Monday, December 24, 2007

Plating Silver with Paladium, Rhodium

One of the biggest problems in working with silver is tarnishing. You have this lovely piece of silver that you made and after three months in the display window it looks like a dogs-breath. So you polish it, and put it back. Three months later the piece is tarnished again. After a few of these cycles, and if the piece does not sell quick, it starts looking worn and old from all the polishing. What once was pristine now looks old and unsellable because all the corners are now rounded and detail has been lost.
In St. Maarten, at the sea, this problem is magnified . Things tarnish very quickly, and it becomes a real mission to keep multi metal pieces in good condition. Heat- blued titanium does not like being polished inadvertently while the silver surround is being polished.

Also, I like working in silver. Gold is too expensive to work in with a "devil may care about the weight" attitude. Silver is not. So I like to work my 'over the top' pieces is silver. Apart from the ever present tarnishing problem.

So when I read in the Rio-Grande catalogue that palladium can be electro plated directly over silver, I ordered the solution from them. It costs $92 so it is not too cheap.

I had one of my 'over the top' silver rings that I had just finished and I decided to use this and a control ring, on the right, as the test.

This is a picture in a 'light tent' of the silver and gold ring on the left that has been plated with palladium. On the right is the 'control' ring, freshly polished, made of silver and gold. The palladium has a dark, hard, chrome look. It is not to bad if you put it in the window, but it does have a non-silver look. Not warm at all. I was not happy with this experiment at all.
So then, on the instructions on the rhodium bottle, it says that rhodium can be plated directly over platinum. You can't plate it smack over silver, because of the base metals in stirling, I am told.
Well, I figured that since palladium is one of the platinum group of metals, it probably would be OK to plate rhodium over the palladium. I mean, it would not screw up my rhodium solution, since base metals like copper and zinc do that. And be live me, you can screw up your rhodium solution mighty fast if you not careful.

Okay so it is not the silver colour, but it is better than the palladium. It has the chrome look that rhodium always has, but not as much grey as palladium. Anyway, this is a partial solution to tarnishing silver. Not the best, but in multi-metal pieces that I like making, I am going to go this way.
Obviously, in a years time I will be able to give a better road report.
While plating, I masked the gold with black spray enamel paint and a fine brush.I take it off with a solution of paint thinners and acetone.