Soldering gold with swiss torch

First of all, I would like to say hello to everyone. My name is Jae,
and I’m a fresh-out-of-high-school aspiring jeweler-to-be. Pleased to
meet you, and I hope I’m welcome at Orchid. So here’s the question:

I have a Swiss Torch that runs on propane and oxygen. I need to
attach(solder) a channel setting of 12CZs (stones already set on 10k
gold) to a 10k gold model of a human knuckle. The channel setting is
approximately 32mm,4mm,3mm(lwh). The problem I’m having is (from
what I’ve practiced) is that I can’t get all the surface of the
channel setting to flatten out against the model. also, I get fire
scale all over the model. I didn’t have any anti-flux, which
definately was a problem, but I think I was inept at using the torch
properly. Can someone give me a quick rundown on using a Swiss Torch
for this kind of soldering?

Thanks for taking your time to read my question, and I hope to be
able to contribute something as well.

I didn't have any anti-flux, which definately was a problem, but I
think I was inept at using the torch properly. Can someone give me a
quick rundown on using a Swiss Torch for this kind of soldering? 

From your post looks like you having several problems:

  1. Anti-flux. You can buy one in jewelry supply house of your choice,
    or you can use boric acid (my choice) available in any drug store.
    Make sure pieces are clean. Deep it in alcohol (available in Home
    Depot or any paint store) flame the alcohol and dust boric acid over
    the pieces. Use gentle flame to melt boric acid until it forms a thin
    coating.

  2. Swiss Torch. Probably the best there is. Use it as any torch. The
    rule of thumb is never overheat. Use as gentle flame as possible.
    Start with the smallest flame and only increase if required. The size
    and character of the flame depends on size and character of a piece.

Most of the soldering should be done with reducing (slightly
yellowish) flame.

Neutral and oxidizing should be reserved for repairs mostly. Practice
on the scrap to understand effects of the different types… Some book
warn against soldering too slow. While somewhat true for easy
solders, overheating from using too much of the flame is a larger
evil.

  1. Fitting pieces for soldering. The most common mistake that
    beginners make is to use solder as a structural element. Solder
    should only be used to prevent disengagement of mechanical joint. In
    another words pieces must fit and hold together via mechanical
    engagement. There are some exceptions, but it is a good practice to
    follow that rule as closely as possible.

You must ban from your shop tools like “third hand”. They only
promote bad habits. Another advise is never use picks for soldering.
If soldering pick is required, it means that joint was not planned
well. It should always be possible to solder just by placing a small
(as small as possible) square of solder and gently heat until it
runs and locks the joint.

Leonid Surpin