Quote Originally Posted by JohnnyK View Post
I've never had any luck with the cold sprays on 'really' stuck bolts. Maybe it works fine on stubborn bolts.

Generally you need the bolt red hot. Whether it be from oxy-fuel or induction, that doesn't matter (I have an induction tool, but it's pretty cumbersome). As mentioned, propane takes so long (and won't ever get hot enough as far as I am concerned), you start heating other parts as you wait.
Actually that sort of makes sense. Freezing the bolt changes the temperature perhaps -40*C, while heating it might add several +100*C's, which means the change in volume is gonna be that much bigger. I'll try the acetone/ATF fluid + an induction tool.