I have to agree with James here. In the course of my work for
different companies I have visited a large number of the UK silver
manufacturing companies and I have not seen one where a 'chlorine’
atmosphere is used for furnace brazing (soldering). Indeed, given
that most brazing alloys (solders) used with silver alloys contain
some zinc this system would not give you a sound joint.
The use of high hydrogen atmospheres, sourced from cracked ammonia,
where the hydrogen content acts as the ‘flux’ for the joining process
are common for furnace brazing (soldering) and I wonder if this is
where a misunderstanding has occurred?