Ideas to chemically darken a pair of yellow gold hands to go on a rose gold watch?

[kaan]

Hi,

This is for a personal project, it's impossible to find rose gold Omega hands so I bought discarded yellow gold hands in a fitting style and I want to darken them a bit through a chemical process so they look like oxidized rose gold hands

So far I tried putting an experimental gold plated buckle into a 1% bleach solution, but can't say I see any results (google's suggestion)

In the past I placed a gold coated crown into an alum solution to dissolve the broken stem inside, however assumably since the local alum had a different compound than the western watchmaker's use, it darkened the yellow gold crown quite a bit and made it faded - so worst case scenario I'll do this, however alum is quite extreme so this approach could make hands look uneven

Regards,

Kaan

[watchweasol]

Hi  There are in the market place ageing chemicals.  Cousins uk have some Im sure its in the catlogue, worth having alook. 

[kaan]

Thank you, it was a good idea, however they don't seem to have anything for gold

[nickelsilver]

Gold doesn't like to tarnish, but it will. How to force it to I don't know, but-

 

A few years ago my workshop neighbor, cabinet maker, asked me to repair some very bent antique brass hinges. I had to anneal them to get them to bend back without risk of breaking, which destroyed the old very dark original patina. To get them back close, I put them in a beaker with a small amount of 25% ammonia in the bottom, and the parts sitting on a block above it. Covered it, and a couple hours later they were pretty much indistinguishable from before annealing. It's counterintuitive, as ammonia is known for brightening brass, but the vapors in a concentrated environment have the reverse effect.

 

Maybe it would work for gold? There is about 12% copper in yellow gold, so, worth a try? If you do, be careful with the ammonia (take usual precautions for chemical handling, 25% is strong stuff)! This is something you definitely want to do outside, or half your house will smell like cat pee for hours, haha.

[jdm]

1 hour ago, nickelsilver said:

Gold doesn't like to tarnish, but it will. How to force it to I don't know

Maybe there is a recipe in this old book. It's straight from alchemist's times.

 

Secrets of the trade. For watchmakers and jewelers (1892).pdf

[StuartBaker104]

How about rose gold plating? You can buy pen plating kits on line - I have successfully used one of these to restore rose gold hands

[kaan]

18 hours ago, jdm said:

Maybe there is a recipe in this old book. It's straight from alchemist's times.

 

Secrets of the trade. For watchmakers and jewelers (1892).pdf 3.42 MB · 3 downloads

Incredible resource, thanks for sharing, I guess if I could find something to bind to silver and remove it from the surface it could've worked too

 

20 hours ago, nickelsilver said:

Gold doesn't like to tarnish, but it will. How to force it to I don't know, but-

 

A few years ago my workshop neighbor, cabinet maker, asked me to repair some very bent antique brass hinges. I had to anneal them to get them to bend back without risk of breaking, which destroyed the old very dark original patina. To get them back close, I put them in a beaker with a small amount of 25% ammonia in the bottom, and the parts sitting on a block above it. Covered it, and a couple hours later they were pretty much indistinguishable from before annealing. It's counterintuitive, as ammonia is known for brightening brass, but the vapors in a concentrated environment have the reverse effect.

 

Maybe it would work for gold? There is about 12% copper in yellow gold, so, worth a try? If you do, be careful with the ammonia (take usual precautions for chemical handling, 25% is strong stuff)! This is something you definitely want to do outside, or half your house will smell like cat pee for hours, haha.

Thanks, luckily I have some 25% ammonia, and it's a very good idea to just let the fumes do their job, I'll try to set something up and test it on a buckle, ammonia is indeed quite dangerous, so I'm trying to think of a convenient way to achieve it - I was always considering dipping, never even considered fuming before

[kaan]

3 hours ago, StuartBaker104 said:

How about rose gold plating? You can buy pen plating kits on line - I have successfully used one of these to restore rose gold hands

They are quite expensive and not available in Turkey sadly, I've asked a skilled watch restorer about it and they weren't doing plating either

Otherwise having steel hands plated could be practical, for the seconds hand, I'm unsure whether the plating could affect the 0.18mm hole though