Here I explain my method of dopping / transfer when a gemstone is cut, using adhesive glue.
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 preferences.
This is the method that works for me. I can't remember when last a stone popped off my dop.
I use a 5 minute epoxy to dop the stone onto the first dop. In South Africa, the glue of choice is Pratley White, but Devcon or Uhu 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 suppliers syringes are notrecommended. As you see, Pratley is different colors, so seeing that it is mixed well, is easy.
This free tutorial follows the same format as all my other free and premium tutorials. This gives you a good insight into the technical teaching methodology.
The syringe lets you dispense small amounts of glue and because it is accurate, the glue bonds very strongly.
I am dopping two peridots, but not all the following pictures will have them. For this gemstone transfer tutorial I used pictures of various stones.
After the pavilion is finished I transfer.
So now I align the stones up properly. Unlike wax or cyanoacrylate, I have plenty of time.
Now comes the trick. After the epoxy has hardened, I use an oxygen/lpg torch, called the little torch. I heat the dop to be removed 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 separates, because 5 minute epoxies fail at about 100C.
I hold the stone in parallel jaw pliers if it is a square stone or a specially bent pair if it is round, tri etc. I am giving GENTLE pressure 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. A set of pliers with nylon lined jaws are the best to use. However, if the stone is very fragile, like some Smithsonite I cut the other day, I hold the dops by hand.Works just as well...
One doesn't have to use a oxy/gas torch. One of those cigar gas lighters work just as well.
Here they are separated. I know this is an Afghan tourmaline. The peridots in the first pictures are long time finished :)
Here are the modified pliers I use for round stones.
And this is how I remove the stone after I have finished the crown 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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