It is important that the job is heated evenly to ensure that the metals will be at the right temperature for the solder to flow easily. If thicker and thinner parts are to be joined, heat the thicker parts first, even to the extent of heating only the thicker parts from the back until they are at temperature, then heating only briefly the thinner bits - they will be hot already from being (indirectly) in the flame. A bead of silver solder, held in place by the flux, will melt through the joint when the thicker base is at the correct soldering temperature.
Small amounts of silver solder can be placed along the joint. It is put into place BEFORE heating and lies there held by the surface tension of the flux until it melts. Note that silver solder always flows towards the heat source.
If the assembly is likely to move during the soldering process, wire the parts together with iron binding wire to hold them in place. Useful also when a second soldering operation is necessary on the same assembly. Just remove and discard after soldering. If the part is more complicated, then some thought needs to be given to the sequence of build.
The flux must melt and be active by the time the silver solder melts. Fluxes like most things have a finite life and can become exhausted, depending on how hot and for how long they are heated. Apply flux with small brush when the work has cold.
After the part cools down it then goes into a pickle bath until clean. Once clean, wash the part off in running water.
Don't get the assembly too hot - brass fittings tend to melt instantly if too hot! This is one reason to indirectly heat tthe whole piece. The solder only melts when everything is at the right temperature (rather than melting first in the flame), and goes into the joint. Remember, even heating is better than concentrated heat. As a guide to temperature, the state of the flux or the colour of the metal may be used. The colour of the metal also provides a guide to its temperature, and a little practice on scrap pieces is advisable for beginners.
When heating, it is better to continually move the flame about over the job than to just keep it fixed in one place. And concentrate on heating the whole job, not just one part.
Quenching from the hot state is unnecessary and can be dangerous as steam generates in hollow parts of the work and can be ejected at high velocity, if acid is being used things are worse as fumes are often given off as well. Quenching also produces thermal shock causing uneven stresses and may ultimately damage to the work. Better to let the part cool naturally to room temperature.
After pickling rinse copiously with clean cold running water.
