Serious verdigris corrosion on Schatz JUM/7

[AndyDWA]

On a recent interstate trip, I picked up this poor little thing for $10. I couldn't return home without a 400-day clock and this was the only one available in my price range.

I can't imagine how it got in this state but it has the most-serious corrosion I've seen to date on any clock. Other than the barrel, the gear train looks to be in pretty good condition.

I'm assuming I will just dismantle it and set to work with a toothbrush, followed by lots of polish and wax. But is there a "correct" way to deal with this? Do I need to neutralise the verdigris or anything? Will it ever stop?

I have no professional equipment, like ultrasonic, just domestic chemicals, steel wool, various brushes, Autosol and carnauba wax.

I am a little worried about the bottom-left screw on the back plate. It looks ready to disintegrate.

I am yet to see inside the barrel and expect I may need a new spring (and maybe a replacement barrel), but can I win or are my expectations too high?

 

[THTanner]

Looks like something that had been sitting on a ship in a salt water harbor for awhile.

 

[AndyDWA]

Yes. I used to have coral reef aquaria some years ago and this looks like the sort of thing that used to grow on the glass

I checked today and it doesn't wind. So either the spring or the hook is likely broken.

 

[victor miranda]

that is quite the project.

the corrosion will be spots and circles in the brass when you have
it mostly removed.

I expect you will need to repivot at least a few arbors.

I am very fond of Jum/7 clocks and I think you should consider it as parts.
when you find the proper dome for it, you are very likely to get a clock under it.

I'd clean it as practice and to stop the erosion.
:-D and then you will have a cute 'basement clock'

victor

 

[sjaffe]

A mixture of baking soda and water may help to neutralize the corrosion.
Stan

 

[shutterbug]

Wow! Maybe it fell into a salt water aquarium at some time in it's life.

 

[THTanner]

I was just about to type that perhaps it would make a fine piece or "flotsam" on the bottom of a big aquarium

Wow! Maybe it fell into a salt water aquarium at some time in it's life.

 

[Dave T]

I definitely want to see this one when you get it restored. Sounds like an ambitious project.

 

[Harry Hopkins]

I was taught to always find something nice to say...

"The dial is nice."

just kidding... good luck and show us pictures as it progresses.

 

[KurtinSA]

Tinker had a detailed discussion about a corrosion situation in this thread:

https://mb.nawcc.org/showthread.php?140568-Anyone-familiar-with-1966-Seiko-Photo-Electronic-(Solar-Clock)

Maybe this will help to figure out how to proceed. Maybe a different type of corrosion...don't know.

Kurt

 

[AndyDWA]

Thanks all. It did come with the original dome and is worth at least $10 in parts so I'm okay with it as a purchase - and as a project.

We already have a JUM/7 without that little plastic suspension bracket guard so, if nothing else, we now have one of those

Perhaps the most amazing thing about it is that the enamel on the base is in pretty good condition. It's weird to see all the corrosion inside the dome, not outside.

 

[Tinker Dwight]

It is almost as though someone sprayed something on it.
I once accidentally sprayed white grease on a balance wheel
then I intended to spray brakekleen.
I found out that even brakekleen doesn't remove white grease.
Maybe hair spray or maybe even windex window cleaner.
If you knew a chemist, you might have it analyzed.
Tinker Dwight

 

[MartinM]

I think this is an example of dezincification:
https://en.wikipedia.org/wiki/Selective_leaching
Probably brought on by the clock sitting on a metal stand in a high humidity area that introduces a galvanic response not only in the dissimilar metals but the alloys, as well.
That. or it was sitting for a long time near a saltwater rheostat or Himalayan salt lamp.

 

[Tinker Dwight]

It was clearly something that was put on the clock movement.
One wonders if it might have been someone that read one of
R. Feynman's stories about getting a clock to run with soap.
The spots on the drum are from drops of something.
Tinker Dwight

 

[AndyDWA]

Started dismantling and was going reasonably well until that rusted backplate screw sheared off. I'm not sure how I'll remove the thread without pro tools.

I am unable to separate the plates so far. I think one or two pivots are rusted in place, holding it all together tight.

I'm thinking of soaking the whole movement in a mix of lighter fluid and light oil to see if it will penetrate the tight spots. Or hitting it with doses of WD40.

Since most of the corrosion is to one side, I guess it's possible it was sitting uncovered on a bench while something else was being sprayed with something. Maybe the person realised then covered it, without cleaning it up, then left it covered and wet.

 

[Tinker Dwight]

It might be better to soak it in vinegar before putting things that water
doesn't like.
Tinker Dwight

 

[BLKBEARD]

Try a piece in a vibratory case polisher. If you don't have one, any friend who is into ammunition reloading will have one. https://www.youtube.com/watch?v=SGeUF1IEhOw

Such as this. It cleans with crushed walnut shells, and is specifically made for brass.

 

[AndyDWA]

Using intermittent combinations of alcohol and vinegar, I have manged to separate the plates.

Total casualties include: One backplate screw, one dial-collet grub screw and two pivots.

At this stage I can only image how I might replace a pivot in a midget escape-wheel arbor so it may be a while before any real progress is made.

The mainspring actually looks to be okay (I am yet to remove it from the barrel), so I think the winding issue may have related to the click not engaging properly.

 

[victor miranda]

OOOOoooo!
an opportunity to show off!

I have to go take a photo.

 

[MartinM]

To deal with the sheared backplate screw, search the Message Board for "Alum". There are a lot of discussions about using a highly concentrated Alum and water solution to dissolve steel from a threaded brass hole.

 

[AndyDWA]

Interesting. I was going to try and make an "easy-out" but if I can find some alum that might be a less-risky option.

 

[Harry Hopkins]

Interesting. I was going to try and make an "easy-out" but if I can find some alum that might be a less-risky option.

I recently used alum to remove a broken pin from a pin pallet anchor. It worked better than my expectations. I mixed it with a heavy concentration of alum in hot water. I would stir it around a few times a day and once in a while I would heat up the concentration again. After a few days I set up the anchor in my mill to drill out the remaining pin and there was nothing left... the drill had no resistance at all. I found the alum with the spices in my grocery store.

 

[marylander]

Interesting. I was going to try and make an "easy-out" but if I can find some alum that might be a less-risky option.

Andy, Alum can react with steel but not much with bronze or copper. I used Alum to dissolve broken screws from the front plate. It only discolored my front plate but not taking any off noticeable. I got Alum from my grocery store.
Ming

 

[Harry Hopkins]

I had some discoloration on the brass that was submerged in the solution but it polished off. The steel parts that were NOT submerged showed some light tarnishing after a few days from the fumes I suppose but they cleaned up easily also.