Remember to add some flux.

I was using rosin & yes I have a tin of flux somewhere. I was surprised at the probs I was having as usually that foot long heavy duty iron handles any job though it takes forever to heat up 2 get started

It's possible your tip is contaminated, sand it all the way down and re tin.

I have never used flux when soldering wires, not saying it's wrong.
This one has a hi and low depending on how far you pull the trigger. Radio shack special,150/230 watts, the solder comes in different diameters and say rosin core solder on the roll.

Now I think it's different than the solder I have to solder copper pipes?

I worked for 8 years at a scale company. One of my jobs was to replace 16 pin IC chips in digital display boards. Sometimes there was like 12 chips per board X 16 pins. That's a lot of soldering with one of these and a solder sucker.

flux is more of a plumbing thing but can't hurt. it helps the solder bind with the metal. and yes, you would use a solid core with plumbing.