You can make your soldered joints any way you like. But you should
realize
that you're doing newbies a disservice when you advise them to heat the
pipe
and the fitting: that's *not* the best way to make the joints. The
joints are
easier to make, and less likely to leak, when only the fitting is
heated. It's
just plain silly to advise someone who's never soldered copper before
to heat
the pipe first. There is a better and easier way to do it.

--
Doug, the people who make copper fittings and the people who make
soldering alloys do test soldering all the time. They use different
methods to see what is the best way. Then they cut the joints apart to
see which way makes the best joints. They also pressure test ant
stress test the joints till they fail. I have been to a number of
seminars in addition to doing soldering and brazing for the last 35
years. The research shows that it is best to heat the pipe first, then
the fitting. Keep the torch moving all the time. That will make the
strongest, leak free joints. The best way to start is to do it the
best way.

Stretch