Don Klipstein wrote:
In article . com, Doc wrote:
When soldering copper pipe, what does the flux do to cause the solder
to get drawn into the joint? Something to do with capillary action?

The main thing I see is preventing oxidation of the metal, ...

True, but the wetting action is also important in helping w/ solder
flow...similar to detergent w/ water on dry glass--it tends to "clump"
rather than flow alone, but a drop of detergent "breaks" the surface
tension. That same action is what helps to ensure full coverage and
the takeup in the joint.

--