In article ,
"Arfa Daily" wrote:

snip
better job of conducting heat from the iron tip down into the PCB hole.

That's probably true, but there's also a lot of amalgamation going on.
That's why copper soldering iron tips get pitted from solder; it
amalgamates with the copper.

What a shame lead-free doesn't do the same ... d;~}

Seriously though, most soldering iron tips have been made from nickel plated
iron rather than copper, for many years now, and they get just as pitted as
the copper ones did, but at least you could file the copper ones down. I
never used to put a new bit in my old Adcola, until it was a 'stump'. I am
more of the opinion that tip erosion, both back then and now, is caused
mainly by the mildly corrosive action of the flux in the solder core, and
that the nasty gob of metal that you find on the tip when the iron hasn't
been used for a while, is oxidised components of the original solder
almalgam. Smitty, what thinks you ?

Arfa

I haven't looked into this so much, so can't comment intelligently on
tip degradation. Actually the symptom that tends to arouse my curiosity
the most is the burr that often forms on the end of the tip. The one
that snags and tears at the sponge as you wipe it. Where the hell does
that come from? Mechanical abuse is my only guess. I'll sometimes put up
with diminishing performance from other issues, but that one so
interferes with ease of use that it warrants immediate replacement.

The worst thing for a tip, I think, is to leave the iron on for extended
idle periods. Use it all day long every day for a month and it's fine.
Leave it on overnight once, and it's shot.

BTW, I agree with you and others on the maintenance necessity regarding
desoldering stations. The difference in performance between a
well-maintained machine and a neglected one is staggering. I'd add to
all the other comments that a fresh tip there works wonders, too. I like
to do a regular shotgun routine frequently on my Hakko:

Empty and completely clean residue barrel, replace steel wool ball,
replace both felt filters. With unit hot, remove and discard tip. Run
the poker through the suction tube (The larger diameter poker does not
fit through the tips, so this must be done without a tip.) Install new
tip with anti-seize compound on the threads. Try not to breathe fumes
from smoldering anti-seize as I install new tip on hot barrel. Paint a
tiny smear of O-ring lube on the residue barrel ID near both ends, where
it mates with O-rings, then reinstall.

I do keep a supply of new tips in the 0.7, 1.0, and 1.3 mm sizes, and
use a size appropriate for the work at hand.

Besides maintenance, also agree that technique is crucial, and a skill
that must be learned by experience.