In article ,
Lobster wrote:
People keep talking about heating for a few secs; well it's taking me
more like 1-1.5 minutes to get the joint up to enough temperature to
melt the solder. And all that time the flux is boiling/burning off I
think. But heated for less than that time, I push the solder against
the pipe and it *just* melts, forming a blob which immediately
solidifies without running up the fitting,

Are you applying the solder to the same side as the flame? Because the
flame will melt the solder even if the fitting isn't hot enough. So the
solder should be applied somewhere out of the flame.

The flux will melt before the correct temperature is achieved, but by this
time will have done its work.

because the pipework/fitting
isn't hot enough. I'm using an ordinary butane cartridge blowlamp, with
a brass burner approx 15mm diameter and which seems to give out a good
blast of flame, and I'm using the hot part of the flame, not the blue
unburnt area. Does this make any sense?

You don't want the flame too close, so use the blue part. And move it
around to heat all the fitting evenly. A tip is the blue flame will change
to a greenish colour when the copper is up to heat.

IMHO, it's best to use an aggressive flux. Then wipe the pipes clean with
a damp cloth after they have cooled.

--
*Don't worry; it only seems kinky the first time.*

Dave Plowman London SW
To e-mail, change noise into sound.