Zinc & soldering

Good soldering tutorial John, A question though: Is it not
possible to use a flame (torch) to perform this soldering?  One
could obviously not use that flame to provide pressure to the
subject, but perhaps a steel soldering tool? Tom 

G’day Tom et al; Thank you for your kind note. It has been found
easiest to do the preliminary ‘tinning’ with the use of a copper
bitted soldering iron, and this gives excellent control over the
placement of the solder; a narrow strip of solder (tinning) of 3 to
5 mm width along both edges to be joined is all that is necessary.
The final melting of these two strips together can be performed with
a small torch flame whilst pressing down with an iron rod or similar,
immediately after the flame. It is easy for inexperienced persons to
apply too much heat, so the joint melts after it is supposed to have
joined. For large work, a torch is necessary. This method of
soldering is called ’ sweat soldering’ and may be done with ordinary
solder provided both surfaces are properly tinned first. Perhaps I
should mention that tinning solder is available in paste form
premixed with a good flux. DIY shops should stock it. In use, the
work to be tinned is thoroughly cleaned with abrasive paper and the
solder paste painted fairly thinly on the metal, Upon being gently
heated, - best with a torch - the paste melts and excess flux can be
wiped off gently with a piece of rag. This means that tinning can
be done exactly where required. A little extra solder may be applied
when the joint is made. I should also mention that copper and
brass can also be soldered in the same manner. If it is found that in
some places the solder doesn’t run easily then the fault is
invariably that the job wasn’t cleaned properly before soldering
began. Like anything else, the more often the job is done, the
better and faster the result. As I said before, 5 minutes cleaning to
one minute’s soldering.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