Ok, from my previous post I received a number of replies commiserating me for the failure of my titanium experiment.
Failure is to me only another way that points forward.
As in, try another way.
One always learns something from failure , so it is never wasted.
The copper backed method is also not a new way to plique a jour. It is known by it’s Japanese name of shotai-jippo.
Anyway, here is the Wiki link that explains how clueless we actually are today.
So, because I had purposely overheated the piece all the enamel was ruined. It fell out.
So I used the exact titanium piece for another experiment.
I figured that the enamel was not ‘wetting’ the titanium, so I copper plated the test piece.
Metallic copper does not bond well to glass but its oxide, Cu2O, is wetted by molten glass and partially dissolves in it, forming a strong bond.
And the oxide also bonds well to the underlying metal.
The glass-oxide bond is stronger than glass-metal.
And for good measure I made a titanium ring and a large silver test piece as well.
The titanium ring I didn’t copper plate just as a second test to see if titanium really didn’t like enamel.
And the silver washer just to see how big can I make plique a Jour. This one measures 40mm inside diameter.
Packing. I always use distilled water to wet my enamels.
After the second firing, it looks rough, but not really. So, instead of pealing the copper off the back, I rather etched it off.
Because this is purely experimental I didn't bother to check is the etching solution would actually attack the enamels.
In this case the pink went south.
I have some painful experience with this.
Many, many years ago, in the early 1980’s I was about two years into the jewellery trade and I made this 18ct plique a ' jour butterfly. I had never enameled anything before and taking small steps was not in my vocabulary.
Which just goes to show that the lord protects the ignorant....
Curved and domed, 18ct, with a mix of colours that only the young can envisage, it nevertheless took me 120 hours of work to finish. I didn’t use copper as a backing, but a foil of aluminum bronze, which does not allow the enamel to stick to it.
Problem was there was no internet so all I had was some books on enameling in general, and in there they said that to remove the metal oxidization, “ just pop it into sulphuric acid” and no harm will come to enamel.
Ha, the acid ruined the enamel so badly I had to break out half of it and start again.
But once something like that happens, it never comes right and I have had it in my safe for thirty years.
To ugly to sell and to pretty to destroy.
Anyway, just as an aside, I use the Edinburg etching solution this time
4 parts ferric chloride plus 1 part citric acid solution give you the Edinburgh etch.
Here is more. http://www.lawrence.co.uk/acatalog/etch.pdf
Another ruined test.
At 40mm diameter, I seem to have reached the limit with torch firing.
I know it is too big. But this is just experimenting to push the limits. I’m sure if I annealed it in my vacuum oven for a couple of hours, I would be ok. Those experiments I am busy with as we speak.
This was the titanium ring. The expansion co efficients are radically different between titanium and glass.
Here is a chart for all the eco’s
I expect different titanium alloys and different suppliers of enamel might give success , but I am only testing. I don’t have at this time any intent to make something plique-a-jour with titanium.
Do not think I am scared to do things a million times over until I get them right. OK, maybe not a million, just twenty or so…
So I plated the titanium ring and then put the old enamel back, added some more around the outer border and fired it again.
Didn’t work. The whole thing popped out.
I also made a silver control, same size as the titanium washer.
Just to make sure .
This allowed me to take a photograph, showing for the first time in the history of enameling, precisely how all the little elves and gnomes that live in all the Faberge eggs around the world see the outside world.
So next time you are in some fancy Russian or Italian museum specking the plique-a-jour out, just remember, there is a little person behind that glass, specking you right back.