Tuesday, September 11, 2007

Making tiny 18 karat white gold tubes

This was a job where I had to make tiny white gold tubes and join them to a fine chain.

It was an antique brooch and the design below was so that the brooch could be worn as a pendant as well.

Basically an engraved whitegold tube through which the pin of the brooch slid and clicked closed.

The two little "loops" behind the chains in the picture were to ensure that the brooch does not fall forward.
I did it as the following pictures illustrate. This is certainly not the only way to do it. One can hand hold and solder as well, but I chose this method because it is accurate consistently.

First, I draw the right diameter wire .

Next, I drill a .5mm hole through the wire. This is done at just about the culet point of the stone to be set

I widen the hole a little bit to accept the jump ring so that it sits nice and flush before it is soldered in

The little jump rings were so small that I modified a double round set of pliers so that they could bend really small diameters.

Like this

These are the un-soldered jump rings. They not really jump rings, but you get the drift...

I put the white gold wire into my soldering tweezers. It just so happened to fit.

That's one side soldered. Careful flame control.

The next picture shows a bad solder joint. I rejected that one because if you solder correctly you have nothing to finish off.

Now I drill the center with a .7 and the a 1mm drill. The the right size ball frazer, so most of the metal is removed . This makes the final shaping much easier when you ready to set. I also drill before I cut them off--much easier to hold

Sawing through the wire, being careful not to saw higher than the hole I drilled, because most of these tubes had closed backs.

When I say closed back, these ones above are open. All the others were closed, because when you have them open, and they turn around on the chain, then you see into the back. This is very noticeable, so it is better to keep the back closed and then bright engrave it.

I took two pieces of nylon and drilled a appropriate size hole so that the clamp holds the tube without distorting it. And of course so it does not slip out when the tube it is being pushed over
when setting the diamond.

This is the rough unfinished setting

The back part being bright engraved.
The rest of the work was simply cutting the chain to the right lengths, joining them with the jump rings shown 3 pictures above and then soldering them closed.
In soldering I used a little torch with a No3 sapphire nozzle. That's a tiny flame and a bit of a mission to keep alive with Oxy-gas, but there is more accurate soldering and less chance of melting everything.

The finished piece . The brooch is a fine example of circa 1920/30 workmanship.
If you have any questions or comments email me on hans(at) meevis.com

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