What the heck are these hard green flakes on the movement?

[GregG]

I opened an antique pocket watch today, and after taking off the dial, I found that it was covered in these hard green flakes.

The flakes were so thick that I think the previous person who serviced it placed 5 dial washers to evenly lift the dial off the dial plate.  That also had the added bonus of making the dial sit so high that it was nearly impossible to get hand levers under the hour hand.

I was able to get most of it off by scraping.  But as shown in the picture, there was still a lot left on the dial plate.  I thought perhaps it was shellac, despite the fact that shellac is reddish brown, not green.  I soaked it in acetone and it did not dissolve, however, the major chunks on the dial plate all slid off in one piece.  So I don't know if it was because of the acetone, or simply because it was wet and that loosened it up.

Anyone have an idea?

 

[grsnovi]

Without being able to touch/feel the flakes, my first guess would be dried, desiccated oil. My second guess would be dried, desiccated sugar syrup.

Do you know anything of the watches history?

[GregG]

13 minutes ago, grsnovi said:

Without being able to touch/feel the flakes, my first guess would be dried, desiccated oil. My second guess would be dried, desiccated sugar syrup.

Do you know anything of the watches history?

Unfortunately no, it's a purchase off of eBay.  Maybe the owner tried to glue the dial to the dial plate or something.

[grsnovi]

Glue is another probability (probably more likely than sugar syrup).

 

[Shane]

My guess is dried oil.  Dried plant or animal based oil.  The fatty acids probably attached the brass and dissolved some of its copper.  It could explain an emerald green color.

I had a wall clock full of that stuff.  It was virtually indestructible.

Don't let children or animals interact with it, copper compounds are usually poisonous.

Shane 

 

[grsnovi]

@GregGIt would be interesting to do some experiments (if you still have any of the flakes).

Do they dissolve in:

• water?
• IPA?
• oil?
• naphtha?

[GregG]

7 hours ago, Shane said:

My guess is dried oil.  Dried plant or animal based oil.  The fatty acids probably attached the brass and dissolved some of its copper.  It could explain an emerald green color.

I had a wall clock full of that stuff.  It was virtually indestructible.

Don't let children or animals interact with it, copper compounds are usually poisonous.

Shane 

 

Hi Shane, that seems like a reasonable guess.  Per @grsnovi's comment, I will try to soak it in a few things to see what dissolves it.

[spectre6000]

My money is on glue. More specifically, hide glue. Predates a lot of the modern glues, used to be very common, works with metals (and even glass), dries hard and crystalline/glasslike, slightly brown (like caramel) if it's thick enough, pretty much clear if it's thin, and is acidic (would leach copper from the brass). It is water soluble (you'd have to crunch it up into small pieces/granules, and it'll take a while), and melts at... 180*(? I have a pot for hide glue for luthiery that just gets to the correct temperature without me having to remember...) for reworking. It has a distinct smell, but if it's old it might not smell much unless it's melted down and reset.

Edited October 31, 2022 by spectre6000

[grsnovi]

@GregGYou might add melting to your experiment...

 

[GregG]

14 hours ago, grsnovi said:

@GregGYou might add melting to your experiment...

 

Unfortunately I don't have a hot plate, and I don't think the wife would be too happy about me running experiments on the stove.    Boy oh boy did I hear it when I tried to make a nickel plating solution under our stove's fume hood.

Edited November 1, 2022 by GregG

[GregG]

So I tried searching the garbage can for a scrap of the mystery substance but couldn't find anything suitable.  Sorry guys, I think this one goes down as an unsolved mystery.