Wednesday, September 26, 2007

Dopping, or Transfering Stones my way.

Firstly, this is the way I do it. There are MANY other ways of doing it and amongst gemcutters, saying one method is better than the other is like arguing about religion or politics.
But I'll say this: so far in ten months I have cut about 170 stones and not lost one off the dop. In fact, the last time I had a stone pop off was in the late 1980's... Go figure..
I use a 5 minute epoxy to dop the stone onto the first dop. Since I come fron South Africa, the glue of choice is Prately White, but Devcon works just as well.

So there are my two dops and a post-it pad to mix the glue on and a toothpick (cheap and easy) and two syringes filled with glue. This I do so that I can dispense the glue easily and accurately.
The syringes that the (Devcon) glues come in are crap. As you see Prately is different colours,
so seeing that it is mixed well is easy.

Like this.

I am dopping two peridots, but not all the following pictures will have them. I culled this tutorial from pictures of various stones.

After the pavillion is finished I transfer.
So now I aline the stones up properly. Unlike wax or cyanoacrylate, I have plenty of time

Now comes the trick. After the epoxy has hardned,

I use an oxygen/lpg torch, called the little torch. I heat the dop at the base with a hot flame. The heat races up the dop and hits the glue. Before it can cross the glue and into the stone, it seperates, because 5 minute epoxies fail at about 100C.
Now I am holding the stone in a parallel jaw pliers if it is a square stone or a specially bent pair if it is round, tri etc. I am giving GENTLE presure on the soldering pad, so that as soon the heat hits the glue the dop gives way.
I hold the stone firmly, not to hard so as to chip it. I also had a set of pliers that had nylon lined jaws but some mother stole them.They are the best to use.
One doesn't have to use a oxy/gas torch. One of those cigar gas lighters work just as well.

Here they are seperated. I know this is an Afgan tourmaline. The peridots in the first pictures are long time finished.

Here are the pliers I use for round stones.

And this is how I remove the stone if it is not too sensitive. Otherwise I turf it into some Attack, an epoxy solvent, or acetone for a day or so.
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