More precisely, flux seals out oxygen which would otherwise react with
the brass and form a non-solderable layer of oxide. With a very clean
joint (both surfaces), flux, good solder, and adequate heat (use MAPP
gas), heat the joint where you want the solder to run. Then apply the
solder and wipe off the excess with a damp rag.


Joseph Meehan wrote:
wrote:
Hi,

I start trying to solder brass valve for one of my garden hoses. The
problem is that the solder does not drawn into the joint. I follow the
instruction on Black & Decker home repair book. Solder melt at the
edge of the joint, then drop on the ground, and it does not suck into
the joint. I tried a couple of times, no solder ever drawn into the
joint and solder stays at the edge of joint, that is it. How am I
going to solder it correctly for brass valve? I heated the center of
the valve back and forth, nothing happened.

thx

To me it sounds like it is not clean enough (flux aids in the cleaning)
or it is not hot enough, in that order.