Freeing Rusty Fasteners With a Blow Torch

#7 place wet rags on the metal tubing, block, and hose to sink the heat and avoid damaging those parts. Heat only the nut.

In reply to FMB42 :

Not sure what it's worth, but I learned the torch method of removing rusty fasteners in a fairly large autobody shop in the late 60s.

Of course, we used oxy acetylene for many other tasks as well....an important tool in the body shop. [Yes, I'm aware of spot and MIG for panel repair now.]

Torch also handy for bending /straightening/ shrinking/ heat-treating/ annealing in the metal fabrication shop.

I'd suggest that when you buy torque wrenches, micrometers, Calipers...you're ready for a torch as well.   It's a higher skill, and requires higher effort to learn and master.

In reply to FMB42 :

Not sure what it's worth, but I learned the torch method of removing rusty fasteners in a fairly large autobody shop in the late 60s.

Of course, we used oxy acetylene for many other tasks as well....an important tool in the body shop. [Yes, I'm aware of spot and MIG for panel repair now.]

Torch also handy for bending /straightening/ shrinking/ heat-treating/ annealing in the metal fabrication shop.

I'd suggest that when you buy torque wrenches, micrometers, Calipers...you're ready for a torch as well.   It's a higher skill, and requires higher effort to learn and master.

In reply to FMB42 :

FWIW, I haven't lived in the rust belt since 1976 [Hallelujah], but I use the torch on every exhaust system fastener, and optionally on any unhealthy-appearing one, BEFORE it breaks.   When you have a tool, use it.  When you don't, tell yourself why you don't need it...often.

There's a chem called SILKCROIL that works GREAT! I USED IT ON AN EXHUAST on a 48 Chrysler and it all came apart easily something that NEVER happens

There's a chem called SILKCROIL that works GREAT! I USED IT ON AN EXHUAST on a 48 Chrysler and it all came apart easily something that NEVER happens

Don't believe me.   But I've never broken a bolt on a Jaguar.   Honest, sometimes a really rusty one will politely ask me to use a spray lubricant and let it sit for a day  or two  but then will just spin right out.  
        But it's never been rude enough to demand such treatment. Nor have I ever offended Jaguar nuts and bolts with a torch.  
 Can't say anything like that about all the Chevy's etc.  I've worked on.  

I'm not gonna lie I have a torch and rarely use it. Generally I just get a bigger impact. Tighten then loosen.

I've had a few awful nuts in my time where I've struck an arc on the dam thing with my tig torch to try and get it hotter than map gas torch could. One trick for the best penetrating oil is acetone and ATF shaken up. 
 

Embrassingly I spent 2 full days on a strut bolt recently, heat and oiled that sucker for hours and began working it back and forth with the 700ft lb impact, just turning the slightest amount each time, being gentle and after an hour of this it finally snapped. At that point it took me about 2 minutes to drill it out and put a new bolt in, and curse myself for wasting a day.

I have a HomeDepot MAPP and O2 kit in the garage and while it's not very useful for welding (brazing, yes) it works like a charm on heating stuck bolts. It's also not very expensive and quite portable.