Just out of curiosity, I've just put two Great British designed and built pick ups into my USA-designed, Japanese made Jackson DKM2 guitar in place of the old uns. Very basic soldering job, new soldering iron and I've managed one of the total four connections and seems good. Went to heat connections and ground the earth and no heat from the tip. Soldering iron tip is guffed even though it is new. Can melt the solder (lead-free with flux core) no problem on the SIDE of the iron but the very tip is pretty much useless. Very new to soldering, done it once before with no problems using an electrician friend's kit and not the 30w Â£5 one I bought the other day. Sponged the tip slightly between attempts and kept tinned as best as I could. Any ideas?