The copper will have a layer of iron plating. The iron plating permits the solder to wet to the soldering iron tip.
It is the ability of tin to dissolve other metals that also reduces soldering iron tip life by dissolving the iron plating and then dissolving the copper until the tip fails.
She featured a lattice of bulkheads, frames and stringers (hull braces) - clad with iron plating
and built with a double bottom.
The first is tin, which is a more reactive metal than iron and will naturally tend to attack the hand tool tips iron plating. The other is Pb-free fluxes, which are more aggressive than those used with ordinary SnPb alloys.
Second, there is a tendency toward more aggressive and frequent cleaning of the tip, which also promotes erosion of the iron plating and leads to more frequent replacement.
Cameron Compression Systems, a leader in the design and manufacture of large reciprocating and centrifugal compression equipment, announced that it now offers electrolytic hard iron plating
(trade name CL2000[TM]) for the protection and restoration of large-bore integral engine power cylinders.
Norfolk contained a large amount of ordnance and was also fairly close to the Tredegar Iron Works in Richmond (a firm with a history of building naval guns and that would now produce iron plating).
 At the outset of the war, Mallory sent a naval officer to Tennessee and Georgia to see whether any rolling mills could roll iron plating; the officer reported that outside of Kentucky, none of the existing southern mills were capable of rolling the two-inch plates needed to armor warships.
The production of iron plating was hampered by a shortage of iron ore, the need to adapt rolling mills for rolling two-inch plate, and competition for the iron from railroads and other military needs.
Pb-free alloys erode the iron plating on solder tips much faster due to the aggressive nature of tin at high temperatures.
To increase tip life, solder tip manufacturers typically increase the iron plating thickness on Pb-free solder tips.
Yet increased iron plating thickness reduces the thermal performance and heat recovery of the tip.