On Wednesday, February 10, 2016 at 8:38:54 AM UTC-5, Julian Barnes wrote:
On Wed, 10 Feb 2016 04:41:37 -0800, John-Del wrote:

Not sure either, but I often use hot air to preheat the area before
using the iron. Nothing ruins desoldering faster than heat sinking.

And nothing ruins germanium semis faster than NOT heat sinking.

Not sure of your point, but what I'm referring to is the heat sink action of a multi layer PC with a huge ground plane running on or in it. Placing a soldering tip on some points can actually freeze the tip to the joint in worse cases, or prevent complete solder melting inside a plated through hole.. Anybody who has replaced an IPM on an LG sustain board can attest to this. Preheating the board minimizes excessive loss of desoldering tip heat to surrounding areas.