Silvering recipes

[jdm]

These have been passed to me by a distinguished forum member that is too busy to post at the moment - he's working on a mov. t so small that all its sizes are actually negative numbers. 

I have a couple. Both work, the second one seems to be more forgiving in use. They both contain: silver nitrate, cream of tartar (potassium bitartrate), and regular salt, and the second one has a little alum (potassium alum).

The combinations are by weight.

1st formula:

1 part silver nitrate

2 parts cream of tartar

2 parts salt

 

2nd:

1 part silver nitrate

8 parts cream of tartar

8 parts salt

2 parts alum

As you can see the first one has a far heavier concentration of silver; in my experience the silver deposits very quickly and builds up thick areas before an even colored coating is achieved. At a certain point it just starts to flake off. The second one takes a bit more time to apply, but seems to really get a better, more even covering, which has proven to be quite durable. The mixtures are made and stored dry. I grind up the salt in a mortar to get it as fine as possible. To apply, you make a paste with water (doesn't seem to matter if it's tap or distilled, but chemically it probably does a little bit), and then just rub it around on the brass until you have a nice even coat. Rinse off, then rub all over with wet cream of tartar, rinse, dry, then lacquer.

I've seen probably half a dozen other mixtures, some using silver chloride (which actually gets made here with the salt if I'm not mistaken), some just with varying proportions. So it's not terribly fussy.

 

[praezis]

The first recipe is used for "graining", the appearing uneven surface is deliberate. The paste is applied with a brush.

You can see this grain on many pocket watch movements. It was the traditional preparation before gold plating.

Frank

[spectre6000]

I had something to do with the above message, but I assure you am not the distinguished forum member being quoted. I have a handful of silver plated watch cases. I borked enough of the movements learning that I'll have some spares for experimentation. It's my intent to take a swing at both recipes and document the process and results. I was initially thinking two cases, but it sounds like a third may be in order.

Can you elaborate on the graining? Is there a process/technique that goes with it, or is that just the natural result of the application? Can you provide any photographs of examples of this having been used?

There is also a liquid solution I've seen sold commercially. I very much prefer to "roll my own" (as we say in the software world), and for the cost that's probably the route I'd take. I'm not bad enough to have four test cases (I don't think I have three either, but we'll see), but may dig out a case or two that I borked something with bad enough to decide the case is worth experimenting on. Are there any base metals or platings that these won't adhere to?

[praezis]

35 minutes ago, spectre6000 said:

Can you elaborate on the graining? Is there a process/technique that goes with it, or is that just the natural result of the application? Can you provide any photographs of examples of this having been used?

As mentioned, it is applied with a brush. There is a moment for the right result, not too short and not too long. However I know it from literature, never did it myself, though I planned to and have the ingredients in stock (silver powder, cream of tartar). For silvering small parts I use a commercial liquid product.

Frank

[LittleWatchShop]

Hey, I am gonna jump on this thread with a question about use.

In the picture, you see a Landeron 51 chronograph, case, and pushers.  It is running very well now that I have a new hairspring. I plan to find some hands and either buy a dial or have this one refinished.

As far as the case and pushers...is that silver plating, or chrome?  I realize I am asking for a guess since you cannot investigate in person.  Maybe using this silver process you guys are talking about would work??

I would like to restore to a pristine condition.

[spectre6000]

It's almost certainly not a silver plated case. It's not a really great option for cases because it tarnishes. The watches I have to experiment with were NOS from the early 70s, and they were splotchy black. Tarnished silver doesn't look good, and needs frequent polishing (or handling) to avoid tarnish. Plating wears through quickly. Chrome and nickel are the more likely plating materials.

The dial on the other hand... If that's a silvered dial, check out this thread:

Ignore the beginning of the thread, and scroll down about half way (look for the photos).@Blacklabshows a dial he cleaned up using what I believe is the commercial liquid solution. It might be a good way to bring that dial back. The applied details will still be missing where they're missing, but it would likely clear up considerably without all the noise from the missing silver and tarnish.

Edited February 18, 2021 by spectre6000

[praezis]

As spectre already mentioned, surely no silver on the case. 

If the case shows pitting: it is chrome.
With no pitting at all: most probably Nickel. 
Nickel is slightly yellow, chrome more blueish-white.

Frank

 

[spectre6000]

OK.... I finally got everything required to do this. Silver nitrate is pricey, and not the easiest thing in the world to find. Simultaneously, way easier than I thought it would be to get once found. The lowest price I could find online happened to be a local outfit just below me in the flats! 

My silver nitrate is very coarse (one crystal looks to be nearly a cc all on its own), and I understand it can be some nasty stuff. Gloves and a mask for sure. I think I'm going to do my best to grind it to a fine powder, then put it back in its jar. The alum and tartaric acid are already very fine. Salt will need to be ground too, but I can get close enough and won't feel guilty tossing any extra. 

From there, I figure parts by weight? Pre-mix the silvering powder, and leave the rest of the silver nitrate in its bottle. 

Then... Um... Wet a q-tip, dip it in the powder, and rub it on? Maybe just the finger of a glove? Polish cloth? What's the deal here? Has anyone actually done this before? Any pointers?

Also, anything particular about the lacquer? Rustoleum work, or blonde shellac? I have both, and can get some third option should that be the preferred solution.

Edited August 17, 2021 by spectre6000

[LittleWatchShop]

On 8/16/2021 at 9:38 PM, spectre6000 said:

OK.... I finally got everything required to do this. Silver nitrate is pricey, and not the easiest thing in the world to find. Simultaneously, way easier than I thought it would be to get once found. The lowest price I could find online happened to be a local outfit just below me in the flats! 

My silver nitrate is very coarse (one crystal looks to be nearly a cc all on its own), and I understand it can be some nasty stuff. Gloves and a mask for sure. I think I'm going to do my best to grind it to a fine powder, then put it back in its jar. The alum and tartaric acid are already very fine. Salt will need to be ground too, but I can get close enough and won't feel guilty tossing any extra. 

From there, I figure parts by weight? Pre-mix the silvering powder, and leave the rest of the silver nitrate in its bottle. 

Then... Um... Wet a q-tip, dip it in the powder, and rub it on? Maybe just the finger of a glove? Polish cloth? What's the deal here? Has anyone actually done this before? Any pointers?

Also, anything particular about the lacquer? Rustoleum work, or blonde shellac? I have both, and can get some third option should that be the preferred solution.

So, did you ever do this?  How did it go?  I am pondering doing nickel plating instead??

[Jack75]

This is the commercially available mix:

https://www.cousinsuk.com/product/dial-silvering-powder?code=S1524

But I prefer to use magic Rhodium for restoring brassed parts.

https://www.cousinsuk.com/product/magic-rhodium

[spectre6000]

I haven't yet. Lots of irons in lots of fires. I keep thinking, "I'm going to do it this weekend", then Monday morning I think it again. We're rushing to beat winter on a number of things on the house. Hopefully things settle down a bit once the snow starts flying.

Edited October 17, 2021 by spectre6000

[LittleWatchShop]

On 10/16/2021 at 3:12 PM, Jack75 said:

But I prefer to use magic Rhodium for restoring brassed parts.

OK.  It arrived today.  How do I use it??

[LittleWatchShop]

11 hours ago, LittleWatchShop said:

OK.  It arrived today.  How do I use it??

Shake it up and rub it on with pegwood. Hmmm...not seeing the effect I expected.  Will continue to research and experiment.

[spectre6000]

If it's like the silvering, what I see people doing is using cotton balls. I was planning to try with q-tips personally; seems easier to get into corners.