Hi, Non-temperature soldering iron should be around 25W one.. I'd say. That will keep the soldering temperature ok. Try heating the pin AND the PCB pad together for few seconds and then apply solder to the joint. Once you have enough solder in the joint (less is more here - you can add more, if needed) - remove the solder and heat the joint for another 0,5sec ->1,5sec, remove the soldering iron tip and hope to see a beautiful shining solderjoint to form. Bye, Moebius