Black coating on shock jewel metal housing

[MichaelS]

Hi guys,

I am completely new to watch making and currently I am iterating on my cleaning process to get it right. My current process is a 3 step cleaning routine in an ultrasonic cleaner and drying afterwards in a food dehydrator at 45°C.

1. 10min wash with Elma Red 1:9 at 58°C
2. 5min rinse in distilled water
3. 2min rinse in IPA 99%
4. 10min drying in a food dehydrator at 45°C

I have an old ETA 2842 which I use to test the process and the cleaning in general works pretty good...but I found one strange thing during one run I did yesterday.

After the 10min wash cycle in Elma Red 1:9, the bright silver balance shock jewel metal housing colored black.

Do you have an idea what happened here?

Thanks, best regards

Michael

 

[VWatchie]

I use the same liquids but in a vintage Elma watch cleaning machine and have never experienced anything like that. What happens if you rub the housing with a piece of peg wood? Does the black colour come off?

Elma Red 1:9 is ammonia-based. I wonder if ETA perhaps used some special alloy in this particular case that would react with the ammonia. Maybe the 58°C has something to do with it? I only use room temperature which of course is less efficient. Darkening of steel usually happens when subjected to the acid for de-rusting. Well, I'm just guessing.

[MichaelS]

If you rub it with peg wood, it is possible to rub it off...but not easily and not completely - so it's definitely some surface reaction/coating. You can easily scratch it with tweezers. 

Maybe some more information, which could contribute to this situation.

I am putting the bigger plates directly into the jar with Elma Red and I have two brass cleaning baskets where I put the smaller parts (screws, wheels, etc) in. Maybe the brass baskets have something to do with it too?!

My first cleaning trial was with Fairy instead of Elma Red. There I had a similar problem on a different location. I got a black surface coating on a pinion on the second wheel...and some weird rust-like traces on other wheels (I guess that's purely my fault, due to insufficient drying in between ).

So maybe the stuff I created in my first trial...still is in the system and redistribute within the parts?! 

I will try with another movement - without internal black stuff to check this!?

[tomh207]

Maybe it’s something in your water supply? Worth trying mixing the Elma 1:9 with deinonised/distilledwater?

 

just a thought 

 

Tom

[MichaelS]

I used distilled water for mixing Elma and also for the first rinse...so it should not be the water!?

[tomh207]

It was just a variable that possibly could be a problem but you have ruled that out Michael.

 

I don’t have any other suggestions, sorry.

 

Tom

[rjenkinsgb]

The only reaction I can think of offhand where a silver (and non-ferrous) metal rapidly turns black without extreme heat is with actual silver?

If there was any sulphur based material in the liquid, that could possibly produce black silver sulphide/

>google<

OK, looking at the Elma Red safety data sheet, it contains sodium cumenesulphonate and potassium cumenesulphonate.

The silver reaction seems a possibility?

 

If it is that, it can be converted back to silver by bubbling hydrogen over it; hold it over some shredded aluminium foil in a washing soda solution - as long as that will not harm any other part of the plate?

(That's an old trick to avoid taking the surface off tarnished silver or silver plated items when cleaning them).

 

[MichaelS]

That sounds pretty interesting to me!

But this generates some more questions

1) if this is silver sulphide then the jewel housing must be made out of silver right?! Does anyone know for sure which material is used by ETA for this? It was very shiny before...so it would not surprise me. On the other hand....why would I use silver for that, when the pivot never touches this housing?! Would be a waste of money for me?!

2) if this is silver sulphide - do you think it's required to remove it...or can we live with it on the main plate/housing? Actually it's a shock jewel housing...so in my opinion it's only cosmetic and will not influence the performance of the balance?!

[nickelsilver]

That's a really hot bath temperature. I don't recall ever seeing a watch-specific cleaning machine with heat available for the cleaning bath; however ones that have ultrasonic do warm the bath as a result of that. In my ultrasonic tank in which I use a similar product to the Elma, I set the heat to 35 (C), mostly because I don't tend to leave parts in long enough for it to heat from the ultrasonic action. A warm bath does tend to clean better or at least faster than a cold one.
 

I think the ammonia in the Elma has reacted with the plating on the setting at that high temp.

[RichardHarris123]

I think a ten minute rinse in water is too long. 

 

[MichaelS]

Ok maybe that's the case - I was following this recommendation from:

https://watchrepairtutorials.com/ultrasonic-watch-cleaner-how-to-get-great-results/

Here it is described to do the wash at 137 deg-F, which is 58 deg-C and he tested Elma Red with the described cleaning routine (10min wash, 5min rinse distilled water, 2min rinse 99% IPA). 

[VWatchie]

15 hours ago, nickelsilver said:

I think the ammonia in the Elma has reacted with the plating on the setting at that high temp.

That was my gut feeling as indicated in my previous post.

