Artificial Toning

[DaveG38]

Apologies if I have raised this question before - the old grey cells ain't waht they used to be. Does anybody know how to artificially tone dipped silver, so that it quickly tones back down to a dull grey? And for the avoidance of doubt, I'm not talking about rainbow toning using an oven. I'm asking because I'm reconstituting a maundy set and the 4d is blast white, whilst the rest are nicely and evenly toned. Yes, I know, why not just buy another better toned 4d and sell the dipped one. I might, but in the meantime does anyone have any recommendations?

[Rob]

Buy a complete set and sell the unmatching ones. Trying to match a set is well nigh impossible. Tried several times and always resorted to square one.

[ozjohn]

Degrease coin with acetone or similar and leave in an oak  cabinet for 6 months to a year and examine after that time. Repeat if not toned  until coin re-tones.

I have heard others say leave out in the weather until coin re-tones.

[Taikonaut]

Leave the coin by the window for a year or two. The extreme temperature changes tend to tone coins quicker.

[DaveG38]

I've now tried a new technique for me, based around my knowledge of chemistry, which seems to have worked. I mixed a small quantity of flowers of sulphur with water and a squirt of washing up liquid (Fairy Liquid for the purists), and mixed it up for an hour or so. Then I placed the silver coin to be toned in the sludge of sulphur at the bottom of the cup. Left it for about half an hour, then turned the coin so that the other side was facing down into the sludge. Then I monitored the toning as it proceeds, regularly turning, until I got the shade of grey that matched the other coins in the made up set. Washed the coin under clean water and dabbed it dry. The result was pretty good, with the fourpence toning slowly and nicely down to very near the other coins over a period of 5 hours or so. No funny colours or other effects, so now the set looks like it has always been together. 

For a control, I also placed a scrap George IV crown into the mix and just left it. The whole thing turned a very dark grey, almost black over 24 hours. I wouldn't recommend this approach, but the method I used certainly brought very good results for a one off coin. The only caveat on this method is that it is important to monitor the coin and turn it regularly, otherwise the toning won't be even from one side to another. I also wouldn't use this technique on anything really valuable, but for a cheap fairly common coin I was pleased with the results.

All this method has done is reproduce, in a cup, the effects of sulphur in the atmosphere over a period of many years. The chemistry is very basic. The sulphur reacts with the Silver and Copper in the surface of the coin to produce the respective Sulphides, which are black. Hence the black tarnish to Silver that accumulates over the years. Simples!

[craigy]

2 hours ago, DaveG38 said:

I've now tried a new technique for me, based around my knowledge of chemistry, which seems to have worked. I mixed a small quantity of flowers of sulphur with water and a squirt of washing up liquid (Fairy Liquid for the purists), and mixed it up for an hour or so. Then I placed the silver coin to be toned in the sludge of sulphur at the bottom of the cup. Left it for about half an hour, then turned the coin so that the other side was facing down into the sludge. Then I monitored the toning as it proceeds, regularly turning, until I got the shade of grey that matched the other coins in the made up set. Washed the coin under clean water and dabbed it dry. The result was pretty good, with the fourpence toning slowly and nicely down to very near the other coins over a period of 5 hours or so. No funny colours or other effects, so now the set looks like it has always been together. 

For a control, I also placed a scrap George IV crown into the mix and just left it. The whole thing turned a very dark grey, almost black over 24 hours. I wouldn't recommend this approach, but the method I used certainly brought very good results for a one off coin. The only caveat on this method is that it is important to monitor the coin and turn it regularly, otherwise the toning won't be even from one side to another. I also wouldn't use this technique on anything really valuable, but for a cheap fairly common coin I was pleased with the results.

All this method has done is reproduce, in a cup, the effects of sulphur in the atmosphere over a period of many years. The chemistry is very basic. The sulphur reacts with the Silver and Copper in the surface of the coin to produce the respective Sulphides, which are black. Hence the black tarnish to Silver that accumulates over the years. Simples!

any before and after pics 

[declanwmagee]

What's flowers of sulphur, Dave?  Chemically speaking, I mean

[DaveG38]

39 minutes ago, declanwmagee said:

What's flowers of sulphur, Dave?  Chemically speaking, I mean

Hi Declan,

Its just powdered sulphur. In the form of flowers its a yellow powder, but if melted, Sulphur turns into a dark red liquid that then solidifies into a similar solid lump. Put a match to Sulphur and it burns with a blue flame and gives off the acrid smelling Sulphur Dioxide.

 

[declanwmagee]

Ah, thanks Dave, so it's the way it's processed.  I thought it might have been an allotrope I hadn't heard of