Ultrasonic bath cleaners - silver tarnishing

[ScottBouch]

Dear all,

(not sure if this belonged in workshop equipment or here).

I recently bought for Christmas a small ultrasonic cleaner.

I've so far used it to clean up disassembled Mk.4 connectors. This consists of general grime on the aluminium body, old solder flux on the Bakelite insulator, and tarnishing on the contact silver plating.

I just used some neat IPA as the cleaning fluid.

The general grime and flux came off brilliantly. Removing silver tarnishing involved me taking a rag wet with IPA and polishing it off after a good ultrasonic session, this only worked on male contacts, female ones I used an interdental brush and IPA.. I'm trying to avoid abrasive methods so as not to affect the silver plating.

Can anyone recommended other fluids to try with it to remove silver tarnishing? I had a go with cider vinegar on the silver tarnishing, but unsure if this would affect/eat the silver plating, so didn't push ahead with it. It would be nice to find a fluid that did all the work in the ultrasonic bath, save the manual scrubbing/polishing process

Cheers, Scott

[Keith956]

Originally Posted by ScottBouch

Dear all,
Can anyone recommended other fluids to try with it to remove silver tarnishing?

If I recall correctly, 'Silvo' which we used to use to clean silver plate, contained ammonia. So a dilute solution of that may work.

[ScottBouch]

Thats great advice thanks, I've now looked into ammonia specifically with silver and it turns out its a commonly used remedy for silver tarnishing...

Plenty of vague nonsense websites, but this one is not too bad regarding technicalities: https://www.livingbyexample.org/ammonia-to-clean-jewelry/

[McMurdo]

Years ago we bought a perforated aluminium plate which was placed at the bottom of a bowl of warm, weak washing soda solution. A quick dip of anything silver in the bowl, and contacting a part of it to the perforated plate made the silver blackening disappear almost instantly - some sort of electrolysis no doubt!

[Uncle Bulgaria]

There are numerous ultrasonic cleaning solutions available from Cousins. Perusing a watch repairers' forum will also net you various homebrew recipes. Ammonia is commonly used as a brass brightening ingredient, so ammoniated solutions are common.

I think it's not advised to use flammable liquids in an ultrasonic cleaner. I fill mine with water, then place the item to be cleaned in a jar or bag of the fluid I want to use and operate the bath. That way I can clean things from watch parts to car parts in the same bath without having to change the liquid or get it dirty.

[ScottBouch]

Thank you guys, I can try the aluminum trick, I have some perforated aluminum sheet (air grille stuff).

In order to economize the amount of IPA used, I also used a small jar (chilli flakes to be exact!) sat in water in the main bath.

I have realised that this cheap bath has no heater, is this normal? I just assumed that heating would help.

[Cobaltblue]

Discussion about the Ultrasonic cleaner itself must be carried out in MT not this thread.

Only the vintage parts and the cleaning materials used can be discussed here.

Cheers

Mike T

[kalee20]

I've used Goddard's Silver Dip to clean tarnish off silver contacts. It works well.

Another you might try - get some sodium thiosulphate crystals and dissolve in water. The solution does not attack metallic silver, but does dissolve many silver compounds - such as the tarnish!

[David G4EBT]

Another vote for Goddard's 'Silver Dip'.

I've used it for decades - it works a treat:

https://www.amazon.co.uk/s?k=silver+dip&adgrpid=117427931739...tag=mh0a9-21&ref=pd_sl_8nkxvy2siv_e

[TonyDuell]

Originally Posted by kalee20

Another you might try - get some sodium thiosulphate crystals and dissolve in water. The solution does not attack metallic silver, but does dissolve many silver compounds - such as the tarnish!

Commonly known as 'hypo' and used as a fixer for photographic films (because it dissolves the unexposed silver salts but doesn't touch the silver image). A company selling traditional photographic processing chemicals should have it.

[ScottBouch]

Hi all, I bought some Goddard Silver Dip, and yes, it is really good!

I tried it on some contacts from Plessey Mk. 4 connectors. I initially gave them an ultrasonic bath in IPA to remove dirt ans crusty flux, then a soak in silver dip, followed by a further clean with IPA to remove any residue. Finally a coating of Servisol contact cleaner to hopefully stave off futire tarnishing under a layer of whatever that leaves behind.

Mixed results.... Some contacts were slightly different from the others, and had a much brighter finish, these now look remarkable. Some of the other ones appear to have a bit of a pitted/rough surface, I don't know if I damaged them by leaving them too long in the silver dip (there is no warning against damge) or if they were just pretty 'had it' before I started. The tarnish is gone, but the metal finish looks worse than before.

These images show before and after cleaning (before any contact cleaner was applied).

[G6Tanuki]

That looks like a good outcome! I have a bunch of old SO239 sockets and the Burndept type of coax connectors that were used on military gear in the 50s that are all a bit skanky, perhaps they will be having an appointment with Mr Goddard's restoration dip in the near future?

[Vintage Engr]

I've been using Silver Dip for many years, on silver-plated switches, sockets, in fact most things silver that have tarnished.
I am exceedingly careful on wafer switches, as obviously one does not want the cleaner soaking into SRBP wafers. I always use it sparingly, & apply it with a squeezed-out cotton bud.
Once the cleaner has done the job, I then remove all traces using proprietary switch cleaner or IPA, depending on the item.

I have never had a problem after using it, but one does of course need to be careful.

David.

[ScottBouch]

Thank you, I did wander off and leave these contacts submerged for about 10 to 15 minutes..., if the grotty finish on some is due to this long time, then maybe I should have been a bit more vigilant. But it could just be that under the tarnish the finish may not have been great anyway.

Its a learning curve, i'm not into being wasteful, but luckily I have a lot of Mk. 4 connectors, so will try again, perhaps more delicately with your method of using a cotton bud.

I'll try polishing up the grotty looking ones to see if the finish can be improved/recovered.

Cheers, Scott

[ScottBouch]

I just had a quick go at the worst looking contacts.

I tried wiping them with silver dip, and the grotty finish came off.

I'm no chemist, and we don't know what's in Silver Dip, but it's almost as if the tarnish left one item and was deposited on another, like some form of electrolysis may be going on.

But the end result is indeed a contact that looks more brass than silver. I think over-cooking it submerged in the silver dip may have been detrimental to the thin silver plating.

Cheers, Scott