Dear all. I want to open a small enameling workshop and I need some information's. Mainly, I want to produce or to restore, enameled badges, orders and other items made from silver or common metals. I wish to know what tools are often used for these jobs? 

I am thinking that I would need a kiln, an electroplating bath, maybe a grinder for polishing metals, a saw... and many other stuff.

I would be more than grateful if you can help me with some information's in this matter.

Thank you,

Best regards.

Alexandru

 

 

 

 

Hi!

First of all, I want to thank you for your reply. I know only what I read here, on the forums. I started doing some restoration with different substances used for modelling, close to resins. It came out good so far. I know that some metals cant be enameled, and for that, I will use copper, brass, silver, or plated copper/brass. In general, medals are made from these metals, some of them silver/gold plated and some only artificially oxidized. As you mentioned, I could use a good book on this direction. I would much appreciate if you can indicate me some titles. In Romania is hard to find these kind of books. 

Regarding the enameling an already electroplated pieces... i found some medals which had gold over a silver base, under cracked enamel. I was wondering if this is possible, knowing that at high temp., the plating is going off the metals because of the heat.

 

Thank you,

Best regards,

Alex. 

For electroplated pieces you have to consider a few things.

First, gold-plated copper/brass has almost always an extra layer, called diffusion barrier, to prevent copper from migrating into gold. This was usually nickel, but since it can cause allergies modern jewelry should come with a white bronze layer instead. Of course this wasn't debated yet when your medals were made, but since you'll have to re-plate you may think about it. For silver on copper/brass or gold on silver, a diffusion barrier is not absolutely necessary, but sometimes a nickel layer was used as it is dense (therefore preventing air to reach the base), cheap comparatively to an equivalent layer of noble metal, and it makes a very shiny surface. It is not necessarily used though. You can test for nickel with dimethylglyoxime (some nickel must be exposed though, it won't work through an intact layer of gold or silver). If there's none, firing at enameling temperatures will definitely alter the plating. In the case of silver-plated copper/brass, silver and copper will form a eutectic alloy that melts at 780°C. In the case of gold-plated silver, silver will migrate into gold and make it turn greenish. The plating won't go off, it's still there but in a form that you don't want. The best you can do is remove the plating first. The cleanest way is by chemical means. For gold, you can use aqua regia (HCl/HNO3 mixture, you'll need a license for HNO3 as it is in the list of explosive precursors in european union) or potassium iodide/iodine mixture. For silver you can use diluted HNO3 or ferric nitrate. For nickel, you can use ferric chloride. You'll need separate tanks for each and waste disposal tanks. Do that in a well ventilated area or under a fume hood, and see how to dispose of the wastes according to regulations in Romania.

Second, be careful with solder. It's likely that it won't stand firing temperatures. If there's any, you should remove it.

Third, when you re-plate, you should use a tanks and electrodes adapted to the shape of your piece. If your medals are reasonably flat, you should use a rectangular tank with a wide electrode facing the side you want to re-plate. If the electrode is too small or misplaced, you'll plate your piece irregularly. The side which is not facing the electrode will plate very slowly, if at all. Therefore you'll have to turn your piece as well.

Fourth, you need a good constant current supply. The plating speed depends on the current, which needs to be either stable or pulsed in a well-defined way.

Fifth, plating will only happen on conductive surfaces. They must therefore be free of oxides.

I'd be you I'd test on scrap pieces first before feeling confident enough to try my luck on a valuable item.

Also, since you aim at restoring antiques, you may have to do a bit of research in the composition of the enamels made back then. For instance, reds, oranges and yellows nowadays are often based on cadmium. Cadmium pigments appeared in the 19th century. Maybe an enamel producer may tell you when they found their way into enamel, and what was used before that (cinnabar?). Another example is arsenic white, which is nearly not used anymore. Since you'll have to fire your pieces, and unless you scrape off all the enamel first, you'll need to know how these colors evolve when fired, which ones are compatible with what, how they may react with new colors, and so on.

Anyway, that's it for my 2 cents. Good luck!

 

Hello Vincent. Thank you for your input. I will have in mind these valuable information's. Cam I contact you in privat for further discussions? What I missed from the first post is that besides restoration I also wish to produce enameled items as badges, orders, medals, etc. That is the reason why I asked here what tools I would need for this. Any way, I want to thank you all for help.
Best wishes,
Alex

Hi Alexandru. Feel free to ask questions, I'll try to answer them when I've time (and if I know the answer).