member

HectorLooi

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3 hours ago, jdrichard said:

to buff out all the scratches, you are in fact not removing material, you are melting the high points into the low points.  Friction + heat and that is how it is done.  Works great on Stainless Steel watches and this is an Omega pocket Watch with a Silveroid metal, which is in fact a Nickle Copper compound.

I think this is a misconception perpetuated by one YouTube video on polishing. Nowhere in material science literature have I come across this explanation.

Silver melts around 900°C and stainless steel around 1300°C. If the friction is enough to cause the surface to melt, the polishing mop would burn.

Burnishing can move material from high spots to low spots by plastic deformation. You have demonstrated that in many of your pivot polishing videos. But the forces involved in burnishing are much higher. The force generated by pressing an object into a buffing mop cannot generate sufficient force to move metal molecules. 

When polishing thermoplastics like acrylic, if too much pressure is applied until it melts, it never a good thing. The mop would gouge out the softened surface.

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jdm Distinguished Member

jdm

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On 4/2/2021 at 12:43 AM, HectorLooi said:

I think this is a misconception perpetuated by one YouTube video on polishing. Nowhere in material science literature have I come across this explanation.

I suppose the video to which you referring is the following, by a reputable American watchmaking school

Quote

Silver melts around 900°C and stainless steel around 1300°C. If the friction is enough to cause the surface to melt, the polishing mop would burn. 

Burnishing can move material from high spots to low spots by plastic deformation. You have demonstrated that in many of your pivot polishing videos. But the forces involved in burnishing are much higher. The force generated by pressing an object into a buffing mop cannot generate sufficient force to move metal molecules. 

This discussion has been done on our forum already in the past. I do not have anything to object to the physics explanation and tests done to say that buffing cannot move material. My only point, then and now, is that in practice with buffing one can acceptably repair some damage without excessive abrasion or micro-welding.

That comes not only from my personal experience, as the Master in the video above and many other repairers share my same opinion - it just works. If you haven't ever tried it I recommend that you do. Case restoration is very rewarding and in demand.

 

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jdm Distinguished Member

jdm

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7 minutes ago, dadistic said:

Oh boy. When I first saw this claim about melting metal on the video from perplxr I almost choked on my coffee. 

He never used the verb melting, if he did I didn't catch that. 

Just curious if you have ever done any sort of similar work yourself?

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dadistic Distinguished Member

dadistic

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Not watch case polishing, but in machining surface finish can be a big deal. We have had to get some gnarly micro finishes at times. We have engineers that understand this very well. Also, at one time I had some exposure to the manufacturer of lapping machines that were used for polishing the silicon wafers used in semiconductor manufacturing (my friend worked for them, and we discussed the tech a lot). Probably the most exacting surface requirements there are, and there was no melting involved ? I used to have some test wafers that I got from him, they were quite something, but I don't know what happened to them. Was quite a few years back. Actually, at this point, everything was quite a few years back ?

The oversimplified rule is that it is the size of the scratches that matters when creating a finish. But don't take my work for it, ask an engineer who has experience in this area. 

Cheers! 

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jdm Distinguished Member

jdm

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6 minutes ago, dadistic said:

Not watch case polishing, but in machining surface finish can be a big deal.

Your answer is a lot like the ones that went into the other long topic on the subject - sorry I could not find it yet. Someone which had a machine shop (or hobby ?) went to measure with a micrometer the abrasive effect of buffing some deep gauges he did to some metal. No surprise, it was abrasive, nobody claims otherwise.

But this type of repair has nothing to do with theoretical metallurgy, machining or other craft or science. It is just about using a motor (even a rotary tool works to some degree), a felt wheel and a compound of some sort. Get a stainless steel case with some scratches or dings, and buff it staying away from edges. Start with minimum damage, find how much damage you can actually repair without creating visible valleys or the like. Report here if you like. 

 

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jdrichard Distinguished Member

jdrichard

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On 3/31/2021 at 8:03 PM, PeterS said:

I'll be starting on the Waltham pocket watch this weekend.
You've already advised me that I can't wind the mainspring via the ratchet wheel and helped me with oiling.

This is my first pocket watch and I'm more used to the more modern movements. I would appreciate if you could let me know what to watch out for, what to be careful with etc. Stuff that differs from wrist watches.

Couple of questions:

Do I need to unscrew the jewels from the bridges? I will have to remove the jewel from the balance to clean it properly but I'm not certain about the other jewels. I presume that It will be straight forward putting them back?

Is the crown wheel screw reverse threaded?

Detaching the crown, is there a chance I may strip the tread on the stem?

Pictures of the jewels and the movement are below.

 

P3311014.JPG

P3311030.JPG

P3311094.JPG

 

25 minutes ago, dadistic said:

Not watch case polishing, but in machining surface finish can be a big deal. We have had to get some gnarly micro finishes at times. We have engineers that understand this very well. Also, at one time I had some exposure to the manufacturer of lapping machines that were used for polishing the silicon wafers used in semiconductor manufacturing (my friend worked for them, and we discussed the tech a lot). Probably the most exacting surface requirements there are, and there was no melting involved ? I used to have some test wafers that I got from him, they were quite something, but I don't know what happened to them. Was quite a few years back. Actually, at this point, everything was quite a few years back ?

The oversimplified rule is that it is the size of the scratches that matters when creating a finish. But don't take my work for it, ask an engineer who has experience in this area. 

Cheers! 

I did take Strength of Materials in Engineering University, but then went on the Electrical Engineering where the only thing you melt is circuits by to much power input:) I will need to ask my son the Mech Eng.  I like the melting explanation as it seems to make some sense, however, if the melting point of SS is really high, the question is can it get pliable enough to move.

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HectorLooi Distinguished Member

HectorLooi

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Looks like JD brought it out and I reopened the can of worms.

I've polished all sorts of stuff. From soft stuff like wax, plastics, resins and 24K gold. Metals like aluminium, copper, brass, bronze, silver, gold, steels, stainless steels, nickel alloys, tungsten carbide. Hard, brittle stuff like glass, ceramics, zirconia.

I think we've all polished stuff and our personal experience guides our thinking. Some arguments can never be settled so lets just end it here and remain friends.?

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jdrichard Distinguished Member

jdrichard

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12 hours ago, HectorLooi said:

Looks like JD brought it out and I reopened the can of worms.

I've polished all sorts of stuff. From soft stuff like wax, plastics, resins and 24K gold. Metals like aluminium, copper, brass, bronze, silver, gold, steels, stainless steels, nickel alloys, tungsten carbide. Hard, brittle stuff like glass, ceramics, zirconia.

I think we've all polished stuff and our personal experience guides our thinking. Some arguments can never be settled so lets just end it here and remain friends.?

I’m good with that:) I do have a question however. Does anyone know where the guy in he “perplxr “ video got the framed loupe that he is wearing in the video? It goes around the circumference of the glasses to hold the flip-down loupe on the top.

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