On 2/6/2012 3:22 PM, teabird wrote:
Hello,

I have some 1/2 inch type M copper pipe and 4 90* elbows that I'm
sweating together for practice. I've cut some 8 inch pieces and
yesterday was able to solder one end of each ell to 2 tubes. It took
a few extra tries but I was able to draw the solder into the joint
pretty well. There was alot of smoke created, white and brown. I'm
using yellow canister (Map gas?), cleaning the joints with emery
cloth, flux and using lead free solder.

Today I can't seem to get the solder to draw in. I've prepared the
joints as before and am attempting to create a square with the tubes
so this time the ell is connected to 2x 8 inch pieces. I also notice
that even though the solder is eventually melting it is not drawing in
the joint, and when it hardens it has a yellow color to it.

Is the yellow color significant and does it indicate a problem with my
technique? Can there be a noticable difference between yesterday and
today as relates to how quickly the joint heats up, as today I have 2x
the amount of tube to heat?


In addition to the other good advice
You may be melting the solder with the torch. The pipe needs to be hot
enough to melt the solder [torch can help].

It is also possible to heat the joint too hot and screw up the flux.
(Not likely what is happening.)