What are soldering iron tips like?

Back when I was paying attention to these details:

There were two kinds of soldering iron tips: solid copper, and copper with an iron cladding. The solid copper tips had very good heat conductivity, but would wear away. You had to re-shape them periodically with a hand file (no big deal; copper is quite soft).

An iron-clad tip won't show this wear; you don't have to re-shape them. In fact, attempting to do so would cut through the cladding, and ruin the tip.

Buy yourself a proper small iron for these projects. They're cheap enough, and you'll use it again.

You want to modify soldering tips meant for specific jobs?

That's like turning a dump truck into a race car!

Why not just buy the solder iron and tips needed?

If you are doing a tiny delicate soldering operation then the thing you are doing this too cannot take as much heat as the big tip was designed for. You will damage the item instead if fixing it.

I have built and repaired many items with soldering irons. Best to use the irons designed for the job at hand so no damage or injuries happen.

All of the ones I'm, familiar with are made of copper. Copper conducts heat the best at the lowest cost. You might be able to find a cheap 15-25 watt soldering pencil at Radio Shack for about the same price as making your own. You might even use a 14-16 ga solid copper wire if the soldering pencil uses a set screw to hold the tip in place vs a tip that is threaded.

the tips are copper

It does not matter how big the head is or the wattage the solder has to melt to run