Here's some old school tech for you guys to munch on. This trick was shown to me by an old timer whom I thought was nuts until I saw it in action. This is especially effective if your working on something where the replacement part isn't easily available.
In the case of a fan blade, heat the hub up with your b-tank (doesn't need to be red, just heat it up a bit), pull the torch back, get your head out of the way because there's gonna be smoke, and jam a dinner candle right into the space where the hub meets the shaft. (Not the whole thing, maybe a half inch worth off the candle) The candle doesn't need to be lit, and no I'm not lit either. The wax gets drawn in between the hub and shaft (capillary action) lubricating it and keeping it from seizing again as it cools down. Slap on the Ultimate puller, and yank it off with your impactor.
This works great on rusted nuts also like lug nuts and so forth. I usually try PB blaster and ultimate puller first, and if I can't get anywhere with that, then the candle trick comes out to play.