15 hours ago, RichardHarris123 said:

I think a ten minute rinse in water is too long.

The total time in water is 15 minutes which seems too long. I go half that time at room temperature. I go six minutes of cleaning in Elma Red 1:9, less than two minutes of rinsing in battery water, and about two minutes in IPA. Depending on how dirty the movement is I get a fairly good result. For a near-perfect result, I need to pre-clean the parts by brushing them off in a degreaser and then in some IPA.

[rjenkinsgb]

The setting could have been silver plated? I doubt it would be solid silver. 

 

I initially tried various liquids for cleaning, with pretty mediocre results. Eventually I forked out for the gallon-size containers or L&R #111 cleaner and #3 rinse.

That stuff, cold, at three to six minutes a stage in the ultrasonic, works superbly; the results are immaculate even on things that are disgustingly bad when they go in.

 

[VWatchie]

1 hour ago, rjenkinsgb said:

I initially tried various liquids for cleaning, with pretty mediocre results. Eventually I forked out for the gallon-size containers or L&R #111 cleaner and #3 rinse.

Do you use an ultrasonic cleaner or a watch cleaning machine?

I've been considering trying out the L&R liquids you mention in my "ancient" Elma watch cleaning machine.

However, I worry that these liquids are too toxic and smell too much without adequate ventilation. Where I live it is normally too cold to work with this outdoors, but a few months a year it could work.

At some point, I tried Elma's Suprol Pro and almost passed out from the fumes. It comes with a "narcotic effect" warning. How bad are the L&R fluids in this respect?

 

[rjenkinsgb]

The cleaner smells of ammonia, but it's not too bad; just keep it covered as far as practical. 

I use an ultrasonic machine on a kitchen worktop.

The rinse does not smell strongly, it's vaguely like paraffin. I did check the safety data sheets before buying it & it's said to be safe in normal use.

My dedicated watch cleaning machine is still a work-in-progress; four position linear, based on 1L kilner jars for station spacing, to have a heated dryer in position 4.

It uses standard, readily available parts as far as possible to make it easy to reproduce, plus 3D printed bits for the custom parts.

(The horizontal drive motor is out at the moment while working on the stepper drive software)

 

 

[Neverenoughwatches]

2 hours ago, VWatchie said:

Do you use an ultrasonic cleaner or a watch cleaning machine?

I've been considering trying out the L&R liquids you mention in my "ancient" Elma watch cleaning machine.

However, I worry that these liquids are too toxic and smell too much without adequate ventilation. Where I live it is normally too cold to work with this outdoors, but a few months a year it could work.

At some point, I tried Elma's Suprol Pro and almost passed out from the fumes. It comes with a "narcotic effect" warning. How bad are the L&R fluids in this respect?

 

I use elma ammoniated H , the jar remains open for around five minutes while i set the basket up clean and spin off the cleaner. The smell doesn't bother me at all, i do this in a 10 by 8  foot room, but i think I'm immune to most environments . I could open a window or a door i guess but watch repair under the influence of toxic fume inhalation adds to the overall experience. ( just joking peeps dont try this at home ).

24 minutes ago, rjenkinsgb said:

The cleaner smells of ammonia, but it's not too bad; just keep it covered as far as practical. 

I use an ultrasonic machine on a kitchen worktop.

The rinse does not smell strongly, it's vaguely like paraffin. I did check the safety data sheets before buying it & it's said to be safe in normal use.

My dedicated watch cleaning machine is still a work-in-progress; four position linear, based on 1L kilner jars for station spacing, to have a heated dryer in position 4.

It uses standard, readily available parts as far as possible to make it easy to reproduce, plus 3D printed bits for the custom parts.

(The horizontal drive motor is out at the moment while working on the stepper drive software)

 

 

I wish i could do something like this Rob but my thick joiner brain limits me to an adapted drill and drill press cleaner. It seems to clean very well just takes up a little of my time to switch jars around. 

[VWatchie]

27 minutes ago, Neverenoughwatches said:

watch repair under the influence of toxic fume inhalation adds to the overall experience.

Just added this to my quote book! 

[Neverenoughwatches]

5 minutes ago, VWatchie said:

Just added this to my quote book! 

Ok but in no way am i endorsing the practice, it is purely for my own watch related pleasure

[ColinC]

That black stuff - I had similar things happen with evaporust!  In that case I understand the evaporust eats the iron oxide away without hurting the metal but it can leave behind a layer of carbon which was in the steel that got oxidised.


I spent ages trying to perfect a cleaning regime with various different stages in jars in an ultrasonic bath. In the end I switched to washing all but the balance and pallet fork in IPA and gently brushing it with a small artists brush.  I would estimate that I have found an extra 20º of amplitude doing this!

It also takes me no longer than waiting hanging over a tank to move stuff to the next jar

If it is really bad then I have used the IPA as a prewash and go through my old routine

Edited May 20, 2024 by ColinC