It would take a huge soldering iron to heat flywheel bolts enough to break the bond on threadlocker. A torch is a necessary evil, but if the flame is adjusted properly the heat can be concentrated pretty accurately on the bolt head. The rifle scope screws I deal with are either #6 or #8, with very little metal mass around them. A flywheel will wick the heat away faster than a soldering iron can produce it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!