I have tried to solder 4-40 rod to GP Threaded Couplers using 60W iron and GP sliver soldering kit but i have failed.
I worked according to rcuniverse article clean,flux,heating up the coupler to a point the solder would melt right into the joint but this has never happened. The solder could reach this melting point even thought i let the coupler to be heated for more then 10m.
After many tries i got a help from a electrical technician which used it's own solder and flux to directly melt the solder (not heating the coupler) this method seems to work .

what i really would like to know is :
1) what i was doing wrong with GP soldering kit ?
2) is the electrical soldering going to hold ?

thanks